CENTURY HNW Series Water Source Heat Pumps Instruction manual

Installation, Operation &
Maintenance
Geothermal Open Loop Water-toWater HNW Series
Water-to-Water
Water-Source Heat Pumps
97B0123N02
Issue Date: January 24, 2023
Installation, Operation & Maintenance - HNW Water to Water Series
Table of Contents
2
Model Nomenclature
3
Safety
4
General Information
4
Physical Data
6
Dimensional Data
7
Unit Installation
8
Water Connection Installation
8
Ground-Water Heat Pump Applications
9
Water Quality Requirements
11
Load Side Plumbing Installation
14
Hot Water Generator
15
Electrical – Line Voltage
18
Electrical – Low Voltage Wiring
19
Controls – DXM2.5
20
Unit Commissioning & Operating Limits
21
Unit & System Checkout
22
Unit Start-Up Procedure
23
Operating Pressures
25
Preventive Maintenance
27
Troubleshooting Form
28
Warranty
29
Revision History
32
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Model Nomenclature
1
2
HN
3
4 5 6
W 036
7
A
8
1
9
C
10
1
11
12
1
C
13
F
14
B
Series
HN = Heat Controller High Efficiency
Load Water Coil
Configuration
C = Copper
N = Cupro-Nickel
W = Water To Water
Unit Size
Water Connection Location
036
060
120
F = Front
Source Water Coil
Revision Level
N = Cupro-Nickel
A = Current Revision
Hot Water Generator
0 = None
Voltage
1 = 208-230/60/1
Cabinet
Controls
0 = Residential
D = DXM2.5
⚠ WARNING! ⚠
WARNING! HNW IS FOR GROUND WATER
INSTALLATIONS ONLY. Installing HNW on closed loop system
will void warranty and unit will not be eligible for federal tax credit.
Installation, Operation, Maintenance
3
Installation, Operation & Maintenance - HNW Water to Water Series
General Information
SAFETY
Warnings, cautions and notices appear throughout this
manual. Read these items carefully before attempting any
installation, service, or troubleshooting of the equipment.
DANGER: Indicates an immediate hazardous situation, which
if not avoided will result in death or serious injury. DANGER
labels on unit access panels must be observed.
WARNING: Indicates a potentially hazardous situation, which
if not avoided could result in death or serious injury.
CAUTION: Indicates a potentially hazardous situation or an
unsafe practice, which if not avoided could result in minor or
moderate injury or product or property damage.
NOTICE: Notification of installation, operation or maintenance
information, which is important, but which is not hazardrelated.
⚠ WARNING! ⚠
⚠ WARNING! ⚠
WARNING! All refrigerant discharged from this unit must
be recovered WITHOUT EXCEPTION. Technicians must
follow industry accepted guidelines and all local, state,
and federal statutes for the recovery and disposal of
refrigerants. If a compressor is removed from this unit,
refrigerant circuit oil will remain in the compressor. To
avoid leakage of compressor oil, refrigerant lines of the
compressor must be sealed after it is removed.
⚠ CAUTION! ⚠
CAUTION! To avoid equipment damage, DO NOT use
these units as a source of heating or cooling during the
construction process. The mechanical components and
filters can quickly become clogged with construction dirt
and debris, which may cause system damage and void
product warranty.
WARNING! To avoid the release of refrigerant into the
atmosphere, the refrigerant circuit of this unit must be
serviced only by technicians who meet local, state, and
federal proficiency requirements.
The following warning complies with State of California law,
Proposition 65.
⚠ WARNING! ⚠
WARNING! This product can expose you to chemicals
including Carbon Black, which is known to the State of
California to cause cancer and Methanol, which is known
to the State of California to cause birth defects or other
reproductive harm. For more information go to
www.P65Warnings.ca.gov
4
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
General Information, Cont'd.
INSPECTION
Upon receipt of the equipment, carefully check the shipment
against the bill of lading. Make sure all units have been
received. Inspect the carton or crating of each unit, and
inspect each unit for damage. Assure the carrier makes
proper notation of any shortages or damage on all copies of
the freight bill and completes a common carrier inspection
report. Concealed damage not discovered during unloading
must be reported to the carrier within 15 days of receipt
of shipment. If not filed within 15 days, the freight
company can deny the claim without recourse. Note: It
is the responsibility of the purchaser to file all necessary
claims with the carrier. Notify the Heat Controlller Traffic
Department of all damage within fifteen (15) days of
shipment.
STORAGE
Equipment should be stored in its original packaging in a
clean, dry area. Store units in an upright position at all times.
The stack limit for HNW036, 060 and 120 is three.
⚠ CAUTION! ⚠
CAUTION! DO NOT store or install units in corrosive
environments or in locations subject to temperature or
humidity extremes (e.g., attics, garages, rooftops, etc.).
Corrosive conditions and high temperature or humidity
can significantly reduce performance, reliability, and
service life. Always move and store units in an upright
position. Tilting units on their sides will cause equipment
damage.
⚠ CAUTION! ⚠
CAUTION! CUT HAZARD - Failure to follow this caution
may result in personal injury. Sheet metal parts may have
sharp edges or burrs. Use care and wear appropriate
protective clothing, safety glasses and gloves when
handling parts and servicing heat pumps.
UNIT PROTECTION
Cover units on the job site with either shipping packaging,
vinyl film, or an equivalent protective covering. Cap the open
ends of pipes stored on the job site. In areas where painting,
plastering, and/or spraying has not been completed, all due
precautions must be taken to avoid physical damage to the
units and contamination by foreign material. Physical damage
and contamination may prevent proper start-up and may
result in costly equipment clean-up.
Examine all pipes, fittings, and valves before installing any of
the system components. Remove any dirt or trash found in or
on these components.
PRE-INSTALLATION
Installation, Operation, and Maintenance instructions are
provided with each unit.. The installation site chosen should
include adequate service clearance around the unit. Before
unit start-up, read all manuals and become familiar with
the unit and its operation. Thoroughly check the system
before operation.
PREPARE UNITS FOR INSTALLATION AS FOLLOWS:
1. Compare the electrical data on the unit nameplate with
ordering and shipping information to verify that the
correct unit has been shipped.
2. Keep the cabinet covered with the shipping packaging
until installation is complete and all plastering, painting,
etc. is finished.
3. Verify refrigerant tubing is free of kinks or dents and that
it does not touch other unit components.
4. Inspect all electrical connections. Connections must be
clean and tight at the terminals.
Installation, Operation, Maintenance
5
Installation, Operation & Maintenance - HNW Water to Water Series
Physical Data
Model
036
Compressor (qty)
Factory Charge HFC-410A (oz) [kg] Per
Circuit
060
Scroll (1)
72 [2.04]
120
Scroll (2)
96 [2.49]
96 [2.49]
Water Connection Size
Source/Load
1" Swivel
HWG (in)
1" Swivel
1-1/2 FPT
1/2" FPT
Weight - Operating (lbs) [kg]
348 [158]
360 [163]
726 [329]
Weight - Packaged (lbs) [kg]
373 [169]
385 [175]
770 [349]
0.96 (3.64)
1.33 (5.04)
2.65 (10.02)
Water Volume (Source)
Gallons (Liters)
Dual isolated compressor mounting
Balanced port expansion valve (TXV)
Insulated Source and Load Water Coils standard
Insulated Refrigerant Circuit standard
Compressor on (green) and fault (red) light
6
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Dimensional Data
B
5
1.0
(2.5 cm)
C
TMW
036-060
M
L
K
Required
Service Access
Optional
Service Access
3 Ft
Notes 1 & 2
TMW
036-060
F
2
L
K
Required
Service Access
G
H
J
A
Depth
B
Width
D
E
C
Source
Source
Height (Outdoor) (Outdoor)
Water In Water Out
6
1
4
L
2.9
(7.4 cm)
4.0
(10.1 cm)
Required
Service Access
HNW 120
Water Connections
2
3
TMW 120
M
3 Ft
Notes 1 & 2
Optional
Service Access
1
(4.3 cm)
5
3 Ft
Notes 1 & 2
Overall Cabinet
120
C
D
Notes 1 &1.7
2
2
K
3 Ft
Notes 1 & 2
Water to
Water
A
2.7
(6.9 cm)
E
1
036-060
Optional
Service Access
1.3
(3.3 cm)
3
Required
Service Access
7.2
(18.3 cm)
3 Ft
B
4
&2
3 Ft
Notes 1 & 2
6
1.0
(2.5 cm)
M
D
(4.6 cm)
5
1.0
(2.5 cm)
C
1
K
HNW 036,
1.8 060
A
J
E
1
3 Ft
Notes 1 & 2
B
F
2
G
H
3
Notes:
1.3
1. 3 feet front
access is required, both sides access
(3.3preferred
cm) for service access. However,
is optional
all components may be serviced from the front
access panel if side access is not available.
2. While clear access to all removable panels is not TMW 120
required, installer should take care to comply
M with
all building codes and allow adequate clearance
L
for future field services.
4
3
5
2.7
(6.9 cm)
6
1.0
(2.5 cm)
A
B
1.8
(4.6 cm)
A
7
(18.3
Electric Access Plugs
3
4
5
6
F
Load
(Indoor)
Water In
G
Load
(Indoor)
Water Out
H
HWG
Water In
J
HWG
Water
Out
K
Low
Voltage
L
External
Pump
M
Power
Supply
in.
30.6
25.4
33
2.7
9.4
19.4
24.5
27.9
30.4
20.9
22.9
30.9
cm.
77.8
64.5
83.8
6.9
23.9
49.3
62.2
70.9
77.2
53.1
58.2
78.5
in.
30.6
52.9
37
25.2
25.2
30.1
30.1
34.9
34.9
29.9
31.9
34.4
cm.
77.8
134.4
94
64.0
64.0
76.5
76.5
88.6
88.6
75.9
81.0
87.4
Installation, Operation, Maintenance
7
Installation, Operation & Maintenance - HNW Water to Water Series
Unit Installation
UNIT LOCATION
These units are not designed for outdoor installation. Locate
the unit in an INDOOR area that allows enough space for
service personnel to perform typical maintenance or repairs.
The installation of water source heat pump units and all
associated components, parts and accessories which
make up the installation shall be in accordance with
the regulations of ALL authorities having jurisdiction
and MUST conform to all applicable codes. It is the
responsibility of the Installing Contractor to determine and
comply with ALL applicable codes and regulations.
Locate the unit in an indoor area that allows easy removal of
access panels, and has enough space for service personnel
to perform maintenance or repair. Provide sufficient room
to make water and electrical connections. Any access panel
screws that would be difficult to remove after the unit is
installed should be removed prior to setting the unit. These
units are not approved for outdoor installation and, therefore,
must be installed inside the structure being conditioned. Do
not locate in areas subject to freezing or where humidity
levels can cause cabinet condensation.
WATER CONNECTION INSTALLATION
Residential models using swivel piping fittings for water
connections are rated for 450 psi (3101 kPa) operating
pressure. The connections have a rubber gasket seal similar
to a garden hose gasket, which when mated to the flush
end of most 1” threaded male pipe fittings provides a
leak-free seal without the need for thread sealing tape or
joint compound. Insure that the rubber seal is in the swivel
connector prior to attempting any connection (rubber seals
are shipped attached to the swivel connector). DO NOT
OVER TIGHTEN or leaks may occur.
FPT CONNECTIONS (SIZE 120)
Pipe joint compound is not necessary when Teflon threaded
tape is pre-applied to hose assemblies or when flared-end
connections are used. If pipe joint compound is preferred,
use compound only in small amounts on the pipe threads of
the fitting adapters. Prevent sealant from reaching the flared
surfaces of the joint.
NOTE: When antifreeze is used in the loop, assure that
it is compatible with Teflon tape or pipe joint compound
employed.
Maximum allowable torque for brass fittings is 30 ft-lbs [41
N-m]. If a torque wrench is not available, tighten finger-tight
plus one quarter turn. Tighten steel fittings as necessary.
8
The female locking ring is threaded onto the pipe threads
which holds the male pipe end against the rubber gasket,
and seals the joint. HAND TIGHTEN ONLY! DO NOT
OVERTIGHTEN!
Swivel Nut
Stainless steel
snap ring
Hand Tighten
Only!
Do Not
Overtighten!
Gasket
Brass Adaptor
⚠ WARNING! ⚠
WARNING! Polyolester Oil, commonly known as POE
oil, is a synthetic oil used in many refrigeration systems
including those with HFC-410A refrigerant. POE oil, if it
ever comes in contact with PVC or CPVC piping, may
cause failure of the PVC/CPVC. PVC/CPVC piping should
never be used as supply or return water piping with water
source heat pump products containing HFC-410A as
system failures and property damage may result.
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Ground-Water Heat Pump Applications
OPEN LOOP: GROUND-WATER SYSTEMS
Typical open loop piping is shown in Figure 2. Shut off valves
should be included for ease of servicing. Boiler drains or
other valves should be “tee’d” into the lines to allow acid
flushing of the heat exchanger. Shut off valves should be
positioned to allow flow through the coaxial heat exchanger
via the boiler drains without allowing flow into the piping
system. P/T plugs should be used so that pressure drop and
temperature can be measured. Supply and return water
piping should be limited to copper, HPDE, or other acceptable
high temperature material. Note that PVC or CPVC material
is not recommended as they are not compatible with the
polyolester oil used in HFC-410A products.
recharge well, storm sewer, drain field, adjacent stream
or pond, etc.). Most local codes forbid the use of sanitary
sewer for disposal. Consult your local building and zoning
department to assure compliance in your area.
Water quantity should be plentiful and of good quality.
Consult water quality table for guidelines. The unit comes
standard with either a copper or cupro-nickel source water
heat exchanger. Consult Table 1 for recommendations. In
conditions anticipating heavy scale formation or in brackish
water, a cupro-nickel heat exchanger is recommended. In
ground water situations where scaling could be heavy or
where biological growth such as iron bacteria will be present,
an open loop system is not recommended. Heat exchanger
coils may over time lose heat exchange capabilities due to
build up of mineral deposits. Heat exchangers must only
be serviced by a qualified technician, as acid and special
pumping equipment is required. Desuperheater coils can
likewise become scaled and possibly plugged. In areas with
extremely hard water, the owner should be informed that
the heat exchanger may require occasional acid flushing.
In some cases, the desuperheater option should not be
recommended due to hard water conditions and additional
maintenance required.
WATER CONTROL VALVE
Always maintain water pressure in the heat exchanger
by placing the water control valve(s) on the discharge line
to prevent mineral precipitation during the off-cycle. Pilot
operated slow closing valves are recommended to reduce
water hammer. If water hammer persists, a mini-expansion
tank can be mounted on the piping to help absorb the excess
hammer shock. Insure that the total ‘VA’ draw of the valve
can be supplied by the unit transformer. For instance, a slow
closing valve can draw up to 35VA. This can overload smaller
40 or 50 VA transformers depending on the other controls
in the circuit. A typical pilot operated solenoid valve draws
approximately 15VA. Note the special wiring diagrams later
in this manual for slow closing valves.
WATER QUALITY REQUIREMENTS
Scaling potential should be assessed using the pH/
Calcium hardness method. If the pH < 7.5 and the Calcium
hardness is less than 100 ppm, scaling potential is low. If
this method yields numbers out of range of those listed, the
Ryznar Stability and Langelier Saturation indexes should be
calculated. Use the appropriate scaling surface temperature
for the application, 150°F [66°C] for direct use (well water/
open loop) and HWG (desuperheater); 85°F [29°C] for
indirect use. A monitoring plan should be implemented in
these probable scaling situations. Other water quality issues
such as iron fouling, corrosion prevention and erosion and
clogging should also be considered.
EXPANSION TANK AND PUMP
Use a closed, bladder-type expansion tank to minimize
mineral formation due to air exposure. The expansion tank
should be sized to provide at least one minute continuous
run time of the pump using its drawdown capacity rating to
prevent pump short cycling. Discharge water from the unit
is not contaminated in any manner and can be disposed
of in various ways, depending on local building codes (e.g.
The pump should be sized to handle the home’s domestic
water load (typically 5-9 gpm [23-41 l/m]) plus the flow
rate required for the heat pump. Pump sizing and expansion
tank must be chosen as complimentary items. For example,
an expansion tank that is too small can causing premature
pump failure due to short cycling. Variable speed pumping
applications should be considered for the inherent energy
savings and smaller expansion tank requirements.
FLOW REGULATION
Flow regulation can be accomplished by two methods. One
method of flow regulation involves simply adjusting the ball
valve or water control valve on the discharge line. Measure
the pressure drop through the unit heat exchanger, and
determine flow rate from tables located later in this manual.
Since the pressure is constantly varying, two pressure
gauges may be needed. Adjust the valve until the desired
flow of 1.5 to 2 gpm per ton [2.0 to 2.6 l/m per kW] is
achieved. A second method of flow control requires a flow
control device mounted on the outlet of the water control
valve. The device is typically a brass fitting with an orifice of
rubber or plastic material that is designed to allow a specified
flow rate. On occasion, flow control devices may produce
velocity noise that can be reduced by applying some back
pressure from the ball valve located on the discharge line.
Slightly closing the valve will spread the pressure drop over
both devices, lessening the velocity noise. NOTE: When
EWT is below 50°F [10°C], a minimum of 2 gpm per ton
(2.6 l/m per kW) is required.
LOAD WATER COIL LOW TEMPERATURE LIMIT SETTING
For all open loop systems, if the leaving water is below 40°F
(4.4°C), must use antifreeze and clip JW2 (factory settingwater) to avoid freeze damage to the unit. See “Low Water
Temperature Cutout Selection” in this manual for details on
the low limit setting.
Installation, Operation, Maintenance
9
Installation, Operation & Maintenance - HNW Water to Water Series
Ground-Water Heat Pump Applications, Cont'd.
⚠ CAUTION! ⚠
CAUTION! Many units are installed with a factory or field
supplied manual or electric shut-off valve. DAMAGE WILL
OCCUR if shut-off valve is closed during unit operation. A
high pressure switch must be installed on the heat pump
side of any field provided shut-off valves and connected to
the heat pump controls in series with the built-in refrigerant
circuit high pressure switch to disable compressor
operation if water pressure exceeds pressure switch
setting. The field installed high pressure switch shall
have a cut-out pressure of 300 psig and a cut-in pressure
of 250 psig. This pressure switch can be ordered from
Heat Controller with a 1/4” internal flare connection as part
number 39B0005N02.
⚠ CAUTION! ⚠
CAUTION! Refrigerant pressure activated water regulating
valves should never be used with Heat Controlller
equipment.
Figure 2: Typical Open Loop/ Well Application
Unit Power
Disconnect
Flow
Water
Control Regulator
Valve
Air Pad or
Extruded
polystyrene
insulation board
Pressure
Tank
Water Out
Water In
Shut-Off
Valve
Optional
Filter
P/T Plugs
Boiler
Drains
Aquastat and Change Over Wiring
10
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Water Quality Requirements
Table 1: Water Quality Requirements
Clean water is essential to the performance and life span of water source heat pumps. Contaminants, chemicals, and minerals
all have the potential to cause damage to the water heat exchanger if not treated properly. All closed water loop systems
should undergo water quality testing and be maintained to the water quality requirements listed in this table.
WATER QUALITY REQUIREMENTS
Electrolysis
All HX types
Fouling &
Biological
Corrosion Preven�on
Scaling Poten�al
For Closed-Loop and Open-Loop Systems
Descrip�on
Symbol
Units
pH - Chilled Water <85°F
pH - Heated Water >85°F
(HCO3-) ppm - CaCO3 equiv.
Alkalinity
Calcium
(Ca)
ppm
Magnesium
(Mg)
ppm
Total Hardness
(CaCO3) ppm - CaCO3 equiv.
Langelier Satura�on Index LSI
Ryznar Stability Index
RSI
ppm - CaCO3 equiv.
Total Dissolved Solids
(TDS)
(SO42-) ppm
Sulfate
(NO3-) ppm
Nitrate
Chlorine (free)
(Cl)
ppm
Chloride (water < 80°F)
ppm
(Cl )
Chloride (water > 120°F)
ppm
α
Hydrogen Sulfide
(H2S)
ppb
Carbon Dioxide
Iron Oxide
Manganese
Ammonia
Chloramine
Iron Bacteria
Slime Forming Bacteria
Sulfate reducing bacteria
Suspended Solidsβ
(CO2)
Heat Exchanger Type
Closed Loop
Open Loop, Tower, Ground Source Well
Recircula�ng
All Heat Exchanger COAXIAL HX Copper COAXIAL HX Brazed Plate HX
Types
Tube in Tube
Cupronickel
316 SS
7.0 to 9.0
7.0 to 9.0
7.0 to 9.0
7.0 to 9.0
8.0 to 10.0
8.0 to 10.0
8.0 to 10.0
8.0 to 10.0
50 to 500
50 to 500
50 to 500
50 to 500
<100
<100
<100
<100
<100
<100
<100
<100
30 to 150
150 to 450
150 to 450
150 to 450
-0.5 to +0.5
-0.5 to +0.5
-0.5 to +0.5
-0.5 to +0.5
6.5 to 8.0
6.5 to 8.0
6.5 to 8.0
6.5 to 8.0
<1000
<1000
<1000
<1500
<200
<200
<200
<200
<100
<100
<100
<100
<0.5
<0.5
<0.5
<0.5
<20
<20
<150
<150
<20
<20
<125
<125
<0.5
<0.5
<0.5
<0.5
(Fe)
(Mn)
(NH3)
(NH2CL)
ppm
ppm
ppm
ppm
ppm
0
<1.0
< 0.4
<0.05
0
<50
<1.0
<0.4
<0.1
0
10 to 50
<1.0
<0.4
<0.1
0
10 to 50
<0.2
<0.4
<0.1
0
(TSS)
cells/mL
cells/mL
cells/mL
ppm
0
0
0
<10
0
0
0
<10
0
0
0
<10
0
0
0
<10
Earth Ground Resistanceχ
Ohms
0
Electrolysis Voltageδ
Leakage Currentδ
mV
mA
<300
<15
Consult NEC & local electrical codes for grounding requirements
Measure voltage internal water loop to HP ground
Measure current in water loop pipe
Building Primary Electrical Ground to unit, must meet local diameter and penetra�on length requirements
Do not connect heat pump to steel pipe unless dissimilar materials are separated by using Di-electric unions. Galvanic corrosion of heat
pump water pipe will occur.
Installation, Operation, Maintenance
11
Installation, Operation & Maintenance - HNW Water to Water Series
Water Quality Requirements, Cont'd.
1.
2.
3.
4.
5.
6.
7.
The Heat Controlller Water Quality Table provides water
quality requirements for coaxial & brazed plate heat
exchangers.
The water must be evaluated by an independent testing
facility comparing site samples against this Table. When
water properties are outside of these parameters, the
water must either be treated by a professional water
treatment specialist to bring the water quality within
the boundaries of this specification, or an external
secondary heat exchanger must be used to isolate the
heat pump water system from the unsuitable water.
Failure to do so will void the warranty of the heat pump
system and will limit liability for damage caused by leaks
or system failure.
Regular sampling, testing and treatment of the water
is necessary to assure that the water quality remains
within acceptable levels thereby allowing the heat pump
to operate at optimum levels.
If closed‐loop systems are turned off for extended
periods, water samples must be tested prior to operating
the system.
For optimal performance, it is recommended that the
closed‐loop piping systems are initially filled with de‐
ionized water.
Well water with chemistry outside of these boundaries,
and salt water or brackish water requires an external
secondary heat exchanger. Surface/Pond water should
not be used.
If water temperature is expected to fall below 40°F,
antifreeze is required. Refer to the heat pump IOM for
the correct solution ratios to prevent freezing.
α
β
χ
δ
Hydrogen Sulfide has an odor of rotten eggs. If one
detects this smell, a test for H2S must be performed. If
H2S is detected above the limit indicated, remediation is
necessary (Consult with your Water Testing/Treatment
Professional) or a secondary heat exchanger is required
using appropriate materials as recommended by the
heat exchanger supplier.
Suspended solids and particulates must be filtered to
prevent fouling and failure of heat exchangers. Strainers
or particulate filters must be installed to provide a
maximum particle size of 600 micron (0.60 mm, 0.023
in.) using a 20 to 30 mesh screen size. When a loop is
installed in areas with fine material such as sand or clay,
further filtration is required to a maximum of 100 micron.
Refer to the Strainer / Filter Sizing Chart to capture the
particle sizes encountered on the site.
An electrical grounding system using a dedicated
ground rod meeting NEC and Local Electrical codes must
be installed. Building Ground must not be connected the
WSHP piping system or other plumbing pipes.
Refer to IOM for instructions on measuring resistance
and leakage currents within water loops.
Do not use PVC pipe for water loop (compressor POE
oil and glycols damage PVC) use of HDPE pipe is
recommended.
Strainer / Filter Sizing
Mesh Size
Particle Size
Microns
MM
Inch
20
840
0.840
0.0340
30
533
0.533
0.0210
60
250
0.250
0.0100
100
149
0.149
0.0060
150
100
0.100
0.0040
200
74
0.074
0.0029
ppm = parts per million
ppb = parts per billion
12
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Water Quality Requirements, Cont'd.
Measuring Earth Ground Resistance
0.02�
Well Casing
Building
Ground Rod
OHM meter
Measure the earth ground bond using an Ohm meter between the building's ground rod and the steel well casing.
The resistance measured should be zero Ohms. The NEC allows a resistance to ground up to 20 Ohms. Any
resistance above zero, indicates a poor earth ground which may be the result of a hot neutral line or that
conduc�ve water is present. Both of these may lead to electrolysis and corrosion of the heat pump piping. A check
for both should be performed and resolved.
Note if the well casing is plas�c, a conduc�ve path can be achieved by inser�ng a #6 AWG bare copper wire into the
well water. Remove the temporary conductor when finished.
Measuring Electrolysis Voltage and Current
300mV
Heat Pump
Volt Meter
Wire Electrode inserted into port for
Voltage measurement
Pete's Port
Water-in
Water-out
Amp Sensor to VOM for Current
HP Piping
Measure the electrolysis voltage using a volt meter between the heat pump ground and a #14 AWG solid copper
wire electrode inserted into the water using a Pete’s style access port.
The HP must be opera�ng and the water stream flowing.
The voltage measured should be less than 300mV (0.300 V). If higher than 500mV electrolysis will occure and
corrosion will result.
If voltage is measured, the cause is a high resistance earth ground or current on the neutral conductor. Remedial
measures should be performed.
Measure the current flowing through the piping system by using an amp clamp probe on the water-in line. The HP
must be opera�ng and the water stream flowing.
There should be zero amps measured. If current is present, there is leakage current to the plumbing system and it
must be rec�fied to prevent pipe corrosion.
Installation, Operation, Maintenance
13
Installation, Operation & Maintenance - HNW Water to Water Series
Load Side Plumbing Installation
HNW UNIT LOAD PLUMBING
The applications are too varied to describe in this document.
However, some basic guidelines will be presented. All plumbing
should conform to local codes with the following considerations:
Wide temperature variation applications such as heating/
cooling coils:
• Employ piping materials that are rated for the
maximum temperature and pressure combination.
This excludes PVC for most heating applications.
• Insure that load water flow in high temperature
heating applications is at least 3 gpm per ton [3.9 l/m
per kW] to improve performance and reduce nuisance
high pressure faults.
• DO NOT employ plastic to metal threaded joints
• Utilize a pressure tank and air separator vent system
to equalize pressure and remove air.
NOTE: The manufacturer strongly recommends all piping
connections, both internal and external to the unit, be
pressure tested by an appropriate method prior to any
finishing of the interior space or before access to all
connections is limited. Test pressure may not exceed
the maximum allowable pressure for the unit and all
components within the water system. The manufacturer
will not be responsible or liable for damages from water
leaks due to inadequate or lack of a pressurized leak test,
or damages caused by exceeding the maximum pressure
rating during installation.
Swimming Pool Hot Tub Applications:
• Load side should be isolated with secondary heat
exchanger constructed of anti-corrosion material in all
chlorine/bromine fluid applications.
Potable Water Applications:
• Load side should always be isolated with secondary
heat exchanger for use in potable water systems.
• Insure load water flow in high temperature heating
applications is at least 3 gpm per ton to improve
performance and reduce nuisance to high
pressure faults.
14
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Hot Water Generator
The HWG (Hot Water Generator) or desuperheater option
provides considerable operating cost savings by utilizing
heat energy from the compressor discharge line to help
satisfy domestic hot water requirements. The HWG is active
throughout the year, providing virtually free hot water when
the heat pump operates in the cooling mode or hot water at
the COP of the heat pump during operation in the heating
mode. Actual HWG water heating capacities are provided in
the appropriate heat pump performance data.
Heat pumps equipped with the HWG option include a builtin water to refrigerant heat exchanger that eliminates the
need to tie into the heat pump refrigerant circuit in the field.
The control circuit and pump are also built in for residential
equipment. Figure 3 shows a typical example of HWG water
piping connections on a unit with built-in circulating pump.
This piping layout prevents sludge/debris from the bottom of
the tank being pulled into the HWG pump.
The temperature setpoint of the HWG is field selectable
to 125°F or 150°F. The 150°F setpoint allows more heat
storage from the HWG. For example, consider the amount of
heat that can be stored by the HWG when using the 125°F
setpoint, versus the amount of heat that can be generated by
the HWG when using the 150°F setpoint.
In a typical 50 gallon two-element electric water heater
the lower element should be turned down to 100°F, or the
lowest setting, to get the most from the HWG. The tank will
eventually stratify so that the lower 80% of the tank, or 40
gallons, becomes 100°F (controlled by the lower element).
The upper 20% of the tank, or 10 gallons, will be maintained
at 125°F (controlled by the upper element).
Figure 3: Typical HWG Installation
Using a 125°F setpoint, the HWG can heat the lower 40
gallons of water from 100°F to 125°F, providing up to 8,330
btu’s of heat. Using the 150°F setpoint, the HWG can heat
the same 40 gallons of water from 100°F to 150°F and
the remaining 10 gallons of water from 125°F to 150°F,
providing a total of up to 18,743 btu’s of heat, or more than
twice as much heat as when using the 125°F setpoint.
Electric water heaters are recommended. If a gas, propane,
or oil water heater is used, a second preheat tank must be
installed (Figure 4). If the electric water heater has only a
single center element, the dual tank system is recommended
to insure a usable entering water temperature for the HWG.
Typically a single tank of at least 50 gallons (189 liters) is
used to limit installation costs and space. However, a dual
tank, as shown in Figure 4, is the preferred system, as it
provides the maximum storage and temperate source water
to the HWG.
It is always advisable to use water softening equipment on
domestic water systems to reduce the scaling potential and
lengthen equipment life. In extreme water conditions, it may
be necessary to avoid the use of the HWG option since the
potential cost of frequent maintenance may offset or exceed
any savings. Consult Table 1 for scaling potential tests.
⚠ WARNING! ⚠
WARNING! A 150°F setpoint may lead to scalding or
burns. The 150°F setpoint must only be used on systems
that employ an approved anti-scald valve.
Figure 4: HWG Double Tank Installation
Hot Outlet
to House
Cold Inlet from
Domestic supply
Hot Outlet to
house
Cold Inlet from
Domestic supply
Shut-off
Valve #1
Upper
element to
120 - 130°F
[49 - 54°C]
Shut-off
Valve #3
Out
In
Shut Off
Valve #2
Powered
Water
Heater
Cold Inlet
Hot Outlet
Shut-off
Valve #4
Shut-off
Valve #1
Lower
element to
100 - 110°F
[38 - 43°C]
Upper element to 130°F [54°C]
(or owner preference)
Shut-off
Valve #4
Powered
Shut-off
Valve #3
Out
In
Insulated water lines 5/8” OD, 50 ft maximum (one way) meters
[16mm OD, 15 meters maximum]
Unpowered
Water Heater
Lower element to 120°F [49°C]
Water Heater
Shut Off
Valve #2
Field Supplied 3/4” brass nipple and “T”
Insulated water lines - 5/8” OD, 50 ft maximum (one way)
[16mm OD, 15 meters maximum]
Installation, Operation, Maintenance
15
Installation, Operation & Maintenance - HNW Water to Water Series
Hot Water Generator, Cont'd.
INSTALLATION
The HWG is controlled by two sensors and the DXM2.5
microprocessor control. One sensor is located on the
compressor discharge line to sense the discharge
refrigerant temperature. The other sensor is located on the
HWG heat exchanger’s “Water In” line to sense the potable
water temperature.
⚠ WARNING! ⚠
Figure 5: Anti-Scald Valve Piping Connections
ANTI-SCALD
VALVE PIPING
CONNECTIONS
ANTI-SCALD
VALVE
C
HOT WATER
TO HOUSE
M
H
When the control is powered and the HWG pump output is
active for water temperature sampling or HWG operation,
the DXM2.5 status LED will slowly flash (On 1 second, Off
1 second).
If the control has detected a HWG fault, the DXM2.5 status
LED will flash a numeric fault code as follows:
High Water Temperature (> 160ºF)
Hot Water Sensor Fault
Compressor Discharge Sensor Fault
5 flashes
6 flashes
6 flashes
Fault code flashes have a duration of 0.3 seconds with
a 10 second pause between fault codes. For example, a
“Compressor Discharge Sensor Fault” will be six flashes 0.3
seconds long, then a 10 second pause, then six flashes again,
etc.
⚠ WARNING! ⚠
WATER HEATER
Hot Water Generator settings are determined by DIP
switches 3-2, 3-3, and 3-4.
DIP 3-2 controls the HWG Test Mode. It provides for forced
operation of the HWG output, activating the HWG pump for
up to five minutes.
ON = HWG test mode, OFF = normal HWG operation.
The control will revert to standard operation after five
minutes regardless of switch position.
DIP 3-3 determines HWG setpoint temperature. It provides
for selection of the HWG operating setpoint.
ON = 150°F (66°C), OFF = 125°F (52°C).
DIP 3-4 is for the HWG status. It provides HWG operation
control.
P4
C
Gnd B-
(240Vac)
(240Vac)
N.O.
Com
Fan Enable
Units are shippedY2Wfrom the factory with this
switchFaninSpeed
the
O
OFF position.
G
R
P8
Test
C
Figure 6: Hot Water
Generator Settings
AL1
12V
IN
OUT
Gnd
NC
P12
P2
AL2
R
NSB
C
Alarm
Relay
Micro
U1
JW1
7"
1
Fault Status
ESD
OVR
H
A
Off
On
1 2 3 4
P3
S3
Off
Off
On
1 2 3 4 5 6 7 8
R
NO1
NC1
COM1
NO2
NC2
R
COH
COM
Installation, Operation, Maintenance
Acc1
Relay
Acc2
Relay
S1
P11
AO2 Gnd
On
1 2 3 4 5 6 7 8
Hot Water
Generator
Settings
COM2
16
A+ 24V
P1enabled, OFF = HWG mode disabled.
N.C.
ON = HWG modeY1
N.O.
R
P5
Factory Use
WARNING! Using 150°F setpoint on the HWG will result
in water temperatures sufficient to cause severe physical
injury in the form of scalding or burns, even when the hot
water tank temperature setting is visibly set below 150°F.
The 150°F HWG setpoint must only be used on systems
that employ an approved anti-scald valve (part number
(AVAS4) at the hot water storage tank with such valve
properly set to control water temperatures distributed to
all hot water outlets at a temperature level that prevents
scalding or burns.
8” MAX
WARNING! Under no circumstances should the sensors
be disconnected or removed. Full load conditions can drive
hot water tank temperatures far above safe temperature
levels if sensors are disconnected or removed.
The DXM2.5 microprocessor control monitors the refrigerant
and water temperatures to determine when to operate
the HWG. The HWG will operate any time the refrigerant
temperature is sufficiently above the water temperature.
Once the HWG has satisfied the water heating demand
during a heat pump run cycle, the controller will cycle the
pump at regular Intervals to determine if an additional HWG
cycle can be utilized.
COLD WATER
SUPPLY
CHECK VALVE
S2
A0-1 A0-2
JW3
CCH
Relay
RV
Relay
HP
HP
LP
LP
LT1
LT1
LT2
LT2
RV
RV
CO
12 CO
P7
1 24Vdc
EH1
4 EH2
Comp
Relay
P10
T1 T2 T2 T3 T3 T4 T4
P9
T5 T5 T6 T6
P6
CCG
CC
Installation, Operation & Maintenance - HNW Water to Water Series
Hot Water Generator, Cont'd.
⚠ WARNING! ⚠
WARNING! The HWG pump is fully wired from the
factory. Use extreme caution when working around
the microprocessor control as it contains line voltage
connections that presents a shock hazard that can cause
severe injury or death.
The heat pump, water piping, pump, and hot water tank
should be located where the ambient temperature does
not fall below 50°F [10°C]. Keep water piping lengths at a
minimum. DO NOT use a one way length greater than 50 ft.
(one way) [15 m]. See Table 2 for recommended piping sizes
and maximum lengths.
All installations must be in accordance with local codes. The
installer is responsible for knowing the local requirements,
and for performing the installation accordingly. DO NOT
activate the HWG (turn DIP 3-4 to the ON position) until
“Initial Start-Up” section, below is completed. Powering the
pump before all installation steps are completed will damage
the pump.
WATER TANK PREPARATION
1. Turn off power or fuel supply to the hot water tank.
2. Connect a hose to the drain valve on the water tank.
3. Shut off the cold water supply to the water tank.
4. Open the drain valve and open the pressure relief valve
or a hot water faucet to drain tank.
5. When using an existing tank, it should be flushed with
cold water after it is drained until the water leaving the
drain hose is clear and free of sediment.
6. Close all valves and remove the drain hose.
7. Install HWG water piping.
HWG WATER PIPING
1. Using at least 1/2” [12.7 mm] I.D. copper, route and install
the water piping and valves as shown in Figures 21 or
22. Install an approved anti-scald valve if the 150°F HWG
setpoint is or will be selected. An appropriate method
must be employed to purge air from the HWG piping.
This may be accomplished by flushing water through the
HWG (as in Figures 21 and 22) or by installing an air vent
at the high point of the HWG piping system.
2. Insulate all HWG water piping with no less than 3/8
inches [10 mm] wall closed cell insulation.
3. Open both shut off valves and make sure the tank drain
valve is closed.
WATER TANK REFILL
1. Close valve #4. Ensure that the HWG valves (valves #2
and #3) are open. Open the cold water supply (valve #1)
to fill the tank through the HWG piping. This will force
water flow through the HWG and purge air from the
HWG piping.
2. Open a hot water faucet to vent air from the system until
water flows from faucet; turn off faucet. Open valve #4.
3. Depress the hot water tank pressure relief valve handle
4.
5.
6.
to ensure that there is no air remaining in the tank.
Inspect all work for leaks.
Before restoring power or fuel supply to the water
heater, adjust the temperature setting on the tank
thermostat(s) to insure maximum utilization of the heat
available from the refrigeration system and conserve
the most energy. On tanks with both upper and lower
elements and thermostats, the lower element should
be turned down to 100°F [38°C] or the lowest setting;
the upper element should be adjusted to 120-130°F
[49-54°C]. Depending upon the specific needs of the
customer, you may want to adjust the upper element
differently. On tanks with a single thermostat, a preheat
tank should be used (Figure 4).
Replace access cover(s) and restore power or fuel supply.
INITIAL START-UP
1. Make sure all valves in the HWG water circuit
are fully open.
2. Turn on the heat pump and allow it to run for
10-15 minutes.
3. Set S3-4 to the “ON” position (enabled) to engage
the HWG. See Figure 6.
4. The HWG pump should not run if the compressor is
not running.
5. The temperature difference between the water entering
and leaving the HWG coil should be approximately
5-10°F [3-6°C].
6. Allow the unit to operate for 20 to 30 minutes to insure
that it is functioning properly.
Table 2: HWG Water Piping Sizes and Length
Unit
Nominal
Tonnage
Nominal HWG
Flow (gpm)
1/2" Copper
(max length*)
3/4" Copper
(max length*)
2.0
0.8
50
-
2.5
1.0
50
-
3.0
1.2
50
-
3.5
1.4
50
-
4.0
1.6
45
50
5.0
2.0
25
50
6.0
2.4
10
50
*Maximum length is equivalent length (in feet) one way of type L copper.
⚠ CAUTION! ⚠
CAUTION! Use only copper piping for HWG piping due to
the potential of high water temperatures for water that has
been in the HWG heat exchanger during periods of no-flow
conditions (HWG pump not energized). Piping other than
copper may rupture due to high water temperature and
potable water pressure. CPVC, PEX, or other plastic pipe
should not be used HWG piping
Installation, Operation, Maintenance
17
Installation, Operation & Maintenance - HNW Water to Water Series
Electrical – Line Voltage
⚠ CAUTION! ⚠
⚠ WARNING! ⚠
CAUTION! Use only copper conductors for field installed
electrical wiring. Unit terminals are not designed to accept
other types of conductors.
WARNING! Disconnect electrical power source to prevent
injury or death from electrical shock.
GENERAL LINE VOLTAGE WIRING
Be sure the available power is the same voltage and phase
as that shown on the unit serial plate. Line and low voltage
wiring must be done in accordance with local codes or the
National Electric Code, whichever is applicable.
WARNING! To avoid possible injury or death due to
electrical shock, open the power supply disconnect switch
and secure it in an open position during installation.
POWER CONNECTION
Line voltage connection is made by connecting the incoming
line voltage wires to the power distribution block, or
compressor contactor, refer to unit wiring diagram. Consult
the electrical data table (Table 3) for correct fuse size.
TRANSFORMER
The units are factory wired for 230 Volt. If supply voltage is
208V, transformer must be rewired by installer as illustrated
on the wiring diagram by switching the Red (208V) and the
Orange (230V) at the contactor terminal L1.
LOAD AND SOURCE PUMPS
Wire pumps to unit per unit wire diagram.
⚠ WARNING! ⚠
All field installed wiring, including electrical ground, must
comply with the National Electrical Code as well as all
applicable local codes.
Refer to the unit wiring diagrams and electrical data
table (Table 3) for fuse sizes and a schematic of the field
connections which must be made by the installing (or
electrical) contractor.
Consult the unit wiring diagram located on the inside of the
compressor access panel to ensure proper electrical hookup.
All final electrical connections must be made with a length of
flexible conduit to minimize vibration and sound transmission
to the building.
Table 3: HNW Electrical Data
LRA
QTY
HWG
Pump
FLA
16.7
79.0
1
0.5
4.0
21.2
25.3
40
26.3
134.0
1
0.5
4.0
30.8
37.3
60
26.3
134.0
2
0.5
4.0
57.1
63.6
80
Compressor
Model
Voltage
Code
Voltage
Min/Max
Voltage
RLA
036
3
208/230/60/1
197/252
060
3
208/230/60/1
197/252
120
3
208/230/60/1
197/252
HACR circuit breaker in USA only
Residential units come standard with 75VA transformer, and optional HWG pump.
18
Installation, Operation, Maintenance
EXT Loop
Pump
FLA
Total
Unit
FLA
Min
Circuit
Amps
Max
Fuse/
HACR
Installation, Operation & Maintenance - HNW Water to Water Series
Electrical – Low Voltage Wiring
NOTE: Do not close up unit until checkout is completed.
2
The valve will remain open during a unit lockout.
The valve will draw approximately 25-35 VA through
the “Y” signal of the aquastat
Accessory Motorized
Water Valve
Aquastat
Y
FigureUnidad
8: Accessory
Motorized Water Valve Empacada
Typical Wiring Example #2
C
W/Y
C
Y1
2 LED
A-Stat
1
C
Y1
3
Calentador Interruptor
AVM
Taco Válvula
DXM2.5
End Switch
Y
TACO VALVE
C
1.
2.
3
Y1
Heater Switch
C
1
C
WATER SOLENOID VALVES
An external solenoid valve(s) (with end switch so valve is fully
open before compressor starts) should be used. Valve should
also be normally closed type so water flows through only
when unit is operating. A slow closing valve may be required
to help reduce water hammer. Typical wiring for a 24VAC
external solenoid valve. Figures 5 or 6 illustrate typical slow
closing water control valve wiring for Taco zone sentry series
(Heat Controlller P/N AMV…) and Taco SBV series valves. Slow
closing valves take approximately 60 seconds to open (very
little water will flow before 45 seconds). Once fully open, an
end switch closure allows the compressor to be energized.
When wired as shown, the slow closing valve will operate
properly with the following notations:
Unit
Controller
Y1
Figure 7: Accessory Motorized Water Valve Typical Wiring Example #1
C
Unit is typically controlled by field installed and wired
aquastat and mode changeover switch (R to O is cooling
mode). Wire to DXM2.5 P1 terminals, use minimum 18GA
Class II wire.
Termostato
Installation, Operation, Maintenance
19
Installation, Operation & Maintenance - HNW Water to Water Series
Controls – DXM2.5
DXM2.5 CONTROLS
For detailed controller information,
see the DXM2.5 Application,
Operation, and Maintenance (AOM)
manual (part # 97B0142N01).
20
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Unit Commissioning & Operating Limits
ENVIRONMENT
This unit is designed for indoor installation only. Do not install
in an area subject to freezing or where humidity levels can
cause cabinet condensation.
POWER SUPPLY
A voltage variation of +/- 10% of nameplate utilization
voltage is acceptable.
Operation and performance is primarily dependent upon
water temperatures, water flow rates and ambient air
temperature. This water-to-water heat pump is capable
of operating over a wide temperature range and with flow
rates of between 1.5 GPM (.1 l/s) and 3 GPM (.19 l/s) per ton,
however usually no more than one of these factors may be at
a minimum or maximum level at a time.
THE COMMISSIONING TABLE indicates water temperatures
which are suitable for initial unit commissioning in an
environment where the flow rate and water temperature is
not yet stable and to avoid nuisance shut down of the units
freeze and refrigerant pressure safeties.
Table 4
BUILDING COMMISSIONING
Cooling
Unit Size
Source
Min/Max
Load
Min/Max
Ambient
Min/Max
036
Heating
060/120
50/80°F
50/80°F
10/27°C
10/27°C
60/80°F
60/90°F
16/27°C
16/32°C
45/110°F
7/43°C
036
060/120
50/80°F
50/80°F
10/27°C
10/27°C
60/120°F
60/120°F
16/49°C
16/49°C
39/85°F
4/29°C
BUILDING OPERATING
COOLING
Unit Size
Source
Min/Max
Load
Min/Max
Ambient
Min/Max
036
060/120
50/80°F
50/80°F
10/27°C
10/27°C
60/80°F
60/90°F
16/27°C
16/32°C
45/110°F
7/43°C
HEATING
036
060/120
50/80°F
50/80°F
10/27°C
10/27°C
60/120°F
60/120°F
16/49°C
16/49°C
39/85°F
4/29°C
THE OPERATING TABLE indicates the maximum and
minimum ranges of the unit.
For more specific unit performance, reference the product
catalog, the submittal data sheets or contact your supplier
for assistance.
Installation, Operation, Maintenance
21
Installation, Operation & Maintenance - HNW Water to Water Series
Unit & System Checkout
⚠ WARNING! ⚠
WARNING! Verify ALL water controls are open and allow
water flow prior to engaging the compressor. Freezing
of the heat exchanger or water lines can permanently
damage the heat pump.
NOTE: The manufacturer strongly recommends all piping
connections, both internal and external to the unit, be
pressure tested by an appropriate method prior to any
finishing of the interior space or before access to all
connections is limited. Test pressure may not exceed
the maximum allowable pressure for the unit and all
components within the water system. The manufacturer
will not be responsible or liable for damages from water
leaks due to inadequate or lack of a pressurized leak test,
or damages caused by exceeding the maximum pressure
rating during installation.
BEFORE POWERING SYSTEM, please check the following:
UNIT CHECKOUT
 Balancing/Shutoff Valves: Ensure all isolation valves are
open, water control valves wired and open, and flow
switch (load and source) are operational or brazed plates
may burst.
 Line Voltage and Wiring: Ensure Voltage is within
an acceptable range for the unit and wiring and
fuses/breakers are properly sized. Low voltage
wiring is complete.
 Unit Control Transformer: Ensure transformer has
properly selected control voltage tap. 208-230V
units are factory wired for 230 operation unless
specified otherwise.
 Entering Water: Ensure entering water temperatures are
within operating limits of Table 4.
 Low Water Temperature Cutout: Verify low water
temperature cut-out on DXM2.5 is properly set.
 Water Flow Balancing: Verify inlet and outlet water
temperatures on both load and source are recorded for
each heat pump upon startup. This check can eliminate
nuisance trip outs and high velocity water flows that can
erode heat exchangers.
 Unit Controls: Verify DXM2.5 settings are proper and
complete.
22
SYSTEM CHECKOUT
 System Water Temperature: Check load and source
water temperature for proper range and also verify
heating and cooling setpoints for proper operation.
 System pH: Load water pH is 6 - 8.5. Proper pH
promotes longevity of hoses and fittings.
 System Flushing: Verify all hoses are connected end
to end when flushing to ensure debris bypasses unit
heat exchanger and water valves etc. Water used in the
system must be potable quality initially and clean of dirt,
piping slag, and strong chemical cleaning agents. Verify
all air is purged from the system. Air in the system can
cause poor operation or system corrosion.
 Cooling Tower/Boiler: Check equipment for proper
setpoints and operation.
 Standby Pumps: Verify the standby pump is properly
installed and in operating condition.
 System Controls: Verify system controls function and
operate in the proper sequence.
 Low Water Temperature Cutout: Verify low water
temperature cut-out controls are provided for the
outdoor portion of the loop or operating problems
will occur.
 System Control Center: Verify control center and alarm
panel for proper setpoints and operation.
 Units with HWG: Confirm hot water tank(s) and piping
have been filled and air has been purged. HWG is
de-engerized (DIP Switch 12 is "On") unit start up.
 Miscellaneous: Note any questionable aspects of
the installation.
⚠ WARNING! ⚠
WARNING! To avoid equipment damage, DO NOT leave
system filled in a building without heat during the winter
unless antifreeze is added to system water. Condenser
coils never fully drain by themselves and will freeze unless
winterized with antifreeze.
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Unit Start Up Procedure
⚠ WARNING! ⚠
Table 6: Water Pressure Drop HNW036-120
Model
WARNING! When the disconnect switch is closed, high
voltage is present in some areas of the electrical panel.
Exercise caution when working with energized equipment.
1.
2.
3.
4.
Adjust all valves to their full open position. Turn on the
line power to all heat pump units.
Source and Load water temperatures should be within
the minimum-maximum ranges of Table 4.
It is recommended that water-to-water units be first
started in the heating mode, when possible. This will
allow liquid refrigerant to flow through the filter-drier
before entering the TXV, allowing the filter-drier to catch
any debris that might be in the system before it reaches
the TXV.
Four factors determine the operating limits of water
source heat pumps, (a) source entering water
temperature, (b) source entering water flow rate, (c)
load entering water temperature, and (d) load entering
water flow rate. When any one of these factors is at a
minimum or maximum level, the other factors must be at
normal levels to ensure proper unit operation.
a. Place the mode switch (if applicable) in the
"HEAT" position. Adjust the unit aquastat to the
lowest setting.
b. Slowly raise the aquastat setting to a higher
temperature until the compressor activates.
c. Check for warm load water delivery within a few
minutes after the unit has begun to operate.
d. Verify correct water flow by comparing unit
pressure drop across the heat exchanger versus
the data in Table 6. Refer to Table 5. Check the
temperature of both entering and leaving source
water. If the temperature drop is within P1
range,
proceed with the test. If the temperatureY1drop is
outside of the operating range, check refrigerant
Y2
pressures and compare to Tables 7 and 8. Heat of
W
extraction (HE) can be calculated for the source and
O
compared to submittal data capacity pages. The
G
formula for HE for systems with water is as follows:
HE = TD x GPM x 500,
R
C
50°F
SOURCE/OUTDOOR COAX HX
4.5
1.3
036
6.8
3.4
9.0
6.0
7.5
1.3
060
11.3
3.4
15.0
6.2
15.0
1.4
120
22.5
3.8
30.0
6.8
LOAD/INDOOR COAX HX
4.5
0.6
036
6.8
1.4
9.0
2.6
7.5
1.4
060
11.3
3.5
15.0
6.2
15.0
1.6
120
22.5
3.8
30.0
6.8
R
Water Flow, gpm [l/m]
For Open Loop: Ground Water
Systems at 1.5 gpm per ton [
2.0 l/m per kW]
Rise, Cooling
°F, [°C]
7"
20 - 26
[11.1 - 14.4]
Alarm
Relay
Drop,
ESD Heating
°F, [°C]
OVR
70°F
90°F
1.0
2.8
5.1
1.1
3.0
5.5
1.2
3.3
6.1
0.8
2.4
4.5
0.9
2.7
5.0
0.9
2.7
5.0
0.5
1.3
2.4
1.3
3.2
5.8
1.4
3.5
6.4
0.3
1.1
2.2
1.2
3.0
5.5
1.3
3.3
6.0
Must use antifreeze if operation falls in grey area
Multiply PSI x 2.31 to determine ft of hd
NOTE: Units have a five minute time delay in the control
circuit that can be eliminated on the DXM2.5 PCB as shown
in Figure 9. See controls description for detailed features of
the control.
5"
Figure 9: Test Mode Button
C
Gnd B-
A+ 24V
P4
P5
R
(240Vac)
(240Vac)
N.C.
N.O.
Com
N.O.
Fan Enable
Push test button to
enter Test Mode and
speed-up timing and
delays for 20 minutes.
where TD is the temperature differenceAL1
between the
entering and leaving source water, and GPM is the
P2
flow rate in U.S. GPM, determined by comparing
the
pressure drop across the heat exchanger
AL2to Table 6.
Table 5: Water Temperature Change Through NSB
Source Heat Exchanger
C
GPM
e.
JW1
Test
Fan Speed
P8
1
P12
12V
IN
OUT
Gnd
NC
Heating capacity, also known as heat of rejection
Micro
(HR), can be calculated
and compared to submittal
1 HP
U1
data capacity pages. The formula for HR for systems
HP
LP
with
Fault water
Statusis as follows:
LP
LT1
LT1
H 10 - 17
where TD is the temperature difference between
LT2
Off the
On entering and leaving load water, and GPM is the
A[5.6 - 9.4]
LT2
flow rate in U.S. Off
GPM,
determined by comparing
RVthe
On
RV 6.
pressure drop across the heat exchanger to Table
CO
JW3water leaks.
f. S3
Check
for
vibration,
noise,
and
12 CO
Off On
P3
RV
P7
R
Relay
CCH
1 24Vdc
I n sNO1
tallation, Operation, Maintenance
Relay
NC1
S2
Acc1
EH1
Relay
COM
A0-1 A0-2
4 EH2
NO2
S1
HR = TD X GPM X 500,
6 1/2"
Facto
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
1 2 3 4
Factory lo
voltage Mo
connection
unit harnes
23
Factory low
voltage Mole
connection fo
electric heat
harness
Installation, Operation & Maintenance - HNW Water to Water Series
Unit Start Up Procedure, Cont'd.
⚠ WARNING! ⚠
WARNING! Verify ALL water controls are open and allow
water flow prior to engaging the compressor. Freezing
of the heat exchanger or water lines can permanently
damage the heat pump.
5.
Allow five (5) minutes between tests for pressure to
equalize before beginning cooling test.
a. Place the mode switch (if applicable) in the
"COOL" position. Adjust the unit aquastat to the
highest setting.
b. Slowly lower the aquastat setting to a lower
temperature until the compressor activates.
c. Check for cool load water delivery within a few
minutes after the unit has begun to operate.
d. Verify correct water flow by comparing unit
pressure drop across the heat exchanger versus
the data in Table 6. Refer to Table 5. Check the
temperature of both entering and leaving source
water. If the temperature rise is within range,
proceed with the test. If the temperature rise is
outside of the operating range, check refrigerant
pressures and compare Tables 7 and 8. Heat of
rejection (HR) can be calculated for the source and
compared to submittal data capacity pages. The
formula for HR for systems with water is as follows:
HR = TD X GPM X 500,
e.
where TD is the temperature difference between the
entering and leaving source water, and GPM is the
flow rate in U.S. GPM, determined by comparing the
pressure drop across the heat exchanger to Table 6.
Cooling capacity, also known as heat of extraction
(HE), can be calculated and compared to submittal
data capacity pages. The formula for HE for systems
with water is as follows:
HE = TD X GPM X 500,
6.
7.
8.
24
where TD is the temperature difference between
the entering and leaving load water, and GPM is the
flow rate in U.S. GPM, determined by comparing the
pressure drop across the heat exchanger to Table 6.
f. Check for vibration, noise, and water leaks.
If unit fails to operate, perform troubleshooting analysis
(see troubleshooting section). If the check described fails
to reveal the problem and the unit still does not operate,
contact a trained service technician to ensure proper
diagnosis and repair of the equipment.
When testing is complete, set system to maintain
desired comfort level.
BE CERTAIN TO FILL OUT AND RETURN ALL
WARRANTY REGISTRATION PAPERWORK.
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Operating Pressures
Table 7
036-120 (120 Per Circuit) (60 Hz I-P Units)
Source
Entering
Water
Temp °F
Source
Water
Flow
GPM/ton
1.5
50
2.3
3.0
1.5
80
2.3
3.0
Cooling
Load EWT °F
@ 1.5-3.0
GPM/ton
Suction
Pressure
PSIG
Discharge
Water Temp Water Temp
Superheat Subcooling
Pressure
Rise °F
Drop °F
°F
°F
PSIG
Source
Load
50
99-106
230-234
11-18
18-25
60
111-122
241-243
11-18
18-25
70
122-137
251-253
17-25
18-25
80
126-145
254-258
26-35
18-25
9-20
50
98-105
212-214
18-23
14-20
7-15
60
106-117
218-220
18-23
14-20
70
114-129
225-227
24-32
14-20
80
117-135
228-230
32-41
14-20
9-20
50
87-101
199-203
12-18
12-18
8-16
60
91-113
203-207
12-18
12-18
70
95-124
204-216
16-34
12-18
80
107-128
212-217
33-35
12-18
9-20
50
104-111
343-348
9-14
18-25
7-14
60
121-132
355-360
9-14
18-25
70
138-152
367-373
9-14
18-25
80
148-161
377-381
12-23
18-25
9-20
50
103-111
320-325
8-14
14-21
7-14
60
118.-129
328-334
8-14
14-21
70
132-147
336-344
12-20
14-21
80
140-172
343-353
19-29
14-21
9-20
50
94-110
305-314
9-13
12-18
7-15
60
112-121
313-319
9-13
12-18
70
121-146
317-329
12-20
12-18
80
131-151
324-333
18-27
12-18
7-15
20-28
13-18
9-12
19-28
13-18
8-12
Installation, Operation, Maintenance
8-17
8-19
8-17
9-19
8-17
9-19
7-16
8-18
8-16
8-18
8-16
9-18
9-20
25
Installation, Operation & Maintenance - HNW Water to Water Series
Operating Pressures, Cont'd.
Table 8
036-120 (120 Per Circuit) (60 Hz I-P Units)
Source
Entering
Water
Temp °F
Source
Water
Flow
GPM/ton
1.5
50
2.3
3.0
1.5
80
2.3
3.0
26
Heating
Load EWT °F
@ 1.5-3.0
GPM/ton
Suction
Pressure
PSIG
Discharge
Water Temp Water Temp
Superheat Subcooling
Pressure
Drop °F
Rise °F
°F
°F
PSIG
Source
Load
60
85-95
212-224
6-11
7-11
80
91-99
290-310
6-11
7-11
90
92-101
326-338
6-11
7-11
100
96-103
381-399
6-11
7-11
5-17
120
100-108
474-488
6-11
7-11
4-16
60
95-102
215-228
6-13
7-11
7-18
80
98-106
299-313
6-13
7-11
6-18
6-17
6-17
9-16
90
99-108
329-341
6-13
7-11
100
102-110
384-401
6-13
7-11
6-17
120
106-114
475-491
6-13
7-11
5-17
60
95-107
215-256
6-14
7-15
7-19
80
101-110
310-326
6-14
7-15
90
103-112
329-376
6-14
7-15
100
105-114
399-414
6-14
7-15
6-18
120
108-118
476-524
6-14
7-15
5-17
60
109-129
225-237
14-26
5-14
8-18
80
123-138
314-327
14-26
5-14
90
130-142
343-357
10-15
5-14
100
137-147
402-415
10-15
5-14
7-19
120
150-157
493-504
10-15
5-14
6-20
60
111-132
227-239
14-38
6-15
8-20
80
135-147
315-330
14-38
6-15
90
143-152
344-360
10-16
6-15
100
145-154
405-418
10-16
6-15
7-20
120
156-163
494-507
10-16
6-15
6-20
60
110-149
227-279
19-44
6-18
9-21
80
135-150
286-332
19-44
6-18
90
145-166
345-408
13-23
6-18
100
148-158
405-420
13-23
6-18
Installation, Operation, Maintenance
6-12
6-17
6-18
7-19
5-9
6-19
8-19
15-21
7-19
8-20
10-15
7-12
8-20
8-21
8-21
8-21
Installation, Operation & Maintenance - HNW Water to Water Series
Preventative Maintenance
LOAD WATER COIL MAINTENANCE
Generally water coil maintenance is not needed for closed
loop systems. However, if the piping is known to have
high dirt or debris content, it is best to establish a periodic
maintenance schedule with the owner so the water coil
can be checked regularly. Dirty installations are typically
the result of deterioration of iron or galvanized piping or
components in the system. Open cooling towers requiring
heavy chemical treatment and mineral buildup through water
use can also contribute to higher maintenance. Should
periodic coil cleaning be necessary, use standard coil
cleaning procedures, which are compatible with both the
heat exchanger material and copper water lines. Generally,
the more water flowing through the unit, the less chance for
scaling. However, flow rates over 3 gpm per ton (3.9 l/m per
kW) can produce water (or debris) velocities that can erode
the heat exchanger wall and ultimately produce leaks.
SOURCE WATER COIL MAINTENANCE
Open loop systems require periodic cleaning to remove
scaling. Use standard cleaning procedures which are
compatible with cupro-nickel and copper.
HOT WATER GENERATOR COILS
See water coil maintenance for load water coil. If the
potable water is hard or not chemically softened, the high
temperatures of the desuperheater will tend to scale even
quicker than the water coil and may need more frequent
inspections. In areas with extremely hard water, a HWG is
not recommended.
COMPRESSORS
Conduct annual amperage checks to ensure amp draw
is no more than 10% greater than that indicated by serial
plate data.
CABINET
Do not allow water to stay in contact with the cabinet for long
periods of time to prevent corrosion of the cabinet sheet
metal. Generally cabinets are set up from the floor a few
inches for prevention. The cabinet can be cleaned using a
mild detergent.
REFRIGERANT SYSTEM
To maintain sealed circuit integrity, do not install service
gauges unless unit operation appears abnormal. Reference
the operating chart for pressure and temperatures. Verify that
air and water flow rates are at proper levels before servicing
the refrigerant circuit.
If the refrigerant circuit is opened for any reason, a new liquid
line filter-drier must be installed.
Installation, Operation, Maintenance
27
Installation, Operation & Maintenance - HNW Water to Water Series
Troubleshooting Form
Water-to-Water (Heating and Cooling)
Troubleshooting Form
Customer:
Loop Type:
Model #:
Startup Date:
Serial #:
Antifreeze Type & %:
Complaint:
REFRIGERANT: HFC-410A
HEATING POSITION
REFRIG FLOW - HEATING
REFRIG FLOW - COOLING
REVERSING
VALVE
10 12
11 13
5
SUCTION
COMPRESSOR
EXPANSION
VALVE
CONDENSER (HTG)
EVAPORATOR (CLG)
9 LT2:
HEATING
LIQUID
LINE
Description
6
CONDENSER (COOLING)
EVAPORATOR (HEATING)
COAX
Load
COOLING POSITION
Heating
7
COAX
FILTER
DRIER
HWG*
Source
9 LT1:
COOLING
1
LIQUID
LINE
3
8
DISCHARGE
* Turn off HWG before
troubleshooting.
2
4
Cooling
Notes
Water Side Analysis
1 Source Water In Temp.
2 Source Water Out Temp.
H Temp. Diff. =
C Temp. Diff. =
3 Source Water In Pressure
4 Source Water Out Pressure
4a Pressure Drop
4b GPM
Heat of Extraction (Absorption) or Heat of Rejection:
Enter HE or HR:
HE or HR (Btuh) =
Flow Rate (GPM) x
Fluid Factor:
500 (Water); 485 (Antifreeze)
Temp. Diff (deg F) x
Fluid Factor
Refrigerant Analysis
5 Suction Temp.
6 Suction Pressure
6a Saturation Temp.
6b Superheat
7 Discharge Temp.
8 Discharge Pressure
8a Saturation Temp.
8b Subcooling
9 Liquid Line Temp
10 Load Water In Temp.
11 Load Water Out Temp.
H Temp. Diff. =
C Temp. Diff. =
12 Load Water In Pressure
13 Load Water Out Pressure
13a Pressure Drop
13b GPM
Voltage
Compress Amps
RP931
28
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Warranty
LIMITED EXPRESS WARRANTY
Congratulations on purchasing your new HVAC equipment. It’s been
designed for long life and reliable service, and is backed by one of the
strongest warranties in the industry. Your unit automatically qualifies
for the warranty coverage listed below, providing you keep your
proof of purchase (receipt) for the equipment and meet the warranty
conditions.
The warranty begins on the date of purchase by the original consumer. The
consumer must retain a receipted bill of sale as proof of warranty period.
Without this proof, the express warranty begins on the date of shipment from
the factory.
LIMITED TEN (10) YEAR EXPRESS WARRANTY
MARS warrants all parts of the HEW/HNW residential geothermal heat
pump including the compressor to be free from defects in workmanship and
materials for normal use and maintenance for ten (10) years from the date of
purchase by the original consumer for the original installation. This Express
Limited Warranty applies only when the system is installed per MARS installation instructions and in accordance with all local, state and national codes
for normal use.
The sole remedy under the Limited Warranty is replacement of the defective
part. If replacement parts are required within the period of this warranty,
MARS replacement parts shall be used; any warranty on the replacement
part(s) shall not affect the applicable original unit warranty. Ready access
to the unit for service is the owner’s responsibility. Labor to diagnose and
replace the defective part is not covered by this Limited Express Warranty. If
for any reason the replacement part/product is no longer available during the
warranty period, MARS shall have the right to allow a credit in the amount of
the current suggested retail price of the part/product instead of providing repair
or replacement.
LIMITED FIVE (5) YEAR LABOR ALLOWANCE
Labor is allowed for warranty service for a period of five (5) years from the
date of purchase when the unit is properly registered and commissioned
according to the start-up procedure specified in the Installation/Operation
Manual, and when the Geothermal Start-Up Certification Form is completed
and submitted to MARS.
EXCEPTIONS
The Limited Express Warranty does not cover normal maintenance—MARS
recommends that regular inspection/maintenance be performed at least once
a season and proof of maintenance be kept. Additionally, labor charges,
transportation charges for replacement parts, replacement of refrigerant
or filters, any other service calls/repairs are not covered by this Limited
Warranty. It also does not cover any portion or component of the system that
is not supplied by MARS, regardless of the cause of failure of such portion or
component.
CONDITIONS FOR WARRANTY COVERAGE
• Unit must be operated according to MARS operating instructions included
with the unit and cannot have been subjected to accident, alteration,
improper repair, neglect or misuse, or an act of God (such as a flood)
• Installation was done by a trained, licensed or otherwise qualified HVAC
dealer/contractor
• Performance cannot be impaired by use of any product not authorized by
MARS, or by any adjustments or adaptations to components
• Serial numbers and/or rating plate have not been altered or removed
• Damage has not been a result of inadequate wiring or voltage conditions,
use during brown-out conditions, or circuit interruptions
• Air flow around any section of the unit has not been restricted
• Unit remains in the original installation
• Unit was not purchased over the internet
REMEDY PROVIDED BY THE LIMITED EXPRESS WARRANTY
LIMITATION OF LIABILITY
1. There are no other express or implied warranties. MARS makes no
warranty of merchantability. We do not warrant that the unit is suitable
for any particular purpose or can be used in buildings or rooms of any
particular size or condition except as specifically provided in this document.
There are no other warranties, express or implied, which extend beyond
the description in this document.
2. All warranties implied by law are limited in duration to the seven-year term
of the parts warranty. Your exclusive remedy is limited to the replacement
of defective parts. We will not be liable for any consequential or
incidental damages caused by any defect in this unit.
3. This warranty gives you specific legal rights and you may also have other
rights which vary from state to state. Some states do not allow limitation
on how long an implied warranty lasts or do not allow the exclusion or
limitation of incidental or consequential damages, so the above limitations
or exclusions may not apply to you.
4. No warranties are made for units sold outside the continental United States
and Canada. Your distributor or final seller may provide a warranty on units
sold outside these areas.
5. MARS will not be liable for damages if our performance regarding warranty
resolution is delayed by events beyond our control including accident,
alteration, abuse, war, government restrictions, strikes, fire, flood, or other
acts of God.
HOW TO OBTAIN WARRANTY SERVICE OR PARTS
If you have a warranty claim, notify your installer promptly. If the installer
does not remedy your claim, write to MARS, 1900 Wellworth Ave., Jackson
MI 49203. Enclose a report of inspection by your installer or service person.
Include model number, serial number, and date of purchase.
Owner responsibilities are set forth in the
instruction manual—read it carefully.
DURATION OF WARRANTY & REGISTRATION
KEEP THIS INFORMATION AS A RECORD OF YOUR PURCHASE
Please visit www.marsdelivers.com
to register your new product
GEOTHERMAL HEAT PUMP
INSTALLATION
Model Number
Installer Name
Serial Number
Phone Number/Contact Information
Date of Purchase
o Component of new HVAC system
Date Installation Completed
o Replacement heat pump only
Remember to retain your bill of sale as proof of warranty period.
HEW-HNW_WARRANTY_11/2020
Installation, Operation, Maintenance
29
Installation, Operation & Maintenance - HNW Water to Water Series
Notes
30
Installation, Operation, Maintenance
Installation, Operation & Maintenance - HNW Water to Water Series
Notes
Installation, Operation, Maintenance
31
Installation, Operation & Maintenance - HNW Water to Water Series
Revision History
Date:
December 15, 2022
Item:
Action:
All
Transitioned from DXM to DXM2.5 unit controls
October 5, 2021
Pages 11-14
Updated Water Quality Requirements
August 21, 2018
Page 4
Added Warning
January 26, 2017
Page 14
Add caution
December 14, 2015
First Published
Due to ongoing product improvements, specifications and dimensions are subject to change and
correction without notice or incurring obligations. Determining the application and suitability for use
of any product is the responsibility of the installer. Additionally, the installer is responsible for verifying
dimensional data on the actual product prior to beginning any installation preparations.
Incentive and rebate programs have precise requirements as to product performance and certification.
All products meet applicable regulations in effect on date of manufacture; however, certifications are
not necessarily granted for the life of a product. Therefore, it is the responsibility of the applicant to
determine whether a specificmodel qualifies for these incentive/rebate programs.
1900 Wellworth Ave., Jackson, MI 49203 • Ph. 517-787-2100 • www.marsdelivers.com
*97B0123N02*
97B0123N02
32
Installation, Operation, Maintenance
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