SERVICE MANUAL - Aqua-Hot Heating Systems, Inc.

SERVICE MANUAL - Aqua-Hot Heating Systems, Inc.
AHE-600-D03
AHE-675-D03
SERVICE MANUAL
© 2010 Aqua-Hot Heating Systems Inc.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 2 —
Table of Contents
Section 1: Introduction to the Aqua-Hot 600-D03
Introduction ............................................................................................................ Page 6-8
Danger, Warning, Caution, and Note Box Definitions............................................. Page 6
Model Differentiation .............................................................................................. Page 8
Section 2: Aqua-Hot Hydronic Heating System Overview
Technical Information…………………………………………………………………….Page 9
I.D. Label Sample ................................................................................................... Page 10
Component Overview ............................................................................................. Page 11-13
Aqua-Hot Operational Flow-Chart .......................................................................... Page 14
Antifreeze & Water Heating solution...................................................................... ..Page 15-16
Section 3: Interior Switch Panel
Diesel-Burner Switch .............................................................................................. Page 17
Engine Preheat Switch ........................................................................................... Page 17
Electric Element Switch .......................................................................................... Page 17
High/Low Switch (Electric Element)........................................................................ Page 18
Pin Label ................................................................................................................ Page 19
Section 4: Exhaust System Requirements
Exhaust System Requirements ………………………………………………………….Page 20
Section 5: Aqua-Hot 600-Series Components
Interlock Switch ...................................................................................................... Page 21
Fluid Level Sensor ................................................................................................. Page 22-23
Control Thermostat................................................................................................. Page 23-24
A.C. High Limit Thermostat (Right)......................................................................... Page 25
A.C. High Limit Thermostat (Left) ........................................................................... Page 26
D.C. High Limit Thermostat .................................................................................... Page 27-28
Check Valves ......................................................................................................... Page 28-29
Tempering Valve .................................................................................................... Page 30-31
Circulation Pumps 1, 2, & 3 .................................................................................... Page 32-33
Engine Pre-Heat Pump .......................................................................................... Page 34-35
Electric Heating Element (Right) ............................................................................ Page 36-37
Electric Heating Element (Left) ............................................................................... Page 38-40
A.C. Relay (Right) .................................................................................................. Page 41
A.C. Relay (Left) ..................................................................................................... Page 42-43
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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Section 6: Electronic Controller
General Facts ........................................................................................................... Page 44
Secondary 12 Volt DC battery Connection ............................................................... Page 45
Terminal Strips with Screw-Type Fasteners ............................................................. Page 45
Low Voltage Reset Feature ...................................................................................... Page 46
Replacement Procedure ........................................................................................... Page 47
Proper Jumper Pin Formation .................................................................................. Page 47
Section 7: Electronic Controller Indicator Lights
Electric Heating Element Status Indicator Light ..................................................... Page 48
Heating Zones Status Indicator Lights 1-5 ............................................................. Page 48
Low Battery Voltage Fault Indicator Light ............................................................... Page 48
Low Temp Cutoff Status Indicator Light ................................................................. Page 48
Low Tank-Level Cutoff Indicator Light .................................................................... Page 48
Heating Status Indicator Light ................................................................................ Page 48
Engine Preheat Pump Indicator Light ..................................................................... Page 49
[Circulation] Pump #1 Indicator Light...................................................................... Page 49
[Circulation] Pump #2 Indicator Light...................................................................... Page 49
[Circulation] Pump #3 Indicator Light...................................................................... Page 49
Diesel-Burner Status Indicator Light ....................................................................... Page 49-50
Overload Fault Indicator Light ................................................................................ Page 50
Section 8: Diesel-Burner
Overview ................................................................................................................ Page 51
I.D. Plate ................................................................................................................ Page 51
Diesel-Burner Overview ......................................................................................... Page 52
Diesel-Burner Operational Flow Chart .................................................................... Page 53
Diesel-Burner Operational Overview ...................................................................... Page 54-56
Section 9: Detaching and Reattaching the Diesel-Burner
Detaching the Diesel-Burner .................................................................................. Page 57-59
Reattaching the Diese-Burner ................................................................................ Page 60-62
Section 10: Diesel-Burner Components and Repair Information
Diesel-Burner Component Overview
Page 63
Motor ...................................................................................................................... Page 64-67
Flame Sensor ......................................................................................................... Page 68-69
Ignition Electrodes .................................................................................................. Page 70-71
Fuel Nozzle ............................................................................................................ Page 71-72
Fuel Solenoid ......................................................................................................... Page 73
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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Section 10: Diesel-Burner Components and Repair Information (continued)
Fuel Pump .............................................................................................................. Page 74-76
Bearings ................................................................................................................. Page 77-79
Ignition Coil ............................................................................................................ Page 80-81
Controller ................................................................................................................ Page 82-83
Section 11: Troubleshooting
If the Aqua-Hot is Black Smoking
Page 84
If the Aqua-Hot is Blue/White Smoking .................................................................. Page 85
If one of the Aqua-Hot’s Heating Zones will not get hot.......................................... Page 86
If there is a lack of domestic continuous hot water ................................................. Page 86-87
If there is antifreeze leaking ................................................................................... Page 87
Appendix A: Wiring Diagram .........................................................................................Page 88-91
Appendix B: Wire Gauge Chart ......................................................................................Page 92-93
Appendix C: Fuel Pressure check and Adjustment .....................................................Page 94-99
Appendix D: Extreme Cold Weather Operation ........................................................Page 100-101
Appendix E: Aqua-Hot Annual Maintenance ............................................................Page 102-115
Appendix F: Winterization ................................................................................................. Page 116
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 1: INTRODUCTION
This service and parts manual is designed to aid
trained and qualified service technicians with
the process of troubleshooting and servicing the
Aqua-Hot 600 series Hydronic heating system.
The Aqua-Hot 600 heating system features a 12 Volt-DC
powered diesel-burner and two AC powered electric heating
element. These two heating sources are used in conjunction
with an FDA-approved “GRAS” (Generally Recognized as
Safe) propylene glycol based boiler antifreeze and water
heating solution in order to provide a continuous supply of
domestic hot water, interior/fresh water tank heating, independent interior zone heating, and engine preheating. Be
sure to reference Figures 3 through 5 for a complete component overview.
Please note that all Danger, Warning, Caution, and Note boxes, appearing as needed throughout this manual, must be
reviewed and adhered to during any service procedure in
order to avoid potential hazards, which could result in injury,
product damage, or property damage.
Should additional assistance be needed, please contact the
technical support department at 1-800-685-4298, Monday
through Friday, between the hours of 7:00 AM and 4:00 PM
Mountain Standard Time.
TO THE
AQUA-HOT 600 SERIES
Understanding the Aqua-Hot 600’s Major Systems:
The basis for the Aqua-Hot heating system’s functionality is
the antifreeze and water heatng solution, which is comprised
of water that is distilled, de-ionized, or soft, as well as FDAapproved “GRAS” propylene glycol based boiler antifreeze.
Through this solution’s ability to maintain and transfer heat,
the Aqua-Hot’s three major systems: the domestic water
system, engine preheat system, and interior heating system,
are able to function effectively. This antifreeze and water
heating solution is contained within the Aqua-Hot’s boiler
tank and is heated by the diesel-burner when its operating
criteria are met and/or the electric heating element when its
operating criteria are met. In order for the diesel-burner to
be considered as a heating source by the Aqua-Hot, it must
have an adequate fuel supply, receive power from the electronic controller, and be selected as a heating source from the
interior switch panel. In order for the electric heating element to be considered as a heating source by the Aqua-Hot,
it must receive power from either a generator or from shore
power and be selected as a heating source from the interior
switch panel. Once the antifreeze and water heating solution
achieves operating temperature (as determined by the AquaHot’s control thermostat), the domestic water system, the
engine preheat system, and the interior heating system are
permitted to operate as needed.
Domestic Hot Water System:
Danger, Warning, Caution, and Note Boxes:
Danger, Warning, Caution, and Note boxes appear throughout this manual as a means of alerting the service technician
to important information.
INDICATES THAT PERSONAL INJURY IS LIKELY OR
IMMINENT.
Indicates that serious damage to the heater will occur
and personal injury is possible as well.
Indicates that damage to the heater is possible.
NOTE: Indicates information that requires special attention by the service technician
When hot water is requested, domestic water from the motor
home’s fresh water tank is transported through a copper coil
in the Aqua-Hot’s boiler tank where heat is transferred from
the heated antifreeze and water heating solution to the domestic water flowing through the copper coil. The heated
domestic water then flows through the tempering valve to be
mixed with cool water from the fresh water tank to achieve
an appropriate temperature before it flows to the faucet requesting hot water.
Engine Preheat System:
The engine preheat system is responsible for heating the motor home’s engine block in order to make it easier to start-up
when cool weather conditions exist.
When the engine preheat system is activated via the interior
switch panel, the motor home’s engine coolant is circulated
through a dedicated copper coil in the Aqua-Hot’s boiler
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 1: INTRODUCTION
tank, where heat from the antifreeze and water heating solution is transferred to the motor home’s engine coolant. The
heated engine coolant is then transported back to the engine
where it transfers the heat to the engine to gradually warm it.
Additionally, the Aqua-Hot 600 includes a Motoraide feature, which uses the circulation of the motor home’s engine
to transport the engine’s coolant from the Aqua-Hot’s boiler
tank to the motor home’s warm engine and back to the boiler
tank. Through this process, the boiler tank is kept heated,
which reduces the time required to bring the tank to operating temperature for interior heat and continuous domestic hot
water. This Motoraide feature is part of the engine preheating feature and plumbing system, and requires no action on
the user’s behalf to function.
Interior Heating System:
The interior heating system is responsible for providing heat
to the motor home’s interior in order to maintain the temperature at a comfortable level.
For interior heating, it is the room thermostats that trigger the
Aqua-Hot’s interior heating system. When a thermostat recognizes that heat is required in a particular area, it sends a
signal to the Aqua-Hot’s electronic controller calling for
heat. The Aqua-Hot responds by activating the circulation
pump for that zone, which sends the heated antifreeze and
water heating solution through the Heating Loop corresponding to the zone requesting heat. The fans on the heat exchangers in the zone calling for heat are also activated; therefore, as the heated solution flows over the heat exchanger’s
fins, the heat is transferred to those fins and dispersed into
the interior of the motor home by the fans. Until the thermostat signals that heat is no longer required, the Aqua-Hot will
continue to send the heated antifreeze and water solution
through the loop, which returns the cooled solution to the
Aqua-Hot’s boiler tank to be re-heated before being sent
back through the loop again. This process continues until the
pre-set temperature of the interior is reached, and the interior
room thermostat signals the electronic controller that heat is
no longer required.
TO THE
AQUA-HOT 600 SERIES
AC Circuit:
Although the diesel-burner is the primary heating source for
the Aqua-Hot and is necessary for providing continuous domestic hot water, an alternate heat source exists for moderate
temperatures, which functions with an AC circuit. Whenever
the motor home is connected to an AC power source plugged into shore power or using a generator, the AquaHot’s electric heating elements (2) have the ability to function in order to provide heat for the boiler tank.
When the antifreeze and water heating solution falls below
operating temperature (as determined by the control thermostat), a signal is sent to the electronic controller requesting
heat. Because the electric element switch is activated on the
interior switch panel, the DC power from the electronic controller is permitted to flow to the AC relay, which activates
the relay in order to allow AC power to flow to the electric
heating element. When the electric heating element receives
power, it becomes active and supplies heat to the boiler tank
until operating temperature is reached.
NOTE: The Aqua-hot 600D is equipped with 2 - 2000 watt
120 Volt A.C. electric heating elements. The Aqua-Hot
675D is equipped with 1 - 2000 watt 120 Volt A.C. Electric
element along with 1 - 4500 watt 240 Volt A.C. electric
heating element. To operate both electric elements simultaneously, the motor home must be plugged into a 50 amp
circuit. Therefore, when there is less than 50 amp service
provided, there is a Hi/Low switch where only one electric
element can be activated by switching the switch to low.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 1: INTRODUCTION
TO THE
AQUA-HOT 600 SERIES
Aqua-Hot Model Differentiation (600 series)
Aqua-Hot Heating Systems, Inc. Manufactures two individual models of the Aqua-Hot 600 series Hydronic Heating Systems. The
varying factor between these two models is the output of the Electric Heating Elements featured. In order to determine which of the
following Aqua-Hot models has been employed, locate the Marking Plate on the Heating System (reference Figure 2 For Marking
Plate information) and view the Model number.
AHE-600-D03:
This model features two 120Volt A.C./2000 Watt Electric Heating Elements.
NOTE: Reference “Appendix A” for Wiring Diagram
AHE-675-D03:
This model features a single 120 Volt A.C./2000 Watt Electric Heating Element and one 240 Volt A.C./4500 Watt Electric Heating
Element.
NOTE: Reference “Appendix A” for Wiring Diagram
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Figure 1
Diesel Burner, Heat Input (Firing Rate) ..................................................................................................................................... 56,000 BTU/hr
Diesel Burner, Fuel Consumption (Continuous Operation) .......................................................................................................... 0.40 gal/hr
Heater, Voltage/Maximum Power Consumption ........................................................................................................ 12 Volt-DC/60 watts
Electric Heating Element specifications 600 .......................................................................................................(2) 120 Volt-AC/2000 watts
Electric Heating Element specifications 675 .............................................. (1) 120 Volt-AC/2000 watts & (1) 240 Volt-AC/4500 watts
Zone Heat Circulation Pump specifications.................................................................................................... (3) 12 Volt-DC/21 watts each
Number of Heating Zones ...................................................................................................................... Maximum of 5, plus Engine Preheat
Domestic Water Heating Capacity ............................................................................................................................ Continuous/On-Demand
Dimensions ................................................................................................................................................................ 18.5”H x 18.5”W x 36.75”L
Dry Weight .......................................................................................................................................................................... approximately 186 lbs.
Wet Weight .......................................................................................................................................................................... approximately 303 lbs.
NOTE: All vehicle installations must comply with the requirements listed in the Recreational Vehicle Industry Association’s (RVIA) ANSI/NFPA 1192 Handbook for Recreational Vehicle Standards. To receive a copy of this handbook
and other pertinent RVIA Standards, write to: Recreation Vehicle Industry Association, 1896 Preston White Drive,
P.O. Box 2999, Reston, VA 22090-0999, call them at (703) 620-6003, or visit them online at www.rvia.org.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Each Aqua-Hot heating system possesses an I.D. label on the
unit itself. This I.D. label details the specifications of the
heater, to what standard it has been tested, and important
safety notices.
Figure 2
Use a 25
1 inch
3 inches
3 inches
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Figure 3
Thermostat
Access Panel
V.A.C. Wiring
Access Panel
Interlock
Switch
Zone 1
Circulation
Pump
Zone 3
Circulation
Pump
Zone 2
Circulation
Pump
Domestic Water
Access panel
Engine Preheat Pump
Diesel Burner
Diesel Burner
Controller
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
Drain Valve
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Figure 4
AC Wiring
Ports
Air Release
Valve
Zone 1, 2 and 3
Inlet Ports
Expansion Tank
Connection
Wiring Harness Port
Zone 1, 2 and 3
Outlet Ports
Product ID Label
Engine Preheat
Inlet/Outlet
Ports
Domestic Water
Inlet/Outlet
Ports
Diesel Fuel
Inlet/Outlet
Ports
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Figure 5
Control Thermostat
Thermostat Access Panel
Fluid Level Sensor
D.C. High Limit
Thermostats (2)
A.C. High Limit
Thermostat
A.C. Relay
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Heat Source is
selected from the
Interior Switch
Panel
Chart 1
“Diesel Burner”
Switch Turned On
“Electric Element”
Switch Turned On
Diesel-Burner heat
source selected by
Diesel-Burner Switch
Electric Heating Element
heat source selected by
Electric Element Switch
Diesel-Burner fires
into the Combustion
Chamber, which heats
the antifreeze and water heating solution in
the Boiler Tank
Electric Heating Element
activates, which heats the
antifreeze and water heating solution in the Boiler
tank
10-20 minutes
NOTE: The DieselBurner and/or Electric
Heating Element (as
switched ON) will automatically begin reheating the antifreeze and
water heating solution
drops below 160 °F
Boiler Tank heats to
190 °F
1-2 Hours
Zone Thermostat
calls for heat
The Engine Preheat
switch on the Interior
Switch Panel of the Motor Home is activated.
The Circulation
Pump activates for
the Zone which
called for heat. The
heated antifreeze
and water heating
solution is transported throughout
the plumbing lines
the that zone.
Heat is transferred to the
Engine Preheat System
The cooled antifreeze
and water heating solution is returned to the
Boiler Tank to be reheated
Heat Exchanger
fans activate
Heat is transferred into
the Zone calling for
heat
Antifreeze and water heating solution
moves through the
Heat Exchangers in
the Zone calling for
heat
The engine’s coolant is
circulated through the
Aqua-hot’s internal Engine Preheat System,
where the heat from the
Boiler Tank is transferred to the engine’s
coolant.
A hot water faucet (e.g.,
kitchen sink, shower,
etc.) calls for hot water
Heat is transferred to
the Domestic Water
System
Continuous hot water is
supplied to the faucet
The antifreeze and water
heating solution within
the Boiler Tank is reheated, as needed, and
continues warming the
engine’s coolant as it
circulates through the
Aqua-hot’s internal Engine Preheat System
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Antifreeze and Water Heating Solution:
As the antifreeze type and mixture ratio is essential to the
Aqua-Hot’s performance and ability to comply with regulations, the following information is being supplied to
understand various types of antifreeze, the quality of water necessary, and the mixture ratio. Aqua-Hot Heating
Systems Inc. recommends CAMCO’s Boiler Antifreeze
-100°.
tivity characteristics. Although these types of antifreeze
products are considered less toxic and safer than ethylene
glycol for people, pets, and the environment, they are not
“Generally Recognized as Safe” (GRAS) rated by the FDA.
Therefore, they must be marked with a “harmful if swallowed” warning. This additional warning is required because these types of antifreeze products contain high levels
of chemical inhibitors. Due to their potentially hazardous
properties, they should never be used in the Aqua-Hot’s
Hydronic Heating System.
Antifreeze Types:
Antifreeze Mixture Water Quality:
The following information addresses the necessary usage of
a propylene glycol based “boiler “ type antifreeze in the Aqua-Hot. Propylene glycol is a safer alternative to the more
toxic ethylene glycol antifreeze; however, as mandated by
IAPMO (International Association of Plumbing and Mechanical Officials), only those propylene glycol based “boiler”
type antifreezes deemed “Generally Recognized as
Safe” (GRAS) by the FDA should be utilized.
Because of the significant impact various types of antifreeze
can have on a Hydronic heating system, including the level
of safety provided, it has been recognized that there is a need
to provide an explanation regarding two additional prominent types of antifreeze/coolant available. The following
information should be utilized as an educational means of
ensuring that the proper type of propylene glycol based antifreeze is selected:
RV & Marine Antifreeze:
These types of propylene glycol based antifreeze products
are formulated specifically for “winterizing” applications
only. Although RV & Marine antifreeze is often “Generally
Recognized as Safe” by the FDA, it should never be used in
the Aqua-Hot’s Hydronic Heating System. This type of antifreeze is not formulated to transfer heat, which is essential to
the heating system’s functionality and does not contain rust
inhibitors. Please note, however, that RV & Marine antifreeze can be utilized to winterize the Aqua-Hot’s domestic
water heating system.
Automotive Antifreeze/Coolant:
These types of propylene glycol based antifreeze products
are formulated specifically to protect automotive engines
against corrosion, freezing temperatures, and overheating.
They also have excellent heat transfer and thermal conduc-
In order to ensure maximum performance and longevity of
an Aqua-Hot heating system’s boiler tank and associated
components, it has been determined that there is a need to
use distilled, de-ionized, or soft water in combination with
concentrated propylene glycol for the Aqua-Hot’s antifreeze
and water heating solution,. Please note that this is only necessary when mixing concentrated propylene glycol antifreeze
with water; suppliers of pre-mixed antifreeze are responsible
for the use of high-quality (distilled, de-ionized, or soft) water when preparing their antifreeze for sale.
Hard water possesses a high-level of calcium and magnesium
ions, which deplete the propylene glycol antifreeze’s corrosion inhibitors. This, in turn, causes the antifreeze and water
heating solution to begin turning acidic, which can corrode
the Aqua-Hot’s boiler tank and associated components prematurely. Therefore, concentrated propylene glycol should be
diluted with distilled, de-ionized, or soft water that is 80
PPM or less in total hardness. The local water agency should
have up-to-date water quality reports that should indicate if
the local tap water is within this guideline.
Antifreeze Terms and Mixture Ratio:
The following information addresses the process of selecting
an antifreeze and water mixture ratio that provides adequate
freeze, boiling, and rust/anti-corrosive protection. A 50/50
mixture ratio is recommended, which will result in a freeze
point of approximately -28°F and a boil point of approximately 222°F.
The following information should be utilized for the purpose
of clarifying some terms commonly associated with antifreeze.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 2: AQUA-HOT 600 SERIES OVERVIEW
Freeze Point and Burst Point:
Summary:
Antifreeze lowers the freezing point of any liquid, to which it
has been added, by preventing the formation of ice crystals;
however, as the ambient temperature continues to decline,
the water in the solution will attempt to attain a solid state.
The point in which the water begins to solidify is termed the
“Freeze Point.” Although the water in the solution has begun to freeze, producing a “slushy” consistency, the antifreeze in the solution will continue to combat the normal
expansion of the solution as it freezes. The point in which
the solution can begin to expand, due to colder temperatures,
is called the “burst point.” Once the solution reaches the
burst point, the potential is present for ruptured pipes to exist. The burst point of the antifreeze and water heating solution is dependent upon the brand of propylene glycol employed.
Antifreeze has three basic functions: freeze protection, boilover protection, and anti-corrosion and rust protection.
Antifreeze is also primarily responsible for heat transfer
characteristics. Therefore, as water is an excellent heat conductor, it is added to the mixture. A 50/50 solution of propylene glycol antifreeze and water is recommended to provide the best performance combination of the aforementioned functions. If excess propylene glycol exists within an
antifreeze and water heating solution, the water’s heat absorption properties are compromised, which could ultimately
inhibit the Aqua-Hot from providing adequate domestic hot
water and interior heating.
Additionally, if the antifreeze and water heating solution
contains over 70 percent antifreeze, the freezing point is actually raised, resulting in less freeze protection.
Boiling Point:
The Aqua-Hot utilizes the antifreeze and water heating solution as a transportation means for the heat produced from the
internal processes. The antifreeze absorbs the heat created
until its boiling point is reached; it is at this point that the
liquid turns to a gas and is expelled to prevent the heating
system from overheating. Each time the boiling point is
reached, a loss of efficiency occurs because the heat produced is expelled rather than used for the function of the
heating system. Therefore, a higher boiling point is desired
in order to combat the loss of efficiency, which allows the
antifreeze to transport the heat created from the internal process throughout the motor home where it can be used productively rather than dissipating due to its change from a
liquid to a gas.
Rust and Anti-Corrosive Inhibitors:
Another major function of antifreeze is to provide protection
to the internal metal components of the Aqua-Hot Hydronic
heating system from corrosion and rust. Antifreeze is able to
perform this function by the addition of rust- and anticorrosive inhibitors, which are designed specifically to activate in a water solution.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 3: INTERIOR SWITCH PANEL
The interior switch panel is used to control the two potential
heating sources for the Aqua-Hot’s boiler tank, as well as to
control the engine preheat feature. When a switch is activated, the indicator light on the switch will illuminate.
Diesel-Burner Switch:
When the diesel-burner switch is in the on position, and any
time the control thermostat tells the electronic controller that
heat is needed for the boiler tank, the diesel-burner will respond by firing up and providing heat. A cold boiler tank
can expect to be brought to operating temperature by the
diesel-burner in approximately 10 to 20 minutes. In order to
obtain continuous hot water, the diesel-burner switch must
be activated.
NOTE: If the diesel-burner fails to ignite, the diesel burner
status light will go out, indicating to the customer the burner has gone into a default. To reset the default, the diesel
burner switch must be turned off for 5 seconds and then
turned back on.
Additionally, the diesel-burner switch can be used to reset a
low-voltage condition. This is accomplished by turning off
the diesel-burner switch for 30 seconds, then turning it back
on.
Engine Preheat Switch:
The engine preheat switch activates the engine preheat
pump, which draws the motor home’s engine coolant
through the boiler tank to heat it before returning it to the
engine block to transfer the heat there. Either the dieselburner switch or the electric element switch must also be
activated in order for the engine preheat feature to function.
The engine preheat switch does not need to be activated for
the motor-aide feature to work and should be shut off when
traveling.
Electric Element Switch:
NOTE: The Electric Heating Element (s) is the Aqua-Hot’s
secondary heat source for heating both the interior and/or
the domestic hot water during low heating demand situations (such as when moderate ambient temperatures exist
and/or when there is a low demand for domestic hot water).
This feature is only operational whenever the Motor Home
is connected to VAC power or when the generator is operating
When the motor home is plugged into an AC power source
(e.g., shore power, generator, etc.) and the electric element
switch is on, the electric heating element will be used to provide heat to the boiler tank if the need arises. A cold boiler
tank can expect to be brought to operating temperature by the
electric heating element in approximately 1 to 2 hours. The
electric element, alone, will not be able to provide continuous hot water.
Figure 6
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 3: INTERIOR SWITCH PANEL
AHE-600-D03 - Electric Element (s)
AHE-675-D03 - Electric Element (s)
Function:
The “Electric switch, in conjunction with the “High/Low”
switch, activates the Aqua-Hot’s Electric Heating
Element (s), thereby illuminating the indicator light on the
switch; reference Figure 7.
Function:
The “Electric switch, in conjunction with the “High/Low”
switch, activates the Aqua-Hot’s Electric Heating
Element (s), thereby illuminating the indicator light on the
switch; reference Figure 7.
Low:
The process of moving the “High/Low” switch to the “Low”
position, in conjunction with the activation of the “Electric”
switch, allows one 120 VAC/2000 Watt Electric Heating
Element to supply heat to the Aqua-hot’s Boiler tank. The
120 VAC/2000 Watt Electric heating Element will heat the
Aqua-Hot System to the maximum operating temperature
(190°F (+/-5°)) in approximately 1-2 hours.
Low:
The process of moving the “High/Low” switch to the “Low”
position, in conjunction with the activation of the “Electric”
switch, allows the 120 VAC/2000 Watt Electric Heating Element to supply heat to the Aqua-hot’s Boiler tank. The 120
VAC/2000 Watt Electric heating Element will heat the Aqua
-Hot System to the maximum operating temperature(190°F
(+/-5°)) in approximately 1-2 hours.
High:
The process of moving the “High/Low” switch to the
“High” position, in conjunction with the activation of the
“Electric” switch, allows both 120 VAC/2000 Watt Electric
Heating Elements to supply heat to the Aqua-Hot’s Boiler
Tank. These two 120 VAC/2000 Watt Electric Heating Elements will heat the Aqua-Hot System to the maximum operating temperature (190°F (+/-5°)) in approximately 0.5 - 1
hour.
High:
The process of moving the “High/Low” switch to the
“High” position, in conjunction with the activation of the
“Electric” switch, allows both the 120 VAC/2000 Watt and
the 240 VAC/4500 Watt Electric Heating Elements to supply
heat to the Aqua-Hot’s Boiler Tank. The 120 VAC/2000
Watt and the 240 VAC/4500 Watt Electric Heating Elements
will heat the Aqua-Hot System to the maximum operating
temperature (190°F (+/-5°)) in approximately 0.5 - 1 hour.
Figure 7
Diesel-Burner Switch must be ON
to obtain a continuous supply of
hot water.
Activate the electric element switch and place
the high/low switch on HIGH for maximum
hot water capacity
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 18 —
SECTION 3: INTERIOR SWITCH PANEL
Figure 8
For Heaters Manufactured Before January 2011
For Heaters Manufactured After January 2011
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 19 —
SECTION 4: EXHAUST SYSTEM REQUIREMENTS
Because the Aqua-Hot’s exhaust is hot and must be kept
away from any heat-sensitive material, the exhaust system
should be checked to ensure that it continues to meet the
following requirements:

The exhaust must not be directed downward as a fire
could result when parked in dry, grassy areas.

The exhaust must not terminate underneath the vehicle,
underneath an openable window or vent, in the awning
area of the motor home (if applicable), or near slide-out
areas.

The exhaust must be able to freely exit away from the
vehicle without any obstructions.

Two-inch standard automotive-type exhaust piping
should be used with a maximum of two 90-degree pipe
bends and should not exceed 20 feet.

The 3-inch and 4-inch black-pipe nipples and the exhaust elbow - originally supplied with the Aqua-Hot,
must be present.
Figure 9
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 20 —
SECTION 5: AQUA-HOT COMPONENTS
If continuity is not present with the button pushed in,
follow the instructions in this section to replace the
Interlock Switch.
This section details various components of the Aqua-Hot
that may require troubleshooting and/or replacement in
the event of a malfunction. The diesel-burner and its
components are detailed in Section 10 of this manual.
Replacement Procedure:
Replacement parts can be ordered through Aqua-Hot’s
Web site at www.aquahot.com or by calling 1-800-6854298.
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
If additional assistance is needed, the Technical Support
Team can also be reached, Monday through Friday, from
7:00 AM to 4:00 PM Mountain Standard Time at 1-800685-4298.
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Disconnect the Interlock Switch’s wires by pulling the
quick connectors from the switch’s spade terminals.
2.
Release the Interlock Switch from the Aqua-Hot cabinet
by pushing in on the locking tabs and pulling the
Interlock Switch.
3.
The Interlock Switch is a safety device designed to ensure
that the Aqua-Hot’s access cover is securely installed before
allowing the diesel-burner to operate.
Remove the defective Interlock Switch from the AquaHot.
4.
Install the replacement Interlock Switch onto the
Aqua-Hot ensuring that the locking tabs snap into place.
Troubleshoot the Interlock Switch if the following condition
has occurred:
5.
Connect the Aqua-Hot’s wires to the replacement
Interlock Switch with yellow wire #24 connected to the
terminal labeled “NO” and yellow wire #25 connected
to the terminal labeled “COM.”
Sensors/Switches
Interlock Switch:


The diesel-burner fails to operate.
The diesel-burner switch light does not illuminate.
Troubleshooting:
NOTE: The interlock switch will prevent the diesel-burner
from operating without the access cover intact;
therefore, the switch will need to be manually
pressed during testing for the switch’s functionality.
1.
Turn the diesel-burner switch on from the interior switch
panel and ensure that the boiler tank has sufficiently
cooled in order to require heat from the diesel-burner.
2.
Verify that the “Heating Status” and “Diesel-Burner
Status” indicator lights are illuminated on the electronic
controller.
3.
Disconnect the two yellow wires from the interlock
switch noting that wire #24 is connected to the terminal
labeled “NO” and wire #25 is connected to the terminal
labeled “COM.”
4.
Using a digital volt meter, set to check for continuity,
check the interlock switch for continuity while the
button is pushed in.
NOTE: If the Interlock Switch’s wires are reversed, the
Interlock Switch will only allow the diesel-burner to
operate when the access cover is removed and the
button on the switch is released.
Figure 10
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 21 —
SECTION 5: AQUA-HOT COMPONENTS
jumper wire is installed, inspect the wire harness for
damaged or severed wires. If no wires are found to
be damaged or severed, follow the instructions in
this section to replace the fluid-level sensor.
Fluid-Level Sensor:
The Fluid-Level Sensor monitors the level of antifreeze and
water heating solution within the Aqua-Hot’s boiler tank to
ensure that an adequate volume exists.
If, however, the “Low Tank-Level Cutoff” indicator
light continues to illuminate once the jumper wire is
installed, follow the instructions in this manual to
replace the electronic controller.
Troubleshoot the Fluid-Level Sensor if one of the following
conditions has occurred:

The diesel-burner and/or electric heating element fails to
operate.
Replacement Procedure:

The Aqua-Hot fails to operate and the “Low Tank-Level
Cutoff” indicator light on the electronic controller is
illuminated.
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
Troubleshooting:
1.
Verify that the Aqua-Hot’s boiler tank is full of the antifreeze and water heating solution.
2.
Verify that the wire connector is securely plugged into
the fluid-level sensor and secured with the attached clip.
3.
Verify that the fluid-level sensor’s wires are securely
installed in the terminal strip on the wire harness, as well
as tightly fastened to the electronic controller.
The fluid-level sensor requires power to operate and
possesses a third wire for power (#17), which advances
from the sensor to join the red #1 wire on the “PUMP
3+” terminal on the electronic controller’s JP3 plug.
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected. Also, because this replacement procedure will involve the boiler tank and the potential for hot coolant, be
sure the heater has adequately cooled.
2.
Drain the antifreeze and water heating solution from the
Aqua-Hot’s boiler tank using the drain valve.
3.
Remove the Thermostat Access Panel
4.
Disconnect the fluid-level sensor’s wires by releasing
the clip securing the plug to the sensor and pulling the
plug away from the sensor. Reference Figure 11 for
location.
5.
Using a 7/8” wrench, unscrew the fluid-level sensor
from the Aqua-Hot’s boiler tank. It may be necessary to
use a 7/8” Crow’s Foot wrench.
6.
Add a liquid thread sealant (such as Loctite®) to the
threads of the replacement fluid-level sensor.
7.
Screw the replacement fluid-level sensor into the port on
the Aqua-Hot’s boiler tank and tighten with a wrench.
8.
Plug the fluid-level sensor’s wires into the replacement
sensor and secure with the clip.
9.
Refill the Aqua-Hot’s boiler tank with the antifreeze and
water heating solution.
NOTE: If pump number 3 shorts out, i.e. indicator light is
red, it will cause the Low Tank-Level Cutoff light to illuminate red as well.
4.
Verify the functionality of the fluid-level sensor by
completing the following:
A. Remove the faceplate from the electronic controller.
B. Install a jumper wire on the JP3 plug, between pins
15 and 16 (between “LWCO-I” and “LWCO-O”) on
the electronic controller in order to bypass the fluidlevel sensor.
If the “Low Tank-Level Cutoff” indicator light on
the electronic controller extinguishes when the
10. Reinstall the Thermostat Access Panel
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 22 —
SECTION 5: AQUA-HOT COMPONENTS
Figure 11
Fluid Level Sensor
Thermostats
Control Thermostat:
The control thermostat is installed into the Aqua-Hot’s boiler
tank and monitors the temperature of the antifreeze and water heating solution to determine when it is at operating temperature and when it requires heat. The Aqua-Hot is considered to be at operating temperature between 158°F and
190°F.
Troubleshoot the control thermostat if one of the following
conditions has occurred:



There is a lack of hot domestic water and interior heat.
The heating Status light does not illuminate on the electronic controller, when the Aqua-Hot is below 158° F.
Excessive Blue or white smoke is expelled from the exhaust.
Troubleshooting:
1.
2.
Turn the diesel-burner and electric element switches on
the interior switch panel on, and check the electronic
controller to ensure that the “Electric Heating Element
Status” and “Diesel-Burner Status” indicator lights are
illuminated.
Verify that the “Heating Status” indicator light on the
electronic controller is illuminated as it should be whenever the Aqua-Hot is below the operating temperature
range of 158°F.
If the “Heating Status” indicator light is not illuminated,
check the following:
A. Verify that the temperature of the boiler tank has
fallen below the 158°F minimum operating temperature by checking with a digital thermometer.
B. Disconnect the control thermostat’s wires from their
connections, and, using an ohmmeter, check for
continuity.
If there is no continuity, follow the instructions in
this section for replacing the control thermostat.
If continuity exists, complete the following:
a.
Inspect the control thermostat’s wiring and
connections.
b.
Install a jumper wire on the JP3 plug, between
pins 13 and 14 (“TSTAT-I” and “TSTAT-O”)
on the electronic controller in order to bypass
the control thermostat.
NOTE: The diesel-burner and/or electric element switch
must be in the on position for the “Heating Status” indicator
light on the electronic controller to illuminate.
If the “Heating Status” indicator light on the electronic
controller does not illuminate with the jumper wire installed, follow the instructions in this manual to replace
the electronic controller.
NOTE: If the Control Thermostat is intermittent, it may
result in the Heating status light flickering off and on, which
would cause the diesel burner to blue/white smoke.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 23 —
SECTION 5: AQUA-HOT COMPONENTS
Control Thermostat Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPLIES AND/OR TO
ALLOW THE HEATER TO COOL BEFORE SERVICING COULD
5.
Using a 7/8 socket, unscrew the control thermostat from
the Aqua-Hot’s boiler tank.
6.
Wrap the threads of the replacement control thermostat
with a thread sealing tape.
7.
Screw the replacement control thermostat into the port
on the Aqua-Hot’s boiler tank and tighten securely with
a 7/8 socket.
8.
Connect the replacement control thermostat’s wires in
the same configuration as the removed control thermostat’s wires.
9.
Refill the Aqua-Hot’s boiler tank with the antifreeze and
water heating solution.
CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
2.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected. Also, because this replacement procedure will involve the boiler tank and the potential for hot coolant, be
sure the heater has adequately cooled.
Drain the antifreeze and water heating solution from the
Aqua-Hot’s boiler tank using the drain valve.
3.
Remove the Thermostat Access Panel
4.
Disconnect the defective control thermostat’s wires by
separating the quick-disconnect terminals. Reference
Figure 12 for location.
10. Re-install the Thermostat Access Panel
11. Test the Aqua-Hot for normal operation.
Figure 12
185 °F Control Thermostat
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 24 —
SECTION 5: AQUA-HOT COMPONENTS
AC High-Limit Thermostat : Right Electric Element
NOTE: If the high-limit thermostats continue to trip, troubleshoot the control thermostat, and verify the boiler tank is
full of the antifreeze-water solution.
The AC high-limit thermostat serves as a safety measure in
the event that the electric heating element continues to operate after the maximum operating temperature is reached.
The high-limit thermostat allows the current for the heating
element to pass through it until the boiler tank reaches a temperature of 215°F. Should this temperature be reached, the
high-limit thermostat blocks the current to the element,
which prevents it from continuing to provide heat to the boiler tank.
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Troubleshoot the AC high-limit thermostat for the right electric element if the following condition has occurred:
Ensure that the Aqua-Hot has been completely shut
down and that all power supplies have been disconnected.
2.
Remove the AC access cover.

3.
If applicable, remove the heat shrink insulation covering
the wires and terminals on the defective high-limit thermostat.
4.
Remove the two wires from the defective high-limit
thermostat by pulling firmly on the wires.
5.
Using a 5/8 wrench or socket, remove the defective high
-limit thermostat from the Aqua-Hot’s boiler tank.
6.
Install the replacement high-limit thermostat into the
port on the Aqua-Hot’s boiler tank and finger-tighten
only (15 in/lbs).
7.
Connect the wires removed from the defective high-limit
thermostat to the replacement high-limit thermostat.
8.
Secure the Thermostat Access Panel cover back into
place.
The right electric heating element fails to operate.
Troubleshooting:
1.
Disconnect all power supplies.
2.
Remove the Thermostat Access Panel.
3.
Verify that the boiler tank’s temperature is below 215°F.
4.
Locate the AC high-limit thermostat for the Right Electric element and remove its wires.
NOTE: The location of the AC high limit thermostat may
vary in location, from Figure 13.
5.
Using an ohmmeter, check the thermostat for continuity.
If there is no continuity, press the white reset button on
the thermostat and re-check for continuity.
9. Test for proper operation.
If continuity is still not present after the reset button has
been pressed, follow the instructions in this section to
replace the AC high-limit thermostat.
Figure 13
215 °F A.C.
High Limit
Thermostat
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 25 —
SECTION 5: AQUA-HOT COMPONENTS
AC High-Limit Thermostat: Left Electric
Element
NOTE: If the high-limit thermostats continue to trip, troubleshoot the control thermostat, and verify the boiler tank is
full of the antifreeze-water solution.
The AC high-limit thermostat serves as a safety measure in
the event that the electric heating element continues to operate after the maximum operating temperature is reached.
The high-limit thermostat allows the current for the heating
element to pass through it until the boiler tank reaches a temperature of 215°F. Should this temperature be reached, the
high-limit thermostat blocks the current to the element,
which prevents it from continuing to provide heat to the boiler tank.
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Troubleshoot the AC high-limit thermostat for the Left Electric element if the following condition has occurred:
Ensure that the Aqua-Hot has been completely shut
down and that all power supplies have been disconnected.
2.
Remove the AC access cover.

3.
If applicable, remove the heat shrink insulation covering
the wires and terminals on the defective high-limit thermostat.
4.
Remove the two wires from the defective high-limit
thermostat by pulling firmly on the wires.
5.
Using a 5/8 wrench or socket, remove the defective high
-limit thermostat from the Aqua-Hot’s boiler tank.
6.
Install the replacement high-limit thermostat into the
port on the Aqua-Hot’s boiler tank and finger-tighten
only (15 in/lbs).
7.
Connect the wires removed from the defective high-limit
thermostat to the replacement high-limit thermostat.
8.
Secure the Thermostat Access Panel back into place.
The Left Electric Heating Element fails to operate.
Troubleshooting:
1.
Disconnect all power supplies.
2.
Remove Thermostat Access Panel
3.
Verify that the boiler tank’s temperature is below 215°F.
4.
Locate the AC high-limit thermostat for the left electric
element and remove its wires.
NOTE: The location of the AC high limit thermostat may
vary in location, from Figure 14.
5.
Using an ohmmeter, check the thermostat for continuity.
If there is no continuity, press the white reset button on
the thermostat and re-check for continuity.
9. Test for proper operation.
If continuity is still not present after the reset button has
been pressed, follow the instructions in this section to
replace the AC high-limit thermostat.
Figure 14
215 °F A.C.
High Limit
Thermostat
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 26 —
SECTION 5: AQUA-HOT COMPONENTS
B. Disconnect the wires from each thermostat and recheck each thermostat for continuity, as well as
each of the thermostats’ individual wires.
DC High-Limit Thermostats:
The DC high-limit thermostats (2) serve as a safety measure
in the event that the diesel-burner continues to operate after
the maximum operating temperature is reached. The highlimit thermostats allow the current for the diesel-burner to
pass through them until the boiler tank reaches a temperature
of 215°F. Should this temperature be reached, the high-limit
thermostat blocks the current to the diesel-burner’s fuel solenoid valve, which prevents the diesel-burner from operating.
Troubleshoot the DC high-limit thermostat if the following
condition has occurred:

The fuel solenoid on the diesel-burner fails to operate.
If an individual wire does not have continuity, that
wire must be replaced.
If a thermostat with the wires removed that has been
reset does not have continuity, follow the instructions in this section to replace the high-limit thermostat.
NOTE: If the high-limit thermostats continue to trip, troubleshoot the control thermostat, and verify the boiler tank is
full of the antifreeze-water solution.
Replacement Procedure:
Troubleshooting:
1.
Remove the Thermostat Access Panel
2.
Place a jumper wire between the blue and purple wires
on the diesel-burner’s wire harness to bypass the high
limit thermostats. Check the Aqua-Hot for normal
operation.
NOTE: Bypassing the high-limit thermostats is for testing
only and must not be used for the Aqua-Hot’s normal
functioning.
3.
Disconnect the DC high-limit thermostats’ wires, then,
using an ohmmeter, check each thermostat for continuity.
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been
disconnected.
2.
Remove the Thermostat Access Panel
3.
Remove the two wires from the defective high-limit
thermostat by pulling firmly on the wires.
4.
Using a 5/8 wrench or socket, remove the defective high
-limit thermostat from the Aqua-Hot’s boiler tank.
5.
Install the replacement high-limit thermostat into the
port on the Aqua-Hot’s boiler tank and finger-tighten
only (15 in/lbs).
6.
Connect the wires removed from the defective high-limit
thermostat to the replacement high-limit thermostat.
7.
Secure the Thermostat Access Panel in place.
If there is no continuity, complete the following:
A. Press the white reset button on the high-limit thermostat, then re-check for continuity.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 27 —
SECTION 5: AQUA-HOT COMPONENTS
215 °F D.C.
High Limit
Thermostat
Figure 15
Valves
Check Valve:
Check valves are installed into the zone outlet ports for each
heating loop to ensure that the antifreeze and water heating
solution only flows in one direction. If the heating solution
attempts to backflow into the boiler tank, the check valve
closes to prevent that from happening.
Troubleshoot the check valves if the following condition has
occurred:

There is a lack of interior heat in a particular zone.
2.
With the circulation pump operating, tap on the check
valve and wait five minutes to evaluate if interior heat is
now present.
If interior heat is present after tapping the check valve,
the check valve was stuck closed and no further action is
necessary.
NOTE: Storing the motor home for an extended period of
time can cause the check valves to stick. If, after the initial
release of the stuck check valve, it continues to stick, follow
the instructions in this section to replace the check valve.
Troubleshooting:
1.
Verify that the heating zone is operating properly by
checking the following:
A. Check the electronic controller to insure that both
the “Heating Zone Status” and corresponding pump
status (“Pump #1”, “Pump #2”, or “Pump #3) indicator lights are illuminated green.
3.
Check the Aqua-Hot’s antifreeze and water heating solution’s ratio of water to propylene glycol. The mixture
ratio should be approximately 50/50. If the solution is
comprised fully of antifreeze (100%), the check valves
will continue to stick.
B. Check the circulation pump for operation by visually inspecting it for rotation of the pump.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 28 —
SECTION 5: AQUA-HOT COMPONENTS
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
6.
Remove the hose barb and the 1/2 inch coupler from the
defective check valve.
7.
Clean the hose barb and coupler, then wrap the hose
barb and the 1/2 inch coupler pipe threads with Teflon
tape.
8.
Install the hose barb and 1/2 inch coupler on the replacement check valve, ensuring that they are installed
properly with the hose barb on the arrow side of the
check valve.
9.
Install the replacement check valve onto the Aqua-Hot’s
boiler tank. The arrow on the check valve must point
away from the boiler tank.
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected. Also, because this replacement procedure will involve the boiler tank and the potential for hot coolant, be
sure the heater has adequately cooled.
2.
Drain the antifreeze and water heating solution from the
Aqua-Hot’s boiler tank using the drain valve.
3.
Using constant tension pliers, loosen and slide back the
constant tension clamp securing the hose to the defective
check valve.
10. Slide the hose back onto the replacement pump and set
the constant tension clamp back into place.
4.
Remove the hose from the defective check valve.
11. Refill the Aqua-Hot’s boiler tank with the antifreeze and
water heating solution.
5.
Unscrew the defective check valve from the Aqua-Hot’s
boiler tank.
Figure 16
Check Valve
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 29 —
SECTION 5: AQUA-HOT COMPONENTS
Tempering Valve:
3.
Remove both the Domestic Water access panel and the
Thermostat Access Panel.
4.
Disconnect the motor home’s water lines from the
tempering valve assembly.
5.
Loosen and Remove the Bulk Head Fitting Nut, Located
on the top of the heater, for the Hot output water.
6.
Disconnect both the Hot and Cold Pex pipe fittings from
the boiler tank.
NOTE: Prior to trouble shooting the tempering valve, it is
recommended to review the Lack of Hot Water Trouble
Shooting guide in section 11.
7.
Remove the tempering valve assembly from the AquaHot by sliding it out the thermostat access cover area.
1.
Inspect the tempering valve to ensure that it is not
leaking.
8.
Remove all fittings from the defective tempering valve,
and clean to be reused.
2.
Test the temperature of the hot water using a digital
thermometer at one of the hot water faucets. Water
Temperature should range between 115° F - 123° F. If
the proper range cannot be set follow the instructions in
this section to replace the tempering valve.
9.
Wrap the threads of the brass fittings with a thread seal
tape, on the side that screws into the tempering valve,
and Install the brass fittings onto the replacement tempering valve.
The tempering valve for the Aqua-Hot mixes the heated domestic water from the boiler tank with cold domestic water at
a preset ratio to reduce the risk of scalding.
Troubleshoot the tempering valve if the following condition
has occurred:

There is a lack of hot domestic water.
Troubleshooting:
3.
Test the tempering valve’s functionality by turning the
knob.
If the tempering valve’s knob does not turn freely, follow the instructions in this section to replace the tempering valve.
10. Install the replacement tempering valve onto the AquaHot by sliding in through the thermostat access cover.
11. Reconnect the Pex pipe fittings on the tempering valve
assembly to the Aqua-Hot. Be sure to inspect the rubber
seals and replace if necessary.
Replacement Procedure:
12. Reconnect the motor home’s water lines to the tempering valve assembly.
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
13. Turn the motor home’s water pump back on and check
for leaks and the presence of hot domestic water.
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Turn the motor home’s water pump off.
2.
Drain the water pressure by opening the faucets and
allowing the water to drain.
14. Verify that the replacement tempering valve has been set
to the proper setting by taking a digital thermometer to
a hot water faucet and set the water temperature between
115*F - 123*F.
15. Secure both the Domestic Water Access Panel, and the
Thermostat Access Panel in place.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 30 —
SECTION 5: AQUA-HOT COMPONENTS
Figure 17
Mixer Valve
Assembly
Hot Water Outlet Port
Cold Water inlet Port
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 31 —
SECTION 5: AQUA-HOT COMPONENTS
Pumps
Circulation Pumps #1, #2 and #3:
The circulation pumps first draw the heated antifreeze and
water heating solution from the Aqua-Hot’s boiler tank, then
propel it through the Hydronic heating system’s interior heat
plumbing.
Troubleshoot the circulation pumps if the following condition has occurred:
B. With the jumper wire installed, check the indicator
light corresponding to the pump not operating.
If the indicator light illuminates green, complete the
following:
A. Using a voltmeter, check for 12 volts of DC power
on the JP3 plug pins corresponding to the pump not
operating.

The circulation pump is not operating and the “Low
Temp Cutoff Status” indicator light is illuminated on the
electronic controller.
If 12 volts of DC power are not present, follow the
instructions in this manual to replace the electronic
controller.

The Zone Pump indicator light illuminates red on the
electronic controller.
B. Disconnect the circulation pump’s wires from the
wiring harness, then, using a voltmeter, check the
wires on the wiring harness for 12 volts of DC power.
Troubleshooting:
1.
Verify that the “Low Temp Cutoff Status” indicator
light on the electronic controller is illuminated, as it will
be continuously with the 600 Series Aqua-Hot.
2.
Turn on the interior room thermostat corresponding to
the circulation pump not operating (heating zone 1 operates with circulation pump #1, heating zones 2,3,and 4
operate with circulation pump #2 and heating zone 5
operates with circulation pump #3). Check the corresponding “Heating Zone Status” indicator lights on the
electronic controller for illumination.
If the “Heating Zone Status” indicator light does not
illuminate, complete the following:
A. Install a jumper wire on the JP1 plug between the
pins corresponding to the room thermostat operating
the circulation pump that is not operating. Reference the wiring diagram in Appendix A. This will
bypass the room thermostat.
When the “Heating Zone Status” indicator light
illuminates on the electronic controller, the corresponding “Pump #1” and/or “Pump #2” and/or
“Pump #3” indicator light should illuminate as well.
If 12 volts of DC power are present at the wiring
harness, follow the instructions in this section to
replace the circulation pump.
NOTE: The circulation pump can be tested by connecting
it to an external 12 Volt-DC source to verify that the pump
is defective.
If the indicator light illuminates red, complete the following:
A. Disconnect the circulation pump’s wires.
If the indicator light turns green with the circulation
pump disconnected, follow the instructions in this
section to replace the circulation pump.
If the indicator light remains red with the circulation
pump disconnected, check the wiring for damage.
If no damage is found, follow the instructions in this
manual to replace the electronic controller.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 5: AQUA-HOT COMPONENTS
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
5.
Remove the hoses from the defective circulation pump.
6.
Release the pump from the mounting bracket by pulling
on each Nylatch plunger, then remove the defective
pump from the Aqua-Hot.
7.
Slide the hoses back onto the replacement pump and set
the constant tension clamps back into place.
8.
Install the replacement pump onto the mounting bracket
by aligning the Nylatch plungers to their respective
holes and pushing the plungers in to secure the pump to
the bracket.
9.
Reconnect the wires on the replacement pump to the
wire harness on the heater by uniting the red quickdisconnect terminals.
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected. Also, because this replacement procedure will involve the potential for hot coolant, be sure the heater is
adequately cooled.
2.
Drain the antifreeze and water heating solution from the
Aqua-Hot’s boiler tank using the drain valve.
3.
Disconnect the defective circulation pump’s wires by
separating the quick-disconnect terminals.
4.
Using constant tension pliers, loosen and slide back the
constant tension clamps securing the hoses to the circulation pump.
10. Refill the Aqua-Hot’s boiler tank with the antifreeze and
water heating solution.
11. Test the Aqua-Hot for normal operation.
Figure 18
Zone 1
Circulation Pump
Zone 3
Circulation Pump
Zone 2
Circulation Pump
Nylatch
Plunger
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 5: AQUA-HOT COMPONENTS
Pumps
Engine Preheat Pump:
A. Verify that the low temperature cutoff light and the
diesel burner/electric heating element status lights
are illuminated on the electronic controller.
The Engine Preheat circulation pump draws the cold antifreeze and water heating solution from the motor home’s
engine and then propels it through the Engine Preheat Heat
exchanger, located inside the boiler tank.
B. Using a jumper wire, bypass the engine preheat
switch on the JP3 plug, by connecting pins
Preheat-O and Preheat-I together.
If the engine preheat pump indicator light illuminates
with the jumper installed, inspect for loose wires. If no
loose wires are found, replace the engine preheat switch,
on the interior switch panel, inside the motor home.
Troubleshoot the Engine Preheat Pump if the following condition has occurred:


The Engine Preheat Pump is not operating, and the
Engine Preheat Switch on the Switch Panel inside the
motor Home is in the ON position and the “Low Temp
Cutoff Status” indicator light is illuminated on the
electronic controller.
The Engine Preheat Pump indicator light illuminates red
on the electronic controller.
Troubleshooting:
NOTE: Either the diesel-burner switch or the electric element switch must also be activated in order for the engine
preheat feature to function.

The Engine Preheat Pump is not operating, and the
Engine Preheat Switch on the Switch Panel inside
the motor Home is in the ON position and the “Low
Temp Cutoff Status” indicator light is illuminated
on the electronic controller.
1.
Verify that the “Low Temp Cutoff Status” indicator
light on the electronic controller is illuminated, as it will
be continuously with the 600 Series Aqua-Hot.
2.
Verify that the Engine Preheat Switch is in the ON position, on the interior switch panel inside the motor home.
Either the diesel burner switch or the electric element
switch must also be activated in order for the engine
preheat feature to function.
3.
On the electronic controller, verify that the engine
preheat pump light is illuminated.
If the engine preheat pump indicator light does not
illuminate, and the Low Temperature Cut-Off Light is
illuminated along with either the diesel or the electric
element status indicator light, follow the instructions in
this manual to replace the electronic controller.

The Engine Preheat Pump indicator light illuminates
green on the electronic controller but the pump is not
running.
A. Using a voltmeter, check for 12 volts of DC power
on the JP3 plug pins corresponding to the pump not
operating.
If 12 volts of DC power are not present, follow the
instructions in this manual to replace the electronic
controller.
B. Disconnect the engine preheat circulation pump’s
wires from the wiring harness, then, using a voltmeter, check the wires on the wiring harness for 12
volts of DC power.
If 12 volts of DC power are present at the wiring
harness, follow the instructions in this section to
replace the engine preheat circulation pump.
NOTE: The engine preheat circulation pump can be tested
by connecting it to an external 12 Volt-DC source to verify
that the pump is defective.
If the Engine preheat pump indicator light does not illuminate, complete the following:
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 34 —

The Engine Preheat Pump indicator light illuminates red
on the electronic controller.
3.
Disconnect the defective engine preheat pump’s wires by
separating the quick-disconnect terminals.
4.
Using constant tension pliers, loosen and slide back the
constant tension clamps securing the hoses to the engine
preheat pump.
5.
Remove the hoses from the defective engine preheat
pump.
6.
Release the pump from the mounting bracket by pulling on
each Nylatch plunger, then remove the defective pump
from the Aqua-Hot.
7.
Slide the hoses onto the replacement pump and set
the constant tension clamps back into place.
8.
Install the replacement pump onto the mounting bracket
by aligning the Nylatch plungers to their respective holes
and pushing the plungers in to secure the pump to the
bracket.
9.
Reconnect the wires on the replacement pump to the wire
harness on the heater by uniting the red quick-disconnect
terminals.
A. Disconnect the engine preheat circulation pump’s wires.
If the indicator light turns green with the engine preheat
circulation pump disconnected, follow the instructions in
this section to replace the engine preheat circulation
pump.
If the indicator light remains red with the circulation
pump disconnected, check the wiring for damage. If no
damage is found, follow the instructions in this manual
to replace the electronic controller.
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR TO
ALLOW THE HEATER TO COOL BEFORE SERVICING COULD
CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
2.
Ensure that the Aqua-Hot has been completely shut down
and that all power sources have been disconnected. Also,
because this replacement procedure will involve the potential
for hot coolant, be sure the heater is adequately cooled.
Using hose pinch off pliers, clamp both hoses attached to the
engine preheat pump, closed.
10. Remove the hose pinch off pliers previously installed on
both hoses.
11. Test the Aqua-Hot for normal operation.
Figure 19
Engine Preheat
Pump
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 35 —
SECTION 5: AQUA-HOT COMPONENTS
If the “Electric Heating Element Status” indicator
light illuminates on the electronic controller with
the jumper wire installed, check the Electric Element Switch, on the interior switch panel for functionality.
Electrical - AC
Electric Heating Element: Right
If the “Electric Heating Element Status” indicator
light does not illuminate on the electronic controller
with the jumper wire installed, follow the instructions in this manual to replace the electronic controller.
There are two different Models in the Aqua-Hot 600 Series.
The Aqua-Hot 600 has 2-2000 Watt 120 VAC electric heating elements. The Aqua-Hot 675 has 1-2000 Watt 120 VAC
electric heating element (Right), and 1-4500 Watt 240 VAC
electric heating element (Left)
If the “Heating Status” indicator light on the electronic
controller is not illuminated, complete the following:
The electric heating element uses AC power as an alternate
power source for heating the Aqua-Hot’s boiler tank.
A. Check the temperature of the Aqua-Hot’s boiler
tank.
Troubleshoot the electric heating element if the following
condition has occurred:

If the boiler tank temperature is below 158°F, troubleshoot the control thermostat.
There is a lack of hot domestic water and interior heat
when the electric element is selected as the heating
source.
If the boiler tank is above 158°F, the Aqua-Hot is at
operating temperature and requires no heat.
Troubleshooting:
NOTE: For continuous domestic hot water to be present,
the diesel-burner must be selected also as a heating source.
1.
2.
3. Verify the Electronic Controller is sending 12 Volt DC to
the A.C. Relay.
A. Using a volt meter check pins 11 & 12 (“AC
REL -” and “AC REL +”) for 12-Volt D.C on
the JP3 plug.
Verify that the motor home is either plugged into shore
power or that the generator is running to provide AC
power.
If 12 Volts of DC power are not present while the
“Electric Heating Element Status” and “Heating Status”
indicator lights on the electronic controller are illuminated, follow the instructions in this manual to replace the
electronic controller.
Verify that both the “Electric Heating Element Status”
and the “Heating Status” indicator lights on the electronic controller are illuminated.
If the “Electric Heating Element Status” indicator light
on the electronic controller is not illuminated, complete
the following:
A. Verify that the electric element switch on the interior switch panel is on.
B. Install a jumper wire on the JP2 plug, between pins
52 and 53 (“ELECT-O” and “ELECT-I”) on the
electronic controller to bypass the electric element
switch.
4.
If 12 Volts of DC power are present at the relay, complete the following follow the troubleshooting section
for the Right A.C. Relay in this section.
5.
Verify that the electric heating element is receiving adequate AC power by completing the following:
A. Remove the AC access cover.
B. Plug the Coach into shore power/turn generator on.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 36 —
SECTION 5: AQUA-HOT COMPONENTS
C. Using an AC voltmeter, verify that 110 volts of AC
power are present at the terminal block reference
figure 20. If there is not 110 VAC present at the
terminal block for the right electric element, there is
a problem inside the motor home.
2.
Drain the antifreeze and water heating solution from the
Aqua-Hot’s boiler tank using the drain valve.
3.
Remove the Electric Element access cover.
E. Check the electric element’s wires for continuity by
completing the following:
4.
Remove the two wires secured to the defective electric
heating element by releasing the screw terminals.
a.
Disconnect the motor home from shore power/
shut off generator.
5.
Using a 1-1/2 inch socket, remove the defective electric
heating element from the Aqua-Hot’s boiler tank.
b.
Disconnect the wires from the electric heating
element.
6.
c.
Disconnect the wires from the AC terminal
block.
Install the replacement 2000-watt electric heating element into the boiler tank ensuring that the “up” lettering
on the element is installed in the up position.
7.
Connect the wires removed from the defective electric
heating element to the replacement electric heating element and tighten the screw terminals.
8.
Reinstall the Electric Element access cover.
9.
Refill the Aqua-Hot’s boiler tank with the antifreeze and
water heating solution.
D. Using an amp-meter, verify that approximately 17
amps are present at the element’s wires.
d.
6.
down and that all power sources have been disconnected. Also, because this replacement procedure will involve the boiler tank and the potential for hot coolant, be
sure the heater has adequately cooled.
With the wires disconnected, check each individual wire for continuity.
Check the electric heating element for functionality by
completing the following:
A. Disconnect all power supplies.
B. Remove the Electric Element access cover.
C. Remove all wires from the electric heating element.
D. Using an ohmmeter, check the electric heating element for the proper ohms reading: 8-9 ohms.
Right Electric
Element Terminal
Block
Left Electric
Element Terminal
Block
If the ohms reading is not within spec, follow the
instructions in this section to replace the electric
heating element.
Replacement Procedure:
Figure 18
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut
Figure 20
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 37 —
SECTION 5: AQUA-HOT COMPONENTS
If the “Electric Heating Element Status” indicator
light illuminates on the electronic controller with
the jumper wire installed, check the Electric Element Switch, on the interior switch panel for functionality.
Electrical - AC
Electric Heating Element: Left
If the “Electric Heating Element Status” indicator
light does not illuminate on the electronic controller
with the jumper wire installed, follow the instructions in this manual to replace the electronic controller.
There are two different Models in the Aqua-Hot 600 Series.
The Aqua-Hot 600 has 2-2000 Watt 120 VAC electric heating elements. The Aqua-Hot 675 has 1-2000 Watt 120 VAC
electric heating element (Right), and 1-4500 Watt 240 VAC
electric heating element (Left)
If the “Heating Status” indicator light on the electronic
controller is not illuminated, complete the following:
The electric heating element uses AC power as an alternate
power source for heating the Aqua-Hot’s boiler tank.
A. Check the temperature of the Aqua-Hot’s boiler
tank.
If the boiler tank temperature is below 158°F, troubleshoot the control thermostat.
If the boiler tank is above 158°F, the Aqua-Hot is at
operating temperature and requires no heat.
Troubleshoot the left electric heating element if the following condition has occurred:

There is a lack of hot domestic water and interior heat
when the electric element is selected as the heating
source.
3. Verify the Electronic Controller is sending 12 Volt DC to
the A.C. Relay.
Troubleshooting:
NOTE: For continuous domestic hot water to be present,
the diesel-burner must be selected also as a heating source.
A. Using a volt meter check pins 11 & 12 (“AC
REL -” and “AC REL +”) for 12-Volt D.C on
the JP3 plug.
1.
Verify that the motor home is either plugged into shore
power or that the generator is running to provide AC
power.
2.
Verify that both the “Electric Heating Element Status”
and the “Heating Status” indicator lights on the electronic controller are illuminated.
If 12 Volts of DC power are not present while the
“Electric Heating Element Status” and “Heating Status”
indicator lights on the electronic controller are illuminated, follow the instructions in this manual to replace the
electronic controller.
4.
If the “Electric Heating Element Status” indicator light
on the electronic controller is not illuminated, complete
the following:
If 12 Volts of DC power are present at the relay, complete the following: follow the troubleshooting sections
for both the right and the Left A.C. Relays in this section.
5.
Verify that the electric heating element is receiving
adequate AC power by completing the following:
A. Verify that the electric element switch on the interior switch panel is on.
B. Install a jumper wire on the JP2 plug, between pins
52 and 53 (“ELECT-O” and “ELECT-I”) on the
electronic controller to bypass the electric element
switch.
A. Remove the VAC access cover.
B. Plug the Coach into shore power/turn generator on.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 38 —
SECTION 5: AQUA-HOT COMPONENTS
C. Using an AC voltmeter, verify the presence of AC
voltage at the terminal .
NOTE: The Aqua Hot 600 will have 120 VAC present at
the terminal block for the left electric element, while the
Aqua-hot 675 will have 240 VAC present at the terminal
block for the left electric element.
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected. Also, because this replacement procedure will involve the boiler tank and the potential for hot coolant, be
sure the heater has adequately cooled.
E. Check the electric element’s wires for continuity by
completing the following:
2.
Drain the antifreeze and water heating solution from the
Aqua-Hot’s boiler tank using the drain valve.
a.
Disconnect the motor home from shore power/
shut off generator.
3.
Follow the instructions for detaching the diesel burner in
section 9.
b.
Disconnect the wires from the electric heating
element.
4.
Remove the Electric Element access cover.
c.
Disconnect the wires from the AC terminal
block.
5.
Remove the two wires secured to the defective electric
heating element by releasing the screw terminals.
d.
Check the black and white wires at the terminal
block for continuity.
6.
Using a 1-1/2 inch socket, remove the defective electric
heating element from the Aqua-Hot’s boiler tank.
7.
Install the replacement 2000/4500-watt electric heating
element into the boiler tank ensuring that the “up” lettering on the element is installed in the up position.
8.
Connect the wires removed from the defective electric
heating element to the replacement electric heating element and tighten the screw terminals.
C. Remove all wires from the electric heating element.
9.
Reinstall the Electric Element access cover.
D. Using an ohmmeter, check the electric heating element for proper ohm reading
120 VAC 2000 Watt = 8 - 9 ohms
240 VAC 4500 Watt = 12.5 - 13 ohms
10. Follow the Directions for reattaching the diesel burner in
section 9.
D. Using an amp-meter, verify that amps are present at
the element’s wires.
120VAC 2000 Watt = Approximately 17 amps
240VAC 4500 Watt = Approximately 17 amps
4.
Replacement Procedure:
Check the electric heating element for functionality by
completing the following:
A. Disconnect all power supplies.
B. Remove the Electric Element access cover.
11. Refill the Aqua-Hot’s boiler tank with the antifreeze and
water heating solution.
If no continuity exists follow the instructions in this
section to replace the electric heating element.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 39 —
SECTION 5: AQUA-HOT COMPONENTS
Figure 21
Left Electric
Element
Right Electric
Element
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 40 —
SECTION 5: AQUA-HOT COMPONENTS
AC Relay: Right
A. Locate the AC wires connected to the AC relay
(pins 2 and 4), and remove the AC wires from the
relay.
The AC relay is an electrical device where the DC circuit
from the electronic controller determines whether the AC
power is permitted to flow to the electric heating element.
This allows the electronic controller to switch the electric
heating element on and off in conjunction with the interior
switch panel and control thermostat even though the electric
heating element is on a separate circuit.
Troubleshoot the Right AC relay if the following condition
has occurred:

The Right electric heating element fails to operate.
B. Using an ohmmeter, check the relay AC pins (2 and
4) for continuity.
If no continuity exists, follow the instructions in this
section to replace the AC relay.
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
Troubleshooting:
COULD CAUSE SERIUOS DAMAGE OR PERSONAL INJURY.
1.
Disconnect the AC power source to the motor home
(unplugging from shore power or shutting off the generator).
2.
Turn the electric element switch on the interior switch
panel on and check the electronic controller to ensure
that the “Electric Heating Element Status” and the
“Heating Status” indicator lights are illuminated.
3.
Using a voltmeter, check pins 11 and 12 (“AC Relay +”
and “AC Relay-”) on the JP3 plug for 12 Volts-DC.
1.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected.
2.
Also, ensure that the motor home is not connected to
shore power and that a generator is not connected during
this replacement procedure.
3.
Remove the Thermostat Access Cover.
4.
If 12 Volts of DC power are not present while the
“Electric Heating Element Status” and “Heating Status”
indicator lights on the electronic controller are illuminated, follow the instructions in this manual to replace the
electronic controller.
Release the wires from the defective AC relay by re
moving the corresponding screw terminals.
5.
Remove the defective relay by drilling the rivets that
hold the defective relay in place.
6.
Rivet the replacement AC relay to the AC access cover.
If 12 Volts of DC power are present, complete the following:
7.
Using the wiring diagram in Appendix A, connect the
wires previously removed to the replacement AC relay.
8.
Reinstall the Thermostat Access cover.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 41 —
SECTION 5: AQUA-HOT COMPONENTS
C. Locate the Left AC relay and check pin #1 for
12VDC +.
AC Relay: Left
The AC relay is an electrical device where the DC circuit
from the electronic controller determines whether the AC
power is permitted to flow to the electric heating element.
This allows the electronic controller to switch the electric
heating element on and off in conjunction with the interior
switch panel and control thermostat even though the electric
heating element is on a separate circuit.
If no 12VDC is present on the left relay, but there is
12VDC on the right relay troubleshoot the High/Low
switch.
A.
B.
C.
D.
Troubleshoot the Left AC relay if the following condition
has occurred:

The Left electric heating element fails to operate.
Troubleshooting:
D. Locate the AC wires connected to the AC relay
(pins 6 and 8), and remove the AC wires from the
relay.
There are two different Models in the Aqua-Hot 600 Series.
The Aqua-Hot 600 has 2-2000 Watt 120 VAC electric heating elements. The Aqua-Hot 675 has 1-2000 Watt 120 VAC
electric heating element (Right), and 1-4500 Watt 240 VAC
electric heating element (Left)
1.
Disconnect the AC power source to the motor home
(unplugging from shore power or shutting off the generator).
2.
Turn the both the electric element switch on the interior
switch panel on and turn the High/Low Switch to the
High position, and check the electronic controller to
ensure that the “Electric Heating Element Status” and
the “Heating Status” indicator lights are illuminated.
3.
Using a voltmeter, check pins 11 and 12 (“AC Relay +”
and “AC Relay-”) on the JP3 plug for 12 Volts-DC.
If 12 Volts of DC power are not present while the
“Electric Heating Element Status” and “Heating Status”
indicator lights on the electronic controller are illuminated, follow the instructions in this manual to replace the
electronic controller.
If 12 Volts of DC power are present, complete the following:
A. Locate the AC relay for the Right electric heating
element.
B. Check pins #1 for 12VDC +.
Locate the switch panel inside the motor home.
Remove the switch panel.
Locate the wires for the High/Low Switch.
Using a Voltmeter Verify 12VDC + on pin #1.
If voltage is present, turn the switch on, and
verify 12VDC + on pin #2. If no voltage is pre
sent on pin #2, with the High/Low switch in the
High position, the switch will need to be
replaced.
E. Using an ohmmeter, check the relay AC pins (6 and
8) for continuity.
If no continuity exists, follow the instructions in this
section to replace the AC relay.
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIUOS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected.
2.
Also, ensure that the motor home is not connected to
shore power and that a generator is not connected during
this replacement procedure.
3.
Remove the Thermostat Access cover.
4.
Release the wires from the defective AC relay by
removing the corresponding screw terminals.
5.
Remove the defective relay by drilling the rivets that
hold the defective relay in place.
6.
Rivet the replacement AC relay to the AC access cover.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 42 —
SECTION 5: AQUA-HOT COMPONENTS
AC Relay: Left (Continued)
7.
Using the wiring diagram in Appendix A, connect the
wires previously removed to the replacement AC relay.
8.
Secure the Thermostat Access cover in place
Figure 21
Left A.C.
Relay
Right A.C.
Relay
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 43 —
SECTION 6: ELECTRONIC CONTROLLER
Electronic Controller Overview
The electronic controller is an electronic circuit board that
controls the electrical functions of the Aqua-Hot heating
system. All wiring for the switch panel is connected to the
electronic controller, as well as the wiring circuitry from the
Aqua-Hot unit. Indicator lights on the front panel will illuminate red if there is a short circuit, overload, or fault condition within the system. It also will indicate when circuits are
functioning properly with a green indicator light.
Figure 22
Electronic Controller General Facts
Output Current Capacity
Nominal input voltage range ............................ 10.6V to 15V
Idle current ................................................... Approx. 15mA
Low voltage cutoff threshold .......................................10.0V
Under voltage lockout delay..................... Approx. 5 minutes
Input Load Currents
Zone thermostats (each) .................................. Approx. 4mA
Diesel-Burner switch ..................................... Approx. 12mA
Electric Element switch ................................... Approx. 4mA
Engine Preheat switch ..................................... Approx. 4mA
Low-level cutoff switch................................. Approx. 10mA
Control Thermostat ......................................... Approx. 8mA
Low-temperature cutoff switch ....................... Approx. 5mA
Zone fans (each) .................................................... 2.0A max.
Circulation pumps (each) ...................................... 2.0A max.
Engine preheat pump ............................................. 2.0A max.
AC relay ............................................................ 500mA max.
B4+ burner (Webasto) power ................................ 6.0A max.
B1+ burner master control ..................................... 2.0A max.
C1/C7 burner thermostat control ........................... 1.0A max.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 44 —
SECTION 6: ELECTRONIC CONTROLLER
Electronic Controller Features
Secondary 12 Volt-DC Battery Connection:
The electronic controller is equipped with two 12 Volt-DC
power source connections, which allow for a secondary 12
Volt-DC battery connection. This 12 Volt-DC battery connection is a product-safety feature that should be utilized
whenever the Aqua-Hot’s main 12 Volt-DC power supply is
connected to a battery disconnect switch. This feature will
ensure that the Aqua-Hot will be protected in the event that
the primary power is interrupted while the diesel-burner is
operating (e.g., during a burn-cycle). This secondary 12 Volt
-DC battery connection will ensure completion of the required 3-minute “purge cycle” of the Aqua-Hot’s dieselburner.
Figure 23
Terminal Strips with Screw-Type Fasteners:
Figure 24
The electronic controller uses terminal strips/plugs that are
equipped with screw-type fasteners, which are molded directly into the terminal strip/plug, itself. This will ensure a
positive mechanical connection between the electronic controller and all wire harnesses attached to it.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 45 —
SECTION 6: ELECTRONIC CONTROLLER
Low-Voltage Reset Feature:
Whenever the Aqua-Hot’s DC power is interrupted, for longer than 5 minutes, the “low battery voltage fault” red indicator light on the electronic controller will illuminate. Reset
the electronic controller by pressing the “low voltage reset”
button on the electronic controller (use a thin, straight, nonmetallic object to access the button through the faceplate) or
by turning off the diesel-burner switch on the interior switch
panel for approximately 30 seconds, then turning the switch
back on.
Figure 25
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 6: ELECTRONIC CONTROLLER
Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
6.
Snap the replacement electronic controller into the
mounting bracket.
7.
Ensure that the pin jumpers are properly configured for
an Aqua-Hot 600; reference information in this section
for proper pin-jumper configuration. Reference Figure
26.
8.
Install each terminal strip/plug back onto the electronic
controller and tighten the screws on the terminal strips/
plugs to secure them to the controller.
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
2.
Ensure that the Aqua-Hot has been completely shut
down and that all power sources have been disconnected.
Remove the faceplate from the electronic controller by
removing the four screws securing it to the mounting
bracket.
3.
Disconnect the positive, negative, and secondary power
(if applicable) wires from the electronic controller.
4.
Disconnect the four terminal strips/plugs from the electronic controller by loosening the screws on each strip/
plug and pulling each strip/plug away from the electronic controller.
5.
Remove the electronic controller from the mounting
bracket by unsnapping each corner.
Proper Pin Jumper Configuration:
1.
Verify that the pin jumpers are configured as in the illustration in this section. If the pin jumpers do not match
the illustration, the Aqua-Hot 600 will not function
properly.
2.
If the jumpers pins need to be reconfigured, simply tug
gently on the black cap covering the pins to pull the
black cap off.
3.
Reseat the cap on the pins appropriately as per the illustration.
NOTE: Check the terminal strips/plugs for loose wires and
tighten if loose.
9.
Connect the ground wire followed by the main 12 VoltDC power wire, then the secondary power wire (if applicable) to the appropriate screw terminals on the replacement electronic controller board. Reference Appendix A
for additional wiring information.
10. Reinstall the faceplate onto the electronic controller and
secure with the four screws previously removed.
Figure 26
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 47 —
SECTION 7: ELECTRONIC CONTROLLER INDICATOR LIGHTS
Electric Heating Element Status
NOTE: The Electric Heating Element Status indicator light
does not indicate AC Voltage at the Electric element. It
only indicates the status of the “DC” Side of the Electric
element, i.e. interior switch, electronic control board, relay.
This indicator light shows the status of the electric heating
element by illuminating green for on, red for fault, or by
turning off when the electric element switch is turned off.
If the light is off and the electric element switch on the interior switch panel is off, then the system is functioning correctly. If the indicator light is green and the electric element
switch on the interior switch panel is on, the system is also
functioning correctly.
If the light becomes red, the switch may be reset (after restoring voltage) by pressing the Low Voltage Reset Button on
the electronic controller with a long, thin, nonmetallic object,
or by turning the diesel-burner switch on the interior switch
panel off for 30 seconds, then turning it back on.
Low-Temp Cutoff Status
The Low Temp Cutoff thermostat does not function on the
Aqua-Hot 600 series. Therefore the Low-Temp Cutoff thermostat has been bypassed with the bottom jumper pin, on the
Electronic Controller, and therefore the Low Temp Cutoff
Status light will always be illuminated.
Low Tank-Level Cutoff
If the light is red and the electric element switch on the interior switch panel is on, then there is a short in the electric
element circuit. This could be due to a bad connection, a bad
switch on the interior switch panel, or an issue with the AC
relay.
The Low Tank-Level Cutoff is controlled by the fluid level
sensor that senses the level of antifreeze in the Boiler Tank,
and will shut the Diesel-Burner and the Electric Heating element OFF, when the light illuminates red.
Heating Zone Status (1-5)
Under normal operating conditions, this light will not be
illuminated because an adequate level of antifreeze and water
heating solution within the Aqua-Hot’s Boiler Tank exists.
NOTE: The Low-Temp Cut-Off light must be illuminated
for the Heating Zones to be activated.
These lights indicate the status of each of the motor home’s
room thermostat and the respective heat exchanger fan (s).
The indicator light will illuminate green when the system is
on and functioning properly, red when on and not functioning, and the light will be off when the system is off.
If a fault condition occurs, this could be due to a wiring issue, a faulty thermostat, or issues with the heat exchanger
fans.
Low Battery Voltage Fault
This indicator light illuminates red when the DC voltage is
below 10.5 Volts for Longer than 5 minutes, and it will be
off when the system has adequate voltage.
When illuminated (red only), four possible issues exist - the
antifreeze and water heating solution level is inadequate and
must be refilled, there is a short in the wiring to the Fluid
Level Sensor, the Fluid Level Sensor is not operating
properly, or Circulation Pump #3 is shorted out.
Heating Status
This indicator light will illuminate (green only) when the
diesel-burner and/or the electric heating element switch on
the interior switch panel is on, and the control thermostat in
the Aqua-Hot Boiler Tank is calling for heat.
If the heater is functioning and the light is not illuminated, or
the heater is not functioning and the light is illuminated,
there is an issue with the wiring or one of the components.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 7: ELECTRONIC CONTROLLER INDICATOR LIGHTS
Engine Preheat Pump
This indicator light shows the status of the Engine Preheat
Pump by illuminating green for on, red for fault, or by turning off when the Engine Preheat Pump is not operating.
The system is functioning properly if the motor home’s interior thermostat is calling for heat, the circulation pump is
active, and the indicator light is green.
The system is functioning correctly when the indicator light
is green while the Engine Preheat Switch on the interior
switch panel is on, the Electric Element and/or Diesel-Burner
switch is on, and the Engine Preheat Pump is operating.
The system is also functioning properly if the circulation
pump and indicator light are off and the thermostat is not
calling for heat.
The system is also functioning correctly when the engine
preheat switch is off and the engine preheat pump is not operating.
If the light illuminates red when the pump should be functioning, then there is either an issue with the wiring or the
Engine Preheat Pump.
If the light is red under any condition, there is either an issue
with the wiring or the circulation pump.
Pump #3
This indicator light shows the status of the circulation pump
that controls the fluid for Heating Zone #5 by illuminating
green for on, red for fault, and by turning off when the system is off.
Pump #1
This indicator light shows the status of the Circulation Pump
that controls the fluid for Heating Zone #1 by illuminating
green for on, red for fault, and by turning off when the system is off.
The system is functioning properly if the motor home’s interior room thermostat is calling for heat, the pump is operating, and the light is green.
The system is functioning properly if the motor home’s interior room thermostat is calling for heat, the pump is operating, and the light is green.
The system is also functioning properly if the pump and light
are off and the interior room thermostat is not calling for
heat.
If the light is red under any condition, then there is either an
issue with the wiring or the circulation pump.
The system is also functioning properly if the pump and light
are off and the interior room thermostat is not calling for
heat.
Diesel-Burner Status
If the light is red under any condition, then there is either an
issue with the wiring or the circulation pump.
This indicator light shows the status of the diesel-burner by
illuminating green when the diesel-burner switch is on, red
for fault, and by turning off when the diesel-burner switch is
turned off.
Pump #2
This indicator light shows the status of the circulation pump
that controls the fluid for Heating Zones #2, #3, and #4 by
illuminating green for on, red for fault, and by turning off
when the system is off.
Pump #2 is also the Stir Pump, and will be activated anytime
the Diesel-Burner is operating, and heating up the antifreeze
solution.
If the diesel-burner switch on the interior switch panel is in
the on position , then the indicator light should be illuminated green.
When the Diesel-Burner switch on the interior switch panel
is in the off position, the indicator light will not be illuminated.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 49 —
SECTION 7: ELECTRONIC CONTROLLER INDICATOR LIGHTS
Diesel-Burner Status (continued)
If the indicator light turns red, there is either a short in the
wiring or the diesel-burner is in need of servicing. When
checking the wiring, be sure to verify that the diesel-burner
controller’s harness connectors are completely locked together. Also verify the Photo Eye Wires have not been pinched.
Reference section 10 of this manual for additional dieselburner information.
Overload Fault
This indicator light shows the status of the DC voltage applied to the electronic controller and the Aqua-Hot. Under
normal operating conditions, this indicator light is off.
This light illuminates red when the Aqua-Hot is shut down
due to excessive DC voltage (over 14.8 Volts) and/or the
electronic controller has overheated. Once the excessive
voltage issue is resolved, the electronic controller will reset
itself.
This light may also illuminate red if one or more of the heater components has a direct short. (i.e. the diesel burner motor, the interior heat exchanger fans, the zone circulation
pump, etc.)
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 50 —
SECTION 8: DIESEL-BURNER
Diesel-Burner Overview
The Aqua-Hot’s diesel-burner is a device that ignites a mixture of diesel fuel and air within a controlled setting to serve
as a heat source. The flame is established in a combustion
chamber within the Aqua-Hot’s boiler tank, and the heat
from the flame is transferred to the antifreeze and water heating solution where it can be used for each system of the Aqua-Hot - domestic hot water, interior heat, and engine preheat.
Figure 27
Figure 28
Fuel Nozzle
Fuel Banjo
Electrode
Adjustment
Gauge
Air Intake
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 51 —
SECTION 8: DIESEL-BURNER
Figure 29
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 52 —
SECTION 8: DIESEL-BURNER
Operational Flow-Chart
Operation sequence once the Aqua-Hot’s Diesel switch is turned
ON
NOTE:
The Diesel switch’s indicator
light will illuminate anytime the
Diesel Burner switch is in the ON
position
The Motor (#2), which turns the
Combustion Air Blower (#5)
and drives the Fuel Pump (#14),
will begin to operate.
NOTE:
If the Aqua-Hot’s coolant temperature is approximately 190°F (+/5°F) or higher, the Motor (#2)
will not operate. Only when the
coolant temperature has dropped
below 160(+/-5)°F, and the VDC/
VAC Control Thermostat is calling for heat, will the Motor (#2)
begin to operate.
Simultaneously, the Ignition Coil
(3) produces a high voltage spark,
which is transferred across the
Ignition Electrodes (8). The incoming air-fuel mixture is then
ignited, creating combustion.
Once the ignited air-fuel mixture
(FLAME) is observed by the
Flame Sensor (#13) the Ignition
Coil (#3) will automatically
switch OFF. The combustion
process now continues to operate
unassisted.
Once the heater switches OFF,
thermostatically or manually, the
Fuel Solenoid Valve (#6) closes,
which interrupts the supply of diesel fuel to the Fuel Nozzle (#9)
The Motor (#2) will continue to run
for approximately three (3) additional minutes. This process is referred to as the Purge-Cycle, which
cools the heater’s internal components and purges the Combustion
Chamber (#11) of any residual
exhaust gases.
NOTE:
The combustion process will continue to operate in this manner
until one of the following occurs:
A.) The VDC/VAC Control
Thermostat, which senses coolant temperature, reaches the preset temperature of approximately
190 (+/-5)° F.
NOTE:
If process “A” occurs, the AquaHot Heating Status Light on the
Electronic Controller will go
OFF.
When the Aqua-Hot’s Diesel Burner is switched OFF by the VDC/
VAC Control Thermostat, the
following process will take place:
1.
The Motor (#2) will shut off
once the three (3) minute
Purge-Cycle has expired.
-THEN2. The Aqua-Hot’s Diesel Burner
will automatically turn back ON
once the coolant reaches the preset
temperature of approximately 160
(+/-5) °F
B.) the Aqua-Hot’s Diesel Burner Switch is turned OFF.
NOTE:
After approximately 10-25 seconds, the Fuel Solenoid Valve
(#6) opens and fuel is sprayed
into the Combustion Chamber
(#11) through the Fuel Nozzle
(#9)
If process “B” occurs, the Diesel
Burner switch’s Indicator
Light, on the Switch Panel will
go OFF along with the Heating
Status and Diesel Burner Status
lights on the Electronic Controller.
Summary:
The Aqua-Hot’s Diesel-Burner is
operational anytime the operator
moves the Diesel Burner Switch to
the ON position. The DieselBurner will then automatically
maintain the coolant temperature in
the Aqua-Hot’s Boiler Tank without additional involvement from the
operator.
Chart 2
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 8: DIESEL-BURNER
Diesel-Burner Operations:
The following sequence illustrates how the Diesel-Burner
operates once it is activated. Also, if diesel-burner malfunctions are experienced, use this sequence of operating events
as a diagnostic tool to determine at what point in the dieselburner’s operation the malfunction is occurring. Use the
“KEY” provided to understand each symbol shown.
Figure 30
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 54 —
SECTION 8: DIESEL-BURNER
Figure 31
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 55 —
SECTION 8: DIESEL-BURNER
Figure 32
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 56 —
SECTION 9: DETACHING
AND
REATTACHING
THE
DIESEL BURNER
Instructions for Detaching the Diesel Burner
WARNING!
Be sure to move the Diesel-Burner switch on the Interior Switch Panel to the OFF position and disconnect the
Diesel-Burner’s power supply before detaching the Diesel-Burner from the Aqua-Hot. Failure to turn off the
Diesel-Burner and disconnect power could result in serious bodily injury.
CAUTION!
Be sure to clamp off the Fuel Supply and Return lines at the ports on top of the Aqua-Hot prior to beginning this
procedure.
Step 1: Turn Off the Diesel Switch
Figure 33
1. Move the Interior Switch Panel’s Diesel-Burner switch to the “OFF” position.
Step 2: Remove the Access Cover
Figure 34a
Figure 34b
1. Remove the Aqua-Hot’s access cover by locating
the screws securing it in place.
2. Unscrew the bolt and screws securing the cover in
place.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 57 —
SECTION 9: DETACHING
AND
REATTACHING
THE
DIESEL BURNER
Step 3: Disconnect the Diesel Burner’s Controller
Figure 35
1. Locate the Diesel-Burner’s Controller and disconnect both plugs.
Step 4: Disconnect the fuel lines from the Aqua-Hot
Figure 36a
Figure 36b
1. Locate where the fuel lines on the diesel burner
connect to the Aqua-Hot Bulkhead fittings.
2. Using an 7/16 wrench, loosen the nuts securing
each fuel line to the Aqua-Hot.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 58 —
SECTION 9: DETACHING
AND
REATTACHING
THE
DIESEL BURNER
Step 5: Remove the Diesel Burner from the Aqua-Hot
Figure 37a
Figure 37b
1. The Diesel-Burner is secured to the Aqua-Hot with two nuts that can be loosened,
and swung out of the way by using a 10mm socket wrench with a 10 inch long
extension.
Figure 37c
2. Carefully pull the Diesel-Burner away from the Aqua-Hot 4 to 5 inches before
rotating the burner, and then remove.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 59 —
SECTION 9: DETACHING
AND
REATTACHING
THE
DIESEL BURNER
Reattaching the Diesel Burner to the Aqua-Hot
CAUTION!
When reattaching the diesel-burner be sure to properly align the diesel-burner before tightening the eye-bolt
nuts. Also, visually inspect all of the rubber grommets on the top and bottom of the diesel-burner’s castaluminum blower casing to ensure they are in place. DO NOT over tighten the eye-bolt nuts. Torque specifications are: approx. 20-40 in. lbs. An improper alignment and/or over tightening of the eye-bolt nuts can
cause damage to the diesel-burner’s cast aluminum blower casing.
Step 1: Reattaching the Diesel Burner to the Aqua-Hot
Figure 38a
1. The Diesel-Burner is secured to the Aqua-Hot with two eye-bolt nuts that can be swung into place,
after the diesel burner has been properly aligned and set in place.
Figure 38b
Figure 38c
2. The eye-bolt nuts can then be tightened by using a 10mm socket wrench with a 10 inch long extension. Use extreme caution when tightening down the eye-bolt nuts, over tightening of the eye-bolt nuts
can cause the aluminum blower casing to crack. (Torque Specifications = Approximately 20-40 in. lbs.)
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 60 —
SECTION 9: DETACHING
AND
REATTACHING
THE
DIESEL BURNER
Step 2: Reattach the fuel lines to the Aqua-Hot.
Figure 39a
Figure 39b
1. Align the fuel lines on the diesel burner with the fittings on the Aqua-Hot, and
using a 7/16 inch wrench, tighten down both the supply and return fuel fittings.
CAUTION!
Be sure to remove the clamps, off of the Fuel Supply and Return lines at the ports on top of the Aqua-Hot prior to
starting the diesel burner, or serious damage will occur to the diesel-burner’s fuel pump.
Step 3: Plug in the diesel-burner’s controller and mount
3. Locate the Diesel-Burner’s Controller and connect both plugs.
Figure 40
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 61 —
SECTION 9: DETACHING
AND
REATTACHING
THE
DIESEL BURNER
Step 4: Reinstall the Access Cover
NOTE: The access cover must be installed prior to operation as a safety switch exists, which will
prevent the Aqua-Hot from operating whenever the access cover is not properly installed.
Figure 41a
1. Reinstall the Aqua-Hot’s access cover .
Figure 41b
2. Securely tighten the bolts and screws securing the
access cover in place.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 62 —
SECTION 10: DIESEL-BURNER COMPONENTS
Figure 42
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 63 —
SECTION 10: DIESEL-BURNER COMPONENTS
If there is no 12 Volts D.C. present on the C-2 pin, continue.
Diesel-Burner Motor:
The motor drives the combustion air blower and the
fuel pump. In order to perform the following procedures, it may be necessary to detach the dieselburner head.
NOTE: The Aqua-hot 600 Series is equipped with a 20A
Fast Blow Fuse, located on the red #20 wire, between the
electronic controller and the diesel burner controller’s BPlug, which is the diesel burner motor power wire.
Inspect the “Fast Blow” fuse on the #20 wire
between the electronic controller and the
Webasto burner controller.
3.
Verify the Electronic Controller is sending power
to the diesel burner motor.
A. Using a volt meter, check for 12 Volt-DC on the
JP4 plug, on the B4 + pin (red wire #3). If no
power is present verify the electronic controller is
receiving power from the batteries.
Component Test:
1.
2.
Locate the diesel-burner controller’s C-Plug and insert
the probes of a DC voltmeter into the C-2 (+) and the C5 (-) locations.
i.
Locate the main power terminals on the
bottom of the electronic controller.
ii.
Using a volt Meter, check for 12 Volt D.C. on the JP 8 terminal. If no voltage is
present, verify that either the jumper is in
place, that connects pins JP5 and JP8 together,
or if there is a power wire hooked up to the
JP8 terminal verify that it is receiving 12 Volt
D.C. from the Motor home’s batteries.
iii.
If the JP8 pin does have 12 Volt D.C. +,
but pin 3, on the JP4 terminal does not have
power, replace the electronic controller.
A. Turn the diesel switch ON and verify both the diesel
burner status light and the heating status lights are
illuminated on the electronic controller. If either
light is not illuminated, follow the trouble shooting
guide for that particular component.
B. Observe the voltage level. If a normal voltage registers on the voltmeter and the motor is not operating,
inspect the C-Plug Harness for loose or damaged
wire connections. If the C-Plug harness and connections are in good condition, but the motor is not
operational the motor must be replaced.
Figure 43
12 Volt D.C. + / - from
coach house batteries.
Fuse for Webasto Blower
Motor
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 64 —
SECTION 10: DIESEL-BURNER COMPONENTS
Diesel-Burner Motor (continued) -
RPM Test:
1.
Disconnect the ignition cables from the ignition
electrodes.
7.
Connect the motor’s wires directly to a 12 volt DC
power supply.
2.
Remove the four ignition coil screws that secure the
ignition coil to the protection cap.
8.
Turn the power supply ON and use a phototachometer to test for a proper RPM reading.
3.
Lift the ignition coil and disconnect its wires from
the C-Plug harness wires prior to removing.
9.
4.
Remove the protection cap from the diesel-burner
so that the motor and clutch halves are exposed.
At approximately 12 volts DC the RPM reading
should be 4500 RPM’s (+/- 300 RPM’s.) If the
motor’s RPM reading is not within the above specs,
the motor must be replaced.
NOTE: It may be necessary to remove the diesel-burner to
remove the bottom two screws securing the protection cap in
place. Follow the direction on detaching and reattaching the
diesel burner in section 9
5.
Place a few wraps of black electrical tape around
the clutch halves and then place a small piece of
reflective tape over the black tape.
6.
Disconnect the motor’s black (+) and brown (-)
wires from the C-plug harnesses black (+) and
brown (-) wires.
NOTE: Test the diesel-burner’s bearings prior to reattaching the diesel-burner head or replacing the motor. Worn
bearings can cause lower than normal RPM readings and
premature motor wear. To properly test for worn bearings,
reference the bearings function test section.
Figure 44
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 65 —
SECTION 10: DIESEL-BURNER COMPONENTS
Motor Replacement Procedure:
Be sure to move the Diesel-Burner switch on the Interior Switch Panel to the OFF position and disconnect the Diesel-Burner’s power supply before detaching the Diesel-Burner from the Aqua-Hot. Failure to turn off the Diesel-Burner and disconnect
power could result in serious bodily injury.
1.
2.
3.
Follow the directions for detaching the diesel burner
in section 9.
Remove the four ignition coil screws that secure the
ignition coil to the protection cap. Lift the ignition
coil to disconnect its wires from the C-plug harness
wires prior to removing. Remove the protection cap
from the diesel-burner so that the motor clutch
halves are exposed.
Remove the three hex head screws that secure the
motor and flange assembly to the blower housing.
Remove the motor and flange assembly along with
the clutch halves. Disconnect the motor’s black (+)
and brown (-) wires from the C-plug harness’ wires.
NOTE: Inspect the clutch halves for cracks and also ensure that the flat portion in each shaft hole is free of wear
and tear. Too much play on the shaft produces a loud clacking noise. If any cracks or wear are detected, the clutch half
must be replaced.
NOTE: Be sure to test the diesel-burner’s bearings prior
to reinstalling the motor. Worn bearings can cause lower
than normal RPM readings and premature motor wear.
6.
Reinstall a clutch half on both the new motor’s shaft
and the combustion air blower shaft. Attach the motor and flange assembly, with the recessed edge of
the motor flange in-line with the wiring access slot of
the blower casing, to the blower housing with the
three hex head screws.
NOTE: Inspect the blower casing’s O-ring for damage or
wear prior to reinstalling the diesel-burner head’s protection
cap. If damage or wear exists, replace the O-ring.
7.
Connect the black (+) and the brown (-) wires of the
new motor to the C-Plug harness’ Black (+) and
brown (-) wires. Feed the C-plug harness’ yellow
and brown wires back through wiring access hole in
the protection cap.
8.
Reinstall the protection cap. Reconnect the ignition
coil wires black (+) to yellow (+) and brown (-) to
brown (-) wires.
9.
Reinstall the ignition coil and secure to the protection
cap with the four ignition coil screws.
10.
Follow the directions for reattaching the diesel
burner in section 9.
11. Test for proper operation
4. Detach the motor from the motor flange by removing
the two Phillips heads screws that fasten the two
parts together.
5. The motor must be mounted to the flange with the
wires and drain hole pointing downward and the
recessed edge of the motor flange pointing upward.
This will ensure a proper protection cap fit.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 66 —
SECTION 10: DIESEL-BURNER COMPONENTS
Figure 45
Motor Replacement Procedure: (continued)
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 10: DIESEL-BURNER COMPONENTS
Flame Sensor:
The flame sensor is a photo resistive device which
supplies the diesel-burner’s controller with a DC
voltage signal when it detects a flame. When the
flame sensor senses the light of the flame, it will
shut the ignition coil off, and send a signal to the
diesel burner controller indicating that everything is
working properly. If the flame sensor does not
sense the flame, it will shut the diesel burner down
in a default after 20 seconds.
NOTE: In order to perform the following procedures it is
necessary to detach and reattach the diesel-burner
head. Be sure to review the detaching/attaching
instructions.
Component Test: Ohms
NOTE: Be sure to calibrate your ohmmeter prior to checking the flame sensor to proper resistance values.
1.
2.
In order to perform the following procedures it is
necessary to detach the diesel-burner. Be sure to
review the detaching/attaching instructions in section 9.
Once the diesel burner has been removed, Locate
and detach the flame sensor’s green and blue wires
from the C-plug harness wires.
3.
Connect the flame sensor’s green and blue wires to
an ohmmeter.
4.
Check resistance by placing a shop rag over the
flame sensor’s glass surface, to simulate a no flame
condition, and then remove the rag and expose to a
light source, to simulate a flame condition.
5.
If the flame sensor is operating properly, the ohmmeter should register high resistance, over 100K Ω
when the glass surface is covered, and less than 200
Ω when exposed to a light source.
6. If these resistance numbers cannot be obtained, verify the flame sensor’s glass surface is clean. If the
flame sensor is clean and the resistance numbers
cannot be obtained, the flame sensor must be replaced.
Flame Sensor Maintenance:
1.
For light dirt, dust, and/or carbon deposits, simply
wipe off the flame sensor with a soft cloth.
2.
Should heavy carbon deposits be present, completely remove the flame sensor from the photo disc and
clean with brake cleaner.
Figure 46
Flame Sensor
Green Wire
Blue Wire
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SECTION 10: DIESEL-BURNER COMPONENTS
Flame Sensor Replacement Procedure:
1.
In order to perform the following procedures it is
necessary to detach diesel-burner head. Be sure to
review the detaching/attaching instructions in section 9.
2.
Remove the screw that fastens the flame sensor to
the photo disc and detach the sensor’s green and
blue wires from the C-plug harness’ green and violet wires, and remove flame sensor.
3.
Slide the tab of the new flame sensor into the provided slot in the photo disc and secure in place with
the screw. Connect the flame sensor’s green wire to
the green C-plug harness wire and the blue wire to
the C-plug harness’ violet wire.
4.
Follow the directions for reattaching the diesel
burner, in section 9 of this manual.
Figure 47
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SECTION 10: DIESEL-BURNER COMPONENTS
Ignition Electrodes
The diesel-burner’s ignition coil produces a high
voltage ignition spark across the ignition electrodes,
which ignites the incoming air/fuel mixture.
Cleaning and Maintenance:
1.
Polish away any carbon deposits that may have
baked onto the metal tips of the ignition electrodes
with a course sponge.
2.
If the ignition electrode’s electrical insulator is
cracked or damaged, the ignition electrode must be
replaced.
NOTE: The electrode adjustment gauge is used to set the
gap between the ignition electrodes. The electrode adjustment gauge is located on the outside surface of the dieselburner head on the left hand side.
Ignition Electrode Adjustment Procedure:
1.
Follow the directions for detaching/reattaching the
diesel burner in section 9 of this manual.
NOTE: Be sure not to over-tighten the retaining clamp
bolt when readjusting the ignition electrodes.
Overtightening the retaining clamp bolt will bend the retaining
clamp and prevent the photo disc from floating freely. Not
allowing the photo disc to float freely will cause poor combustion and result in a smoky exhaust. A bent retaining
clamp can be re-straightened with a punch and hammer.
Lay the clamp’s beveled side down on a solid flat surface
and align the thick end of the punch at dead center. Tap the
punch lightly until the retaining clamp returns to proper
form.
4.
Using a 10 mm socket, tighten the retaining clamp
bolt.
5. Remove the electrode adjustment gauge and reattach to the diesel-burner head.
Replacement Procedure:
1. Using a 10mm socket, loosen and remove the retaining clamp bolt, and the retaining clamp.
2.
Slide the electrode out of the photo disc.
2. Using a 10mm socket, slightly loosen the retaining
clamp bolt.
3.
To remove the electrode, hold onto the orange
electrode boot, and pull firmly on the electrode.
3. Place the electrode adjustment gauge on the nozzle
manifold hex and insert the metal tips of the ignition
electrodes into the appropriate notches of the electrode adjustment gauge.
4. Once the electrode has been removed Inspect inside
the orange electrode boot for the retaining clip,
which holds the electrode in place. If it is missing,
replace the electrode boot.
Figure 48
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SECTION 10: DIESEL-BURNER COMPONENTS
Ignition Electrodes
2.
Replacement Procedure: (continued)
A. Disconnect the steel fuel lines from the diesel
burner.
5. Insert the new electrode into the orange electrode
boot, and snap into place. Pull firmly on the electrode to make sure the retaining clip has secured the
electrode in place.
6.
Slide the electrode into the photo disc.
7.
Install retaining clamp and retaining clamp bolt and
finger tighten.
8.
Hook the diesel burner up to an alternate fuel
source.
3.
Follow steps 1 - 4 to properly adjust the electrodes.
B.
Install a fuel line bypass adapter fitting onto
the diesel burners fuel line
C.
Install rubber fuel lines on both the supply and
return fuel pipes, and install the other end of the
rubber fuel lines into an adequate supply of
diesel fuel. Reference figure 49.
Remove both the ignition cables from the ignition
electrodes, or connect a jumper wire (with alligator
clips) across the metal tips of the electrodes.
Failure to connect a jumper wire across the ignition electrodes, or to remove the ignition cables from the ignition
electrodes will result in a HIGH VOLTAGE shock and/
or a fire. If the ignition cables are removed, be sure to
place a piece of electrical tape on the end of each cable.
Fuel Nozzle:
The fuel nozzle is simply a fuel atomizer. It reduces the
diesel fuel into a fine spray which is mixed with incoming combustion air and is ignited within the combustion
chamber.
NOTE: In order to perform the following procedures it is
necessary to detach and reattach the diesel-burner head. Be
sure to review section 9 for detaching and reattaching instructions.
4.
Remove the B-plug from the diesel-burner head’s
controller.
5.
Turn the diesel switch ON and then plug the B-plug
back into the diesel-burner controller to activate the
diesel-burner. After approx. 20 seconds the fuel
solenoid will “click” and a fine mist of fuel should
appear from the fuel nozzle in a cone shaped spray
pattern.
Fuel Nozzle Component Test:
1. Follow the directions for detaching the diesel burner,
in section 9, of this manual.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
Figure 49
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SECTION 10: DIESEL-BURNER COMPONENTS
2.
Fuel Nozzle:
6.
Remove the B-plug from the diesel-burner controller.
7.
If the cone shaped spray pattern did not appear, fol
low the troubleshooting guides for the following
components and verify they are operating properly:
A. Fuel Solenoid
B. Fuel pump
C. D.C. High Limit thermostats
NOTE: An adjustment of the ignition electrodes may be
necessary after replacing the fuel nozzle. Follow the ignition electrode adjustment procedure found in the ignition
electrode section of this manual.
3.
8. If the components listed above are operating properly, and there is still no fuel coming out of the nozzle,
replace the fuel nozzle.
Fuel Nozzle Cleaning and Maintenance:
The fuel nozzle is a precision calibrated part and
cannot be cleaned or serviced. A replacement
of the fuel nozzle is recommended annually.
Use a 3/4 in. wrench to hold the fuel nozzle stand
hex while loosening the fuel nozzle with a 5/8 in.
wrench and remove.
After replacing the fuel nozzle, reattach the dieselburner head.
Be sure to reattach the diesel-burner head prior to
switching the heater ON. Failure to do so may result in
ignition of the diesel-burner and serious bodily injury.
4.
Turn ON the diesel switch for 5 seconds, then turn
it OFF. This will activate the diesel-burner’s primecycle and flush the fuel system of any potential
contaminants. Perform this procedure twice.
5.
Test for normal operation.
Fuel Nozzle Replacement Procedure:
1.
When replacing the fuel nozzle, be sure to tighten
the nozzle, loosen it a 1/4 turn, and then firmly retighten. This will establish a seated fit and avoid
any leaks.
NOTE: Be sure to use care when handling the new fuel
nozzle. Oils and/or small dust or dirt particles from your
hands may plug the nozzle’s small orifice. A partially
plugged orifice will restrict fuel flow, which will affect the
combustion process of the diesel-burner.
Figure 50
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SECTION 10: DIESEL-BURNER COMPONENTS
stand approximately 1/2”. Remove the fuel solenoid shaft from the nozzle manifold using a 16mm
wrench. Discard the shaft and valve kit, as replacements are provided with the new fuel solenoid assembly.
Fuel Solenoid:
The fuel solenoid allows the flow of diesel fuel to
the diesel-burner’s fuel nozzle.
NOTE: If a long after-smoking condition exists during the
diesel-burner’s purge cycle, the fuel solenoid valve kit may
need to be replaced.
3.
Insert the contents of the new fuel solenoid valve kit
into the new fuel solenoid shaft. Slide the new fuel
solenoid onto the fuel solenoid shaft. Thread the
new fuel solenoid shaft with fuel solenoid to the
fuel nozzle manifold and tighten. Secure the fuel
solenoid in place with the new flat washer and lock
nut.
4.
Connect the C-plug harness’ violet (+) and brown
(-) wires to the fuel solenoid’s (+) and (-) electrical
terminals.
NOTE: In order to perform the following procedures it is
necessary to detach and reattach the diesel-burner head. Be
sure to review the detaching/attaching instructions.
Fuel Solenoid Component Test:
NOTE: If the fuel solenoid is not working troubleshoot the
diesel burner’s hi-limit thermostats. If they are tripped they
will not allow the fuel solenoid to operate.
1.
Locate and detach the C-plug harness’ violet (+)
and Brown (-) wires from the fuel solenoid.
2.
Connect the (-) lead of a 12 volt DC power supply
to the fuel solenoid’s (-) electrical terminal.
3.
Intermittently apply the (+) lead of the power supply to the fuel solenoid’s (+) electrical terminal.
4.
Listen for the fuel solenoid to click (i.e. open and
close).
5.
If the fuel solenoid does not click, it must be replaced.
Figure 51
Fuel Solenoid Replacement Procedure:
1.
Disconnect the C-plug harness’ violet (+) and
brown (-) wires from the fuel solenoid.
2.
Using an 8mm wrench, remove the lock nut and flat
washer from the end of the fuel solenoid shaft and
then pull the fuel solenoid away from the nozzle
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 10: DIESEL-BURNER COMPONENTS
Fuel Pump:
The fuel pump draws diesel fuel from the vehicle’s
fuel tank and creates a preset pressure of 145 PSI,
which is required for proper fuel atomization. Reference the illustration below for a basic overview
and understanding of how the fuel pump functions.
7. If fuel does flow through the fuel pump when ran
off an external source inspect the following in the
motor home:
A. Check the motor home fuel tank for fuel. If the
fuel level is below 1/4 the Aqua-Hot diesel
burner will not operate.
Fuel Pump Testing Procedure:
Do not remove the diesel burner at this time. Failure to
do so may result in serious bodily injury.
1.
Clamp off and remove the fuel return and fuel supply lines coming into the Aqua-Hot unit.
2.
Attach a short piece of fuel line to both the inlet and
outlet fuel ports
3.
Submerse the opposite end of the temporary fuel
supply line in a container of diesel fuel.
4.
Place the opposite end of the temporary fuel return
line in an empty container.
5.
Turn the diesel switch ON to activate the dieselburner, and wait ten seconds.
6.
If fuel does not flow out of the return line into the
empty container, the fuel pump must be replaced.
NOTE: Prior to replacing the fuel pump, be sure to inspect the screen filter in the supply inlet of the fuel pump for
dirt particles. Clean and/or replace if necessary. A plugged
screen filter will restrict fuel from entering the fuel pump.
Also, be sure to inspect for cracked or loose fittings on the
supply line. A cracked or loose fitting on the supply line
will allow air to enter into the fuel system.
B.
Inspect the supply fuel line for kinks which
would prohibit fuel flow.
C.
Inspect the supply fuel line for cuts, which
would cause the diesel burner to suck air.
D. Inspect the fuel filter, to make sure all fittings
are tight, including hose clamps. Also, make
sure the fuel filter is tight.
E.
Inspect the Aqua-Hot for loose or cracked
fittings.
F. Inspect the supply fuel system for loose hose
clamps throughout
G. Inspect the fuel pick-up tube in the tank., for
loose connection and pin holes in the pick-up
tube
Fuel Pump Cleaning and Maintenance:
1.
Check all fuel connections for tightness.
2.
Check the screen filter located in the fuel supply
inlet of the fuel pump for dirt particles. Clean and/
or replace if necessary.
3.
To adjust the fuel pressure refer to Appendix C:
Fuel pressure check and adjustment..
Figure 52
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SECTION 10: DIESEL-BURNER COMPONENTS
Fuel Pump Replacement Procedure:
NOTE: To perform the following procedure it will be necessary to remove the diesel burner. Follow the section on
detaching and reattaching the diesel burner, section 9 of this
manual.
1.
2.
3.
4.
5.
6.
Locate and disconnect the C-Plug harness wires that
connect to the flame sensor and the fuel solenoid.
Also, disconnect the ignition cables from the ignition electrodes.
Remove the retaining clip that secures the photo
disc in place. Gently lift the photo disc so that it
releases from the nozzle stand and the ignition electrodes.
Loosen the supply and return banjo bolts to remove
the fuel supply and return pipes from the fuel pump.
Also, disconnect the high pressure fuel pipe from
both the fuel pump and the nozzle stand. Discard
the high pressure fuel pipe, gasket rings, and banjo
bolts , as replacements are provided in the new fuel
pump kit.
Remove the four nozzle stand plate screws that secure the nozzle stand plate in place. Remove the
nozzle stand plate by pulling on the nozzle stand
until the plate releases from the cast-aluminum
blower casing.
Remove the two pump mounting screws that secure
the fuel pump in place. Turn the nozzle stand plate
over and remove the snap ring from the fuel pump
shaft, using snap ring pliers. Remove the nylon
drive gear and then the fuel pump.
Attach the new fuel pump to the nozzle stand plate
with the two pump mounting screws. Turn the nozzle stand plate over to install the nylon drive gear on
the fuel pump’s shaft and secure in place with the
snap ring. Dab the teeth of the nylon drive gear
with white lithium grease (Isoflex LDS-18 is recommended.)
Do not adjust the fuel pressure regulator of the
NOTE:
new fuel pump, as it has been factory preset.
Inspect the nylon drive gear’s cavity inside the cast aluminum blower casting for fuel stains. If fuel stains are present,
a replacement of the bearings and/or the entire blower casing may be necessary. Leaking fuel could cause bearing
seizure, resulting in potential damage to the internal bore/
bearing of the blower casing.
7.
Fit the nozzle stand plate inside the cast-aluminum
blower casing and secure in place with the four nozzle stand plate screws. Install the grommets on the
fuel return and supply banjo pipes and secure the
pipes to the fuel pump with the new banjo bolts and
gasket rings.
NOTE: Failure to use the new gasket rings or the correct
order placement could result in a fuel leak.
8.
Reconnect the C-plug harness’ violet (+) and brown
(-) wires to the fuel solenoid’s (+) and (-) electrical
terminals.
9.
Insert both the ignition cables into the rubber grommet and slide into the appropriate notch on the
blower casing.
10. Reconnect the ignition cables to the ignition electrodes.
11. Reinstall the photo disc and secure it in place with
the retaining clip.
12. Reconnect the flame sensor’s green wire to the
green C-plug harness and the blue wire to the
C-plug harness’ violet wire. Install rubber
grommet around the harness wires, and set into
place.
NOTE: Check the ignition electrodes for proper
adjustment prior to reattaching the diesel burner.
13. Follow the directions for reattaching
burner in section 9 of this manual.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
the diesel
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SECTION 10: DIESEL-BURNER COMPONENTS
Fuel Pump: (continued)
Figure 53
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SECTION 10: DIESEL-BURNER COMPONENTS
Bearings:
5.
Remove the three hex head screws that secure the
motor and motor flange to the blower housing. Re
move the motor and flange assembly along with the
clutch halves. Disconnect the motor’s black (+) and
brown (-) wires from the C-plug harness’ wires.
6.
Remove the four blower housing screws that secure
the blower housing to the blower casing. Remove
the blower housing so that the combustion air
blower is exposed.
7.
Spin the combustion air blower by hand. Placing
one of the clutch halves to the end of the shaft, assists with the spinning of the bearings.
8.
If the combustion air blower rotates smoothly without any friction or noise, the bearings are in proper
working condition. If the combustion air blower
does not rotate smoothly and/or produces noise, the
bearings are worn and must be replaced.
The bearings support the combustion air blower’s
shaft and allows the blower to turn smoothly.
NOTE: In order to perform the following procedures it is
necessary to detach and reattach the diesel-burner head. Be
sure to review section 9 for detaching and reattaching the
diesel burner instructions
Bearing Test:
1.
2.
In order to perform the following procedure it is
necessary to detach and reattach the diesel-burner
head. Be sure to review the detaching and reattaching section for detaching and reattaching instructions.
Locate and disconnect the C-plug harness wires that
connect to the flame sensor and fuel solenoid. Also,
disconnect the ignition cables from the ignition
electrodes.
Replacement:
3.
Remove the four nozzle stand plate screws that secure the nozzle stand plate in place. Remove the
nozzle stand plate by pulling on the nozzle stand
until the plate releases from the cast-aluminum
blower casing.
1.
In order to perform the following procedure it is
necessary to detach and reattach the diesel-burner
head. Be sure to review the detaching and reattaching section for detaching and reattaching instructions.
4.
Remove the four ignition coil screws that secure the
ignition coil to the protection cap. Lift the ignition
coil and disconnect its black (+) and brown (-) wires
from the C-plug harness wires, prior to removing.
Remove the protection cap from the diesel-burner
so that the motor and clutch halves are exposed.
2.
Locate and disconnect the C-plug harness wires that
connect to the flame sensor and fuel solenoid. Also,
disconnect the ignition cables from the ignition
electrodes.
Figure 54
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 10: DIESEL-BURNER COMPONENTS
3.
Remove the four nozzle stand plate screws that secure the nozzle stand plate in place. Remove the
nozzle stand plate by pulling on the nozzle stand
until the plate releases from the cast-aluminum
blower casing.
NOTE: It is recommended to mark the internal components
of the diesel burner prior to disassembling of the burner.
Make a mark between the motor flange and the blower
housing, and also between the blower housing and the blower casing. If the burner is assembled improperly the protection cap will not go on.
4.
5.
Remove the four ignition coil screws that secure the
ignition coil to the protection cap. Lift the ignition
coil and disconnect its black (+) and brown (-) wires
from the C-plug harness wires, prior to removing.
Remove the protection cap from the diesel-burner
so that the motor and clutch halves are exposed.
Remove the three hex head screws that secure the
motor and motor flange to the blower housing. Remove the motor and flange assembly along with the
clutch halves. Disconnect the motor’s black (+) and
brown (-) wires from the C-plug harness’ wires.
6.
Remove the four blower housing screws that secure
the blower housing to the blower casing. Remove
the blower housing so that the combustion air blower is exposed.
7.
Hold side-B of the blower casing and loosen the
retaining nut located in side-A of the blower casing.
Remove the retaining nut, steel drive gear and thick
flat washer from the combustion air blower’s shaft.
Lightly tap the threaded end of the shaft so that the
combustion air blower can be easily removed from
the blower casing.
NOTE: Be sure to inspect the blower casing’s bore/bearing
cavity for signs of damage due to potentially seized bearings. If damage is present, the blower casing must be replaced.
9.
Install a new snap ring into side-A of the blower
casing. Once the snap ring is in place, insert the
remaining contents of the new bearing kit into sideB of the blower casing, starting with the wave
washer. Secure the bearing kit assembly in place
with the remaining snap ring.
10. Inspect the combustion air blower for warping and/
or damage. If warping or damage is visible, the
combustion air blower must be replaced.
11. Reference Figure 55 for exact placement of the
three washers that slide over the threaded end of the
combustion air blower’s shaft prior to installation.
Failure to follow the correct order and direction of
the dished surfaces on the washers will result in a
restricted rotation of the combustion air blower.
12. Slide the combustion air blower’s shaft (with the
three washers) up through the bearing kit assembly
until the threaded portion appears on side-A of the
blower casing. Place the new thick flat washer and
steel drive gear on the threaded end of the combustion air blower’s shaft. Thread the new retaining
nut on the combustion air blower’s shaft until it is
finger tight (DO NOT TIGHTEN.)
Figure 55
NOTE: Be sure to observe the placement of the three
washers of the bearing kit. To ensure proper tension, the
same order and direction of the dished surfaces of the washers must be followed when reassembling.
8.
With a pair of snap-ring pliers, remove the snap
rings from both side-A and side-B of the blower
casing. Push all the contents of the bearing kit out
of the blower casing’s bore/bearing cavity. Discard
the retaining nut, steel drive gear, snap rings, bearings, spacer tube, and washers, as replacements are
provided in the new bearing kit.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 10: DIESEL-BURNER COMPONENTS
12. Place a feeler gauge between the combustion air
blower and the flat surface of the blower casing.
Slowly tighten (or loosen) the retaining nut, holding
the combustion air blower, until a .018-.020 gap is
achieved. Remove feeler gauge.
13. Spin the combustion air blower to ensure a
friction free rotation.
NOTE: If the combustion air blower is rubbing, loosen the
retaining nut slightly and lightly tap on the combustion air
blower’s shaft (opposite side) then readjust the gap.
14. Reattach the blower housing to the blower casing
using the four blower housing screws. Reinstall the
clutch half on both the motor’s shaft and the combustion air blower’s shaft. Attach the motor and
flange assembly, with the recessed edge of the motor flange in-line with the wiring access slot of the
blower casing, to the blower housing with the three
hex head screws. Reconnect the black (+) and
brown (-) wires of the motor to the C-plug harness’
black (+) and brown (-) wires. Feed the C-plug
harness’ yellow and brown wires back through the
wiring access hole in the protection cap.
NOTE: Inspect the clutch halves’ for cracks and also ensure that the flat portion in each shaft hole is free of wear
and tear. Too much play on the shaft produces a loud clacking noise. If any cracks or wear are detected, the clutch half
must be replaced.
15. Reinstall the protection cap. Reconnect the black
(+) and brown (-) wires of the ignition coil to the Cplug harness’ yellow (+) and brown (-) wires. Reinstall the ignition coil and secure to the protection
cap with the four ignition coil screws. Reconnect
the ignition cables to the ignition electrodes.
16. Fit the nozzle stand plate inside the cast aluminum
blower casing and secure in place with the four nozzle stand plate screws. Reattach the fuel supply and
return lines to the diesel-burner head.
17. Reconnect the blue (+) and brown (-) wires to the
fuel solenoid’s (+) and (-) electrical terminals. Also, reconnect the flame sensor’s green wire to the
green C-plug harness wire and the blue wire to the
C-plug harness’ violet wire.
18. Follow the instructions for reattaching the diesel
burner, in the detaching/reattaching section in this
manual.
Figure 56
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 10: DIESEL-BURNER COMPONENTS
Ignition Coil:
The ignition coil produces a high voltage ignition
spark (approx. 8000 volts), which is released across
the metal tips of the ignition electrodes during the
initial diesel-burner start-up.
Use extreme care when testing the ignition coil, as a High
Voltage Shock may result.
NOTE: In order to perform the following procedures it is
necessary to detach and reattach the diesel-burner head. Be
sure to review the section for detaching and reattaching the
diesel burner..
Component Test:
1.
Remove the four ignition coil screws that secure the
ignition coil in place.
2.
Disconnect the ignition coil’s black (+) and brown
(-) wires from the C-plug harness’ yellow (+) and
brown (-) wires.
3.
Connect the ignition coil wires directly to a 12 volt
DC power supply (i.e. black (+) wire to (+) lead and
brown (-) wire to (-) lead).
4.
Turn the power supply ON and watch for a spark to
appear across the metal tips of the ignition electrodes. If a spark does not appear, the ignition coil
must be replaced.
NOTE: Some ignition coils are intermittent and will need
to be tested numerously
Before replacing the ignition coil:
1. Verify the ignition electrodes are not cracked or broken.
2. Verify that the ignition electrodes are adjusted properly.
3. Ensure the electrode boots are securely holding the
electrodes in place.
4. Ensure the electrode boots are not broken inside the ignition coil wires.
Figure 57
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 10: DIESEL-BURNER COMPONENTS
Ignition Coil:
NOTE: In order to perform the following procedures it is
necessary to detach and reattach the diesel-burner head. Be
sure to review the section for detaching and reattaching the
diesel burner..
3.
Connect the new ignition coil cables, to the ignition
electrodes.
4.
Connect the new ignition coil’s black (+) and brown
(-) wires to the C-plug harness’ yellow (+) and
brown (-) wires. Attach the ignition coil to the
protection cap with the four ignition coil screws,
then reconnect the ignition cables to the ignition
electrodes.
Replacement Procedure:
1.
2.
Disconnect the ignition cables from the ignition
electrodes. Remove the four ignition coil screws
that secure the ignition coil to the protection cap.
Lift the ignition coil and disconnect its wires from
the C-plug harness wires, prior to removing.
Disconnect the ignition cables, on the defective
ignition coil, from the ignition electrodes.
NOTE: If the new ignition coil does not function, check
wire connections and ensure they are properly connected.
5.
Follow the instructions for reattaching the diesel
burner and test for proper operation.
Figure 58
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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SECTION 10: DIESEL-BURNER COMPONENTS
Diesel-Burner Controller:
The diesel-burner controller operates all the components of the diesel-burner head and safely shuts the
heater OFF in the event of an overheat, flameout,
and low voltage condition. It also receives dieselburner operation status signals from the flame sensor, VDC control thermostat, and VDC high-limit
thermostat.
Component Test:
VDC/VAC Control Thermostat Circuit Test:
Locate the diesel-burner controller’s B-plug and Cplug. Insert the probes of a DC voltmeter into the C
-1 (+) and B-2 (-) locations and turn the diesel
switch ON. If a voltage reading does not register on
the voltmeter, the diesel-burner controller must be
replaced. If voltage is present, proceed to the next
circuit test.
VDC High-Limit Thermostat Circuit Test:
The following conditions must exist prior to performing the diesel-burner controller circuit tests on
the following page. If one of the conditions below
does not exist, please contact our technical support
department at 1-800-685-4298 for additional assistance.
Condition #1
A battery voltage level between 11.5 to 14.0 volts
DC must be present at the diesel-burner controller
during all testing. It may be necessary to perform a
voltage check to ensure that this condition exists.
To perform the voltage check, locate the dieselburner controller’s B-plug, and insert the probes of
a DC voltmeter into the B-4 (+) and B-2 (-) locations.
Condition #2
A voltage level of between 11.5 to 14.0 volts must
be present at the diesel ON/OFF switch circuit of
the diesel-burner controller during all testing. It
may be necessary to perform a voltage check to
ensure that this condition exists. To perform the
voltage check, locate the diesel-burner controller’s
B-plug, and insert the probes of a DC voltmeter into
the B-1 (+) and B-2 (-) locations. Turn the diesel
switch ON and observe the voltage level.
Ground Circuit Test:
Locate the diesel-burner controller’s B-plug and Cplug. Insert the probes of a DC voltmeter into the B
-4 (+) and C-5 (-) locations and turn the diesel
switch ON. If a voltage reading does not register on
the voltmeter, the diesel-burner controller must be
replaced. If voltage is present, proceed to the next
circuit test.
Locate the diesel-burner controller’s B-plug and Cplug. Insert the probes of a DC voltmeter into the C
-4 (+) and B-2 (-) locations and turn the diesel
switch ON. If a voltage reading does not register on
the voltmeter, the diesel-burner controller must be
replaced. If voltage is present, proceed to the next
circuit test.
Motor Circuit Test:
Locate the diesel-burner controller’s B-plug and Cplug. Use a jumper wire to make a connection from
the C-1 location to the C-7 location. Turn the diesel
switch ON and insert the probes of a DC voltmeter
into the C-2 (+) and C-5 (-) locations. If no voltage
reading registers on the voltmeter, the diesel-burner
controller must be replaced. If voltage is present,
proceed to the next circuit test.
Be sure to remove the jumper wire that was used to make the
connection from the C-1 location to the C-7 location. A failure to do so will result in an overheating condition during
normal operation.
Ignition Coil Circuit Test:
Turn the diesel switch OFF and locate the dieselburner controller’s C-plug. Also, locate the VDC
high-limit thermostat and disconnect it’s 2-way
male plug from the (white plastic) 6-way female
connector. Insert the probes of a DC voltmeter into
the C-8 (+) and C-5 (-) locations and turn the diesel
switch ON. If a voltage reading does not register on
the voltmeter 18-25 seconds after the initial start-up
the diesel-burner controller must be replaced.
NOTE: Be sure to reconnect the VDC high-limit thermostat’s 2-way male plug to the 6-way female plug. The diesel
-burner will not ignite during normal operation if the VDC
high-limit thermostat is left disconnected.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 82 —
SECTION 10: DIESEL-BURNER COMPONENTS
Be sure to remove the jumper wire that was used to make the
connection from the C-1 location to the C-7 location. Failure
to do so will result in an overheating condition during normal
operation.
Figure 59
Replacement Procedure:
1. Remove both the B-plug and the C-plug from the
diesel-burner controller. Gently pry away each side
of the diesel-burner controller bracket from the diesel-burner controller’s locking posts with a flat-head
screw driver. Once the locking posts have been
released, pull on the diesel-burner controller to remove it from the diesel-burner head.
2. Slide the new diesel-burner controller into the diesel
-burner controller bracket. Push down on the diesel
-burner controller until the locking posts snap into
the bracket slots.
3. Reconnect the B-plug and the C-plug.
NOTE: Be sure to install the diesel-burner controller
with it’s C-plug and B-plug ports facing downward. Failure
to do so, will result in moisture collecting in the ports and
potential damage to the diesel-burner controller’s internal
circuitry.
Figure 60
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 83 —
SECTION 11:
TROUBLE SHOOTING
1. Black Smoke
1.
Is the heater experiencing a low voltage condition.
8.
A. Fire up the generator or plug the coach into
shore power.
2.
A. Remove the Combustion Chamber and inspect for
signs of damage. Inspect the aluminum for signs of
warping, or melted aluminum.
Is the Exhaust Pipe Damaged or Restricted?
9.
A. Inspect the exhaust pipe for damage, or excessive
bends.
NOTE: The Access cover will need to be removed to check
the following.
3.
Is the Air Intake closed off?
A. The Air Intake is located on the bottom of the diesel
burner, and should be adjusted to the halfway point.
B. There is a rubber air intake sleeve on the air intake, and
If it is collapsed it will need to be replaced.
4.
Is the Combustion Chamber warped or melted?
Is the Nozzle bad?
10. Is the Fuel Pressure set at 145 PSI?
A. Check the fuel pressure with the fuel pressure gauge.
NOTE: The Diesel Burner will need to be tore down to check
the following.
11. What are the RPM’s of the Combustion Blower Motor?
A. The RPM’s should be 4500 rpm at 12 VDC.
B. If the motor is running slow inspect the bearings before
replacing the blower motor.
Is the Protection Cap damaged or cracked?
12. Are the bearings faulty?
A. Inspect the protection cap for cracks or holes.
5.
Are the Right and Left Grommets Worn out?
A. Are they hard and brittle?
B. Has the rubber been cut out, around the wires?
C. Are they positioned correctly.
6.
A. The bearings should spin freely, and sound smooth.
B. Bearings that are bad will slow the motor down.
13. Is the Impeller fan gapped properly?
A. The impeller fan should be gapped between .018 - .020
thousands
Is the burner properly positioned and secured properly.
A. Inspect the burner to ensure it is aligned properly.
B. Tighten the Eye Bolts securing the burner in place.
Caution
NOTE: Anything that throws off the air fuel mixture in the
combustion chamber is a possible cause of black smoke
Do not over tighten the eye bolts, or damage to the diesel
burner may result. Tighten the Eye Bolts to 20-40 inch
pounds.
NOTE: The Diesel Burner must be removed to check the
following.
7.
Is the Photo Disc bent or tight.
A. The photo disc must be free floating. If it is bound up,
it will not seat against the combustion chamber.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 84 —
SECTION 11:
TROUBLE SHOOTING
2. Blue/White Smoke
1. If the heater is smoking blue/white smoke
during the start up or shut down cycle:
A. Is the Fuel Solenoid functioning properly
i. Test the fuel solenoid and make sure it
engages as soon as power is put to it. Any
delay in the fuel solenoid may cause blue/
white smoke.
ii. Remove the fuel solenoid and inspect the
plunger for any damage or debris that may
interfere with the fuel shutting down.
B. Is the Nozzle Tower Damaged?
i. Inspect the area where the nozzle screws
in for cracks in the brass.
ii Remove the fuel solenoid and inspect the
plunger seat for poorly machined brass.
C. Is the Diesel Burner short cycling (turning
off and on more frequently than normal).
i. Test the control thermostat to ensure it is
operating within the proper range.
ii. Ensure someone has not turned the heater
off and on several times.
NOTE: Webasto says it is normal for there to be a short puff
of smoke after the flame has shut down, due to the nozzle tower emptying the fuel out.
2. If the heater is smoking blue/white smoke during
the Burn Cycle:
A. Are the electrodes adjusted properly?
i. Use the gauge on the side of the diesel burner
to properly adjust the ignition electrodes.
B. Are the air bubbles in the fuel system?
i. If the fuel pump is sucking air at any point,
on the supply fuel system, the heater will
continuously puff out blue/white smoke.
C. Is the Fuel Nozzle Bad?
D. Is the Fuel Pressure Adjusted properly?
i. The fuel pressure should be 145psi
E. Is the Fuel Pump Leaking?
i. If the fuel pump is leaking it will need to be
replaced.
F. Is the Ignition Coil igniting every time?
i. An intermittent Ignition Coil will allow fuel
to spray into the combustion chamber,
without igniting it every time.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 85 —
SECTION 11:
3. Lack of Interior Heat
A. Is the Diesel Burner /Electric Heating Element
working properly?
B. Is the Heater up to operating temperature?
C. Is the Interior Room Thermostat Calling for heat?
D. Is the Zone Circulation Pump operating?
E. Are the Heat Exchanger fans operating?
4. Lack of Domestic Hot Water
1. Things to keep in mind when trouble shooting a
heater for a lack of hot water.
A. The Diesel Burner must be on for continuous
hot water
NOTE: The Electric Element is designed to be used
during low heat demand situations, and will not supply
continuous hot water
B. The Heater is only rated for a water flow of
1.5GPM.
C. The heater is only rated for a 55°F Temperature
rise on the cold water coming in.
2. Check the following if there is a lack of domestic
hot water:
A. Is the heater bypassed?
B. Has the Outside water faucet been left on?
i. If both the cold and hot valves are left in the
on position, the outside water faucet acts like
a secondary mixer valve, and the remaining
hot water faucets will only produce warm
water.
TROUBLE SHOOTING
F. If the Heat Exchanger Fans, and the Zone
Circulation Pumps are operating check for the
following:
i. Stuck Check Valve
ii. Inspect for a Kinked plumbing line.
iii. Is there a Lack of antifreeze in the boiler
tank.
G. Is the Low Temperature Cutoff Thermostat
light, on the electronic controller, out?
H. Is the Electronic Control Board working
properly?
C. Has the Internal Washing Machine Valve
gone bad?
i. If both the internal washing machine valve
has gone bad it acts like a secondary
mixer valve, and the remaining hot water
faucets will only produce warm water.
D. What is the Antifreeze concentration?
i. The proper antifreeze concentration
should be between 30%-50% antifreeze.
If the concentration is over a 50%
antifreeze concentration the antifreeze
does not transfer the heat properly and t
here will be a lack of domestic hot water.
E. What is the operating range of the control
thermostat?
i. 155 ° F to 185 °F
F. What is the Water Flow (GPM)
i. The water flow must be 1.5GPM or less
ii. Test the water flow where the customer is
complaining about lack of hot water
(i.e. shower, sink, etc.)
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 86 —
3. Lack of Domestic Hot Water (Continued)
G. Is the Mixer Valve functioning properly.
i. The mixer valve’s adjustment knob
should turn freely. If the adjustment knob
does not have free movement, the mixer
valve must be replaced.
4. Antifreeze Leak
NOTE: To find an antifreeze leak, the system must
be Hot (up to operating temperature) or pressurized
to 15 PSI.
Inspect the following components on the Aqua-Hot
Heating System for Leaks :
1. On the Front-Side of Aqua-Hot:
A. Fluid Level Sensor
NOTE: It might be necessary to cut away some of the
insulation around the tank ports to locate the leak.
B. Control Thermostat
NOTE: It might be necessary to cut away some of the
insulation around the tank ports to locate the leak.
C. Drain Valve and Hose going to the drain
valve
F. Domestic Water/Engine Preheat copper
pipe
i. The copper pipes come out of the boiler
tank and are possible leak points
G. Burn Chamber Leak
i. If Antifreeze is running out of the tip of
the exhaust pipe remove the burner, and
combustion chamber and inspect inside
the burn chamber for leaks.
2. On the Top-Side of Aqua-Hot:
A. Expansion Tank Connection
i. Cracked expansion tank tubing
ii. Loose air release valve
iii. Brass hose barb fitting defective or loose
B. Supply/Return Ports
i. Defective fitting
ii. Leaking fitting
D. Electric element
E. Circulation Pump
i. Hoses
ii. Tank ports
NOTE: It might be necessary to cut away some of the
insulation around the tank ports to locate the leak.
iii. Pump
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 87 —
APPENDIX A: WIRING DIAGRAM FOR AHE-600-D03 MANUFACTURED
BEFORE
JANUARY 2011
Figure A1
AHE-600-D03
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 88 —
APPENDIX A: WIRING DIAGRAM FOR AHE-600-D03 MANUFACTURED AFTER JANUARY 2011
Figure A2
AHE-600-D03
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 89 —
APPENDIX A: WIRING DIAGRAM FOR AHE-675-D03 MANUFACTURED BEFORE JANUARY 2011
Figure A3
AHE-675-D03
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 90 —
APPENDIX A: WIRING DIAGRAM FOR AHE-675-D03 MANUFACTURED
AFTER
JANUARY 2011
Figure A4
AHE-675-D03
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 91 —
APPENDIX B: WIRE GAUGE INFORMATION
Because all Aqua-Hot heating systems are designed to operate only when there is an adequate supply of DC (Direct Current) voltage,
it is imperative that the proper wire gauge be determined and used for the DC power supply and ground wires. This bulletin addresses how to determine the DC amperage draw of the heating system, including heat exchangers, then, how to determine the proper wire
gauge based upon those findings for a specific application.
Figure B1
Determining the DC Amperage Draw of the Heating System:
1. Review the chart above for the amperage draw of each Aqua-Hot heater (excludes heat exchangers).
2. Determine the number of heat exchangers installed with the Aqua-Hot Heating System.
NOTE:
Each heating zone “FAN” circuit can supply up to 2.0 amps of direct current.
3. Consult the heat exchanger’s manufacturer for amp-draw information.
NOTE:
Each Aqua-Hot Cozy heat exchanger draws .23 amps of direct current.
Each Aqua-Hot Whisper heat exchanger draws .38 amps of direct current.
4. Determine the total amperage draw for all heat exchangers installed.
For example, if six Aqua-Hot Cozy heat exchangers have been installed, multiply the amperage draw of
each heat exchanger (.23 amps) by the number of heat exchangers (6). The total amperage draw in this
scenario would be 1.38 amps.
5. Add the total heat exchanger amperage draw to the amperage of the installed Aqua-Hot.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 92 —
APPENDIX B: WIRE GAUGE INFORMATION
For example, an Aqua-Hot 600-D with six Aqua-Hot Cozy heat exchangers has a total amperage draw of
23.38 amps .
Determining the Proper Wire Gauge:
1. Measure the total length of the wire required for the distance between the vehicle’s battery and the electronic controller for Aqua-Hot models 450-DE, 450-DM, 525-D, 600-D, and 675-D and the heater itself for
the Aqua-Hot 375-D model.
2. Using the determined length and total amperage draw, consult the wire gauge chart included in this bulletin. Round up to the closest amp draw listed on the left, then round up to the closest length at the top of the
chart.
For example, an Aqua-Hot 600-D heater with six Aqua-Hot Cozy heat exchangers with the electronic controller placed 15 feet from the vehicle’s battery would require an 8-gauge wire.
Wire Gauge Chart:
Figure B2
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 93 —
APPENDIX C: FUEL PRESSURE CHECK
AND
ADJUSTMENT
Instructions for Checking Fuel Pressure
NOTE:
A fuel pressure gauge is used to properly check the fuel pump’s pressure setting. The fuel pump is preset to 145 PSI. Perform the
following procedures to check for a proper fuel pressure setting.
NOTE: In order to perform the following procedure it is necessary to detach and
reattach the diesel-burner head. Be sure to review the detaching/attaching instructions.
Step 1: Remove the diesel-burner
Figure C1
1. Refer to the section on detaching/reattaching the diesel burner, to detach the diesel burner.
Step 2: Install fuel line bypass fittings onto the diesel burner.
Figure C2
1/4” Fuel
Tube unions
1. Locate the 1/4 “ fuel tube unions on the bottom side of diesel burner.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 94 —
APPENDIX C: FUEL PRESSURE CHECK
AND
ADJUSTMENT
Instructions for Checking Fuel Pressure
Step 2: Install fuel line bypass fittings onto the diesel burner. (continued)
Figure C3
2. Using a 13mm and a 9/16” wrench remove Steel Fuel lines from the diesel Burner
Figure C4
3. Install the fuel bypass fittings onto the diesel Burner
NOTE: It may be possible to install rubber fuel lines over the Steel fuel pipes, instead of disconnecting them
and using a fuel bypass fitting.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 95 —
APPENDIX C: FUEL PRESSURE CHECK
AND
ADJUSTMENT
Instructions for Checking Fuel Pressure
Step 3: Installing the fuel pressure gauge
Figure C5
1. Using a 5/8” and a 3/4” wrench remove the fuel nozzle.
Figure C6
2. Using a 5/8” and a 3/4” wrench install the fuel pressure gauge.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 96 —
APPENDIX C: FUEL PRESSURE CHECK
AND
ADJUSTMENT
Instructions for Checking Fuel Pressure
Step 3: Running the burner off of an external fuel source
Figure C7
1. Using an external fuel source and rubber fuel line, hook the Webasto burner supply and return fuel
lines up to run off of the external fuel source.
WARNING!
A spark will appear across the ignition electrodes for a brief moment after the diesel burner has been activated.
DO NOT attempt to make any fuel pressure adjustments until the spark has disappeared. Failure to do so may
result in serious bodily injury. In some installations it may be necessary to shine a light on the flame sensor to
simulate a flame condition to shot of the ignition coil.
Figure C7
2. Turn the diesel burner switch to the on position. A pressure will register on the fuel pressure gauge
once the fuel solenoid opens (after approx. 10-20 seconds.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 97 —
APPENDIX C: FUEL PRESSURE CHECK
AND
ADJUSTMENT
Instructions for Adjusting Fuel Pressure
Step 1: Follow the directions for Checking the Fuel Pressure in this section.
Figure C8
1. Using an external fuel source and rubber fuel line, hook the Webasto burner supply and return fuel
lines up to run off of the external fuel source.
WARNING!
A spark will appear across the ignition electrodes for a brief moment after the diesel burner has been activated.
DO NOT attempt to make any fuel pressure adjustments until the spark has disappeared. Failure to do so may
result in serious bodily injury. In some installations it may be necessary to shine a light on the flame sensor to
simulate a flame condition to shot of the ignition coil.
Figure C9
2. Turn the diesel burner switch to the on position. A pressure will register on the fuel pressure gauge
once the fuel solenoid opens (after approx. 10-20 seconds.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 98 —
APPENDIX C: FUEL PRESSURE CHECK
AND
ADJUSTMENT
Instructions for Adjusting Fuel Pressure
Step 2: Adjust the Fuel pressure to 145 PSI.
Figure C10
1. Once the fuel solenoid has been activated, and the fuel pressure gauge is registering a pressure, the
fuel pressure can be adjusted. To increase the fuel pressure turn the pressure adjustment screw clockwise, and to reduce the fuel pressure, turn the pressure adjustment screw counter clockwise.
NOTE: If the fuel pressure cannot be adjusted refer to the fuel pump section in section 10 of this
manual for troubleshooting tips.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 99 —
APPENDIX D: EXTREME COLD WEATHER OPERATION
Diesel-Burner
When storing the Motorhome: Not winterizing the AquaHot when freezing temperatures are present will result in
serious damage to the Aqua-Hot’s Domestic Water Heating
System. Also, be sure to use an FDA approved, “GRAS”
rated antifreeze for winterization.
NOTE: The Aqua-Hot can continue to be used for interior
zone heating once the domestic water heating system
has been drained and winterized.
1. If the Diesel burner Fails to operate:
A. Is the Diesel Fuel in the motor home winter
fuel or summer fuel?
B. Is the Diesel Fuel liquid or Jelled?
C. Are the electrodes properly adjusted?
D. When was the last time an Annual Service
was performed?
120 Volt-A.C. Electric Heating Element
Please note that the 120 Volt-AC Electric Heating Element is
the Aqua-Hot’s secondary heat source for heating both the
interior and/or the domestic hot water during low heating demand situations (such as when moderate ambient temperatures
exist and/or when there is a low demand for domestic hot water).
If the 120 Volt-AC Electric Heating Element is not providing
enough heat, turn the Diesel-Burner on, in conjunction with the
120 Volt-AC Electric Heating Element.
Figure D1
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 100 —
APPENDIX D: EXTREME COLD WEATHER OPERATION
If there is a lack of interior Heat:
Note:
The 120 Volt-AC Electric Heating Element is
the Aqua-Hot’s secondary heat source for heating both
the interior and/or the domestic hot water during low heating demand situations (such as when moderate ambient
temperatures exist and/or when there is a low demand for
domestic hot water). If the ambient temperature is ex-
1. Is the Diesel Burner activated?
2. Is the Diesel Burner operating Properly?
3. What is the antifreeze concentration, inside of the
Aqua-Hot Boiler Tank?
4. Was the heating system properly installed, following the
600 installation manual?
Figure D2
A. Are there at least 5 heat exchangers installed
in the Interior of the motor home?
B. Are there cold air returns installed for every heat
exchanger? Reference Figure D3.
C. Are the heat exchangers mounted as close to the
hot air outlet grill as possible? Reference Figure D2.
Figure D3
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 101 —
APPENDIX E: AQUA-HOT MAINTENANCE
Monthly Maintenance:
Annual Maintenance:
Check the antifreeze and water heating solution to ensure
that it is at the proper level by visually checking the solution
level in the expansion tank. The level of the antifreeze and
water heating solution within the expansion tank should only
be checked when the Aqua-Hot is at maximum operating
temperature.
If additional antifreeze and water heating solution is required, fill the expansion tank to the “HOT” level mark. Be
sure to reference Section 2 of this manual to ensure that the
proper type of antifreeze is selected and mixed with highquality water at the correct mixture ratio.
Additionally, it is recommended that the diesel-burner be
fired and allowed to run monthly to keep it in good working
order.
FAILURE TO DISCONNECT ALL POWER SUPPLIES AND/OR
TO ALLOW THE HEATER TO COOL BEFORE SERVICING
COULD CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
To keep the Aqua-Hot running smoothly, it is recommended
to have the diesel-burner tuned up annually. A tune-up
should consist of a new fuel nozzle and fuel filter, along with
a thorough cleaning of the combustion chamber. To ensure
maximum diesel-burner performance, always use the recommended fuel nozzle and fuel filter when replacing these
parts.
NOTE: Be sure to use care when handling the fuel nozzle.
Oils and/or small dust or dirt particles from the
hands may plug the nozzle’s small orifice. A partially plugged orifice will restrict fuel flow, which
will affect the combustion process of the dieselburner.
Figure E1
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 102 —
APPENDIX E: AQUA-HOT MAINTENANCE
Aqua-Hot Maintenance Procedure:
Note: Before performing an annual
maintenance, it is recommended to test run
the Diesel-Burner. While testing inspect
exhaust for smoke.
Step 1: Test Run the Diesel Burner
1. Turn the Diesel-Burner Switch to the on
position.
2. After the Diesel-Burner has ignited, inspect
the exhaust for smoke.
3. Shut the Diesel-Burner off, and wait for unit
to completely shut off.
NOTE: The diesel-burner can either be shut off by:
1. Turning the Diesel Burner switch to the off position.
2. Disconnecting the control thermostat wires
3. Unplugging the diesel burner controller.
Reference Figure E3
Step 2: Replace the Fuel Filter
1. Locate Fuel Filter.
2. Using hose pinch off pliers, clamp off both
fuel lines going to the fuel filter. Reference
figure E2.
3. Replace fuel filter, with proper replacement
canister.
NOTE: It is recommended that the replacement fuel filter
be filled with clean diesel fuel, prior to installation
4. Remove hose pinch off pliers.
Step 3: Run the Diesel Burner
1. Turn the Diesel-Burner Switch to the on position.
2. After the Diesel-Burner has ignited, let it
burn for 1 - 2 minutes to purge the old fuel
out of the nozzle holder, to prevent contamination of the replacement nozzle.
3. Shut the Diesel-Burner off, and wait for unit
to completely shut off.
NOTE: The diesel-burner can either be shut off by:
1. Turning the Diesel Burner switch to the off position.
2. Disconnecting the control thermostat wires
3. Unplugging the diesel burner controller.
Reference Figure ??
Thermostat
Connector
Figure E3
Figure E2
Diesel Burner
Controller Plugs
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 103 —
APPENDIX E: AQUA-HOT MAINTENANCE
Aqua-Hot Maintenance Procedure:
Step 4: Remove The Diesel Burner
CAUTION!
Be sure to clamp off the Fuel Supply and Return lines at the ports on top of the Aqua-Hot prior to beginning this
replacement procedure.
Figure E4b
Figure E4a
Diesel Burner
Controller
1. Locate the Diesel-Burner’s Controller and disconnect both plugs.
Figure E4c
2. Using an 7/16 wrench, loosen the nuts securing
each fuel line to the Aqua-Hot.
Figure E4d
3. The Diesel-Burner is secured to the Aqua-Hot with two nuts that can be loosened, and swung out of
the way by using a 10mm socket wrench with a 10 inch long extension.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 104 —
APPENDIX E: AQUA-HOT MAINTENANCE
Aqua-Hot Maintenance Procedure:
Step 4: Remove The Diesel Burner (continued)
Figure E5
Diesel Burner’s white
Thermostat Plug
4. Carefully pull the Diesel-Burner away from the Aqua-Hot 4 to 5 inches before
rotating the burner, and then remove.
NOTE: To remove the diesel burner, it may be necessary to disconnect the control and hi limit thermostats from the diesel-burner’s white thermostat plug.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 105 —
APPENDIX E: AQUA-HOT MAINTENANCE
Step 5: Clean and Inspect the Combustion Chamber and Heat Transfer Tabs.
Use caution when handling the combustion chamber, it may be extremely
hot, and serious burns could result from touching a hot combustion chamber.
Figure E6
Combustion Chamber
Assembly
Combustion Chamber
Gasket
Air Swirler
Nut Securing the
Combustion Chamber
1. Remove the combustion chamber by loosening and
removing the 4 nuts, securing the combustion chamber
to the boiler tank and pulling it straight out, approximately 16 inches.
2. Once the combustion chamber has been removed.
Use a long handled wire brush, and brush the heat transfer tabs, to loosen soot deposits. Failure to do so will
reduce the Aqua-Hot’s heat transfer capabilities.
NOTE: If the heat transfer tabs are excessively sooty, it may be necessary to vacuum the soot out of the heat transfer
tabs. If there is a minimal amount of soot, it may be left in the heat transfer tabs, and will be evacuated out the exhaust
pipe, upon start up of diesel burner.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 106 —
APPENDIX E: AQUA-HOT MAINTENANCE
Step 5: Clean and Inspect the Combustion Chamber and Heat Transfer Tabs.
Combustion Chamber
Assembly
Figure E7
Back side of air
swirler
Outer ring that the photo
disc seats against
3. Inspect the Combustion Chamber Assembly and Air Swirler for damage or signs of warping.
1. Remove and Inspect the aluminum Air Swirler for signs of warping. If any part of the Air Swirler is
warped the Air Swirler must be replace.
A. Inspect the outer ring that the photo disc seats against for signs of warping.
B. Inspect the back side of the Air Swirler for signs of warping between screws.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 6: Reinstall the Combustion Chamber
CAUTION!
Failure to reinstall the combustion chamber will result in serious damage to the diesel burner.
Combustion Chamber
Assembly
Figure E8
Combustion Chamber
Gasket
Air Swirler
1. Reinstall the Combustion Chamber Assembly and the Air Swirler into the Aqua-Hot. Please note: It will
be necessary to replace the combustion chamber gasket, anytime the combustion chamber is removed.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 6: Inspect Diesel-Burner
Figure E9
Electrode
Fuel Nozzle
Fuel Pump
Grommet
Photo Disc
Ear
Flame Sensor
Inspect the following:
1.
Electrodes
- damaged
- improperly adjusted
2.
Fuel Pump
- leaks
3.
Photo disc
- warped
- bent
4.
Harness & Ignition Coil Wires
- crack or bare wires
- Hard or brittle wires
5.
Flame Sensor
- cracked
- overheated (purple color)
- melted wires
- dirty
6.
Rubber Grommets
- hard/brittle
- rubber has been cut out
- right/left
7.
Broken or cracked “Ears”
- due to over tightening of eyebolts.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 7: Clean Ignition Electrodes and Flame Sensor
Metal Tips
Figure E10
Flame Sensor
1.
Ignition electrodes A. Polish away any carbon deposits that may have baked onto the metal tips of the ignition
electrodes with a course sponge.
2.
Flame Sensor A. For light dirt, dust, and/or carbon deposits, simply wipe off the flame sensor with a soft
cloth.
B. Should heavy carbon deposits be present, completely remove the flame sensor from the
photo disc and clean with brake cleaner.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 8: Replace The Fuel Nozzle
Figure E11
1. Use a 3/4 in. wrench to hold the fuel nozzle manifold hex, while loosening the fuel nozzle with a 5/8 in. wrench and remove.
NOTE: Be sure to use care when handling the new fuel nozzle. Oils and/or small dust or dirt particles from your hands may plug
the nozzle’s small orifice. A partially plugged orifice will restrict fuel flow, which will affect the combustion process of
the diesel-burner.
2.
When replacing the fuel nozzle, be sure to tighten the nozzle, loosen it a 1/4 turn, and then firmly retighten. This will establish a seated fit and avoid any leaks.
Be sure to reattach the diesel-burner head prior to switching
the heater ON. Failure to do so may result in ignition of the
diesel-burner and serious bodily injury.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 9. Adjust Ignition Electrodes
Figure E12
1.
Using a 10mm socket, slightly loosen the retaining clamp bolt.
2. Place the electrode adjustment gauge on the nozzle manifold hex and insert the metal tips of the ignition electrodes into the
appropriate notches of the electrode adjustment gauge.
3.
Using a 10 mm socket, tighten the retaining clamp bolt.
NOTE: Be sure not to over-tighten the retaining clamp bolt when readjusting the ignition electrodes. Over-tightening the retaining
clamp bolt will bend the retaining clamp and prevent the photo disc from floating freely. Not allowing the photo disc to
float freely will cause poor combustion and result in a smoky exhaust. A bent retaining clamp can be re-straightened with a
punch and hammer. Lay the clamp’s beveled side down on a solid flat surface and align the thick end of the punch at dead
center. Tap the punch lightly until the retaining clamp returns to proper form.
4. Remove the electrode adjustment gauge.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 10: Inspect Photo Disc
Figure E13
Photo Disc
1.
If the photo disc is not free floating, the electrode clamp bolt has been over-tightened, and has bent the electrode clamp. Using a
10mm socket remove the electrode clamp, and re-straighten.
-Lay the clamp’s beveled side down on a solid flat surface and align the thick end of the punch at dead center. Tap the
punch lightly until the retaining clamp returns to proper form.
Step 11: Re-Install Diesel Burner
Figure E14a
Figure E14b
NOTE: When reinstalling the diesel burner be careful not to damage the photo disc or bend the electrodes.
Also, be careful to not pinch any wires between the burner and the Aqua-Hot Tank.
1. Align the Diesel-Burner with the Aqua-Hot, using the alignment tabs welded on the Aqua-Hot.
2. Swing the Eye Bolts around the “Ears” on the diesel burner and securely tighten, using a 10mm socket with a 10
inch long extension.
Use extreme caution when tightening down the eye-bolt nuts, over tightening of the eye-bolt nuts can
cause the aluminum blower casing to crack. (Torque Specifications = Approximately 20-40 in. lbs.)
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 12: Reconnect the Fuel Lines
Figure E15
1. Align the fuel lines on the diesel burner with the fittings on the Aqua-Hot, and using a 7/16 inch
wrench, tighten down both the supply and return fuel fittings.
CAUTION!
Be sure to remove the clamps, off of the Fuel Supply and Return lines at the ports on top of the Aqua-Hot prior to starting the diesel burner, or serious damage will occur to the diesel-burner’s fuel pump.
Step 13: Plug in the diesel-burner’s controller and mount
Figure E16
Control Unit
1. Locate the Diesel-Burner’s Controller and connect both plugs.
NOTE: The Diesel Burner’s Controller might have to be mounted onto the side of the diesel burner, before the
plugs are inserted into the control unit, otherwise it might not be possible to mount the control unit.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX E: AQUA-HOT MAINTENANCE
Step 14: Re-Install the Aqua-Hot Access Cover
NOTE: The access cover must be installed prior to operation as a safety switch exists, which will prevent the
Aqua-Hot from operating whenever the access cover is not properly installed.
Figure E17a
Figure E17b
1. Reinstall the Aqua-Hot’s access cover .
2. Securely tighten the four screws securing the
access cover in place.
Step 15: Test for Normal Operation
A. Turn the Diesel-Burner switch on, and let the diesel burner run for a complete cycle, until it shuts
off on it’s own.
B. After the Diesel-Burner has shut off, turn on the interior heat/run hot water, until the Diesel
Burner cycles back on. When the diesel burner cycles back on, check the exhaust for signs of
smoke.
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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APPENDIX F: WINTERIZATION
Figure F1
© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
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© 2010 Aqua-Hot® 600-D03 Hydronic Heating System Service Manual—Rev. A
— Page 117 —
SERVICE MANUAL
15549 East Highway 52 | Fort Lupton, CO 80621
Toll free: 800.685.4298 | phone: 303.659.8221 | fax:303.857.7881
www.aquahot.com
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