INSTALLATION AND OPERATING
INSTRUCTION
Model MWH-180
Residential indoor unit,
Manufactured home (mobile home)
WARNING : If the information in this instruction is not followed exactly, a fire or
explosion may result causing property damage, personal injury or death.
- Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or
any other appliance.
- WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Immediately call your gas supplier from a neighbor's phone.
Follow the gas supplier's instructions.
• If you cannot reach your gas supplier, call the fire department.
- Installation and service must be performed by a qualified installer, service agency or the
gas supplier.
INSTALLER : Leave this manual with the appliance.
CONSUMER : Retain this manual for future reference.
INDEX
SPECIFICATIONS ---------------------------------------------------------------------------- 1,2
PERFORMANCE ------------------------------------------------------------------------------ 2
FEATURES ------------------------------------------------------------------------------------- 3
FOR YOUR SAFETY READ BEFORE OPERATING -------------------------------- 4-10
ABOUT HOT WATER ------------------------------------------------------------------------ 11
SCALDS - FIRST AID ------------------------------------------------------------------------ 11
REMOTE CONTROLLER OPERATION ------------------------------------------------ 12,13
USE IN THE LIME-RICH WATER (HARD WATER) AREA ------------------------ 14
CAUTION ---------------------------------------------------------------------------------------- 15
PREVENTION OF FREEZING DAMAGE DURING WINTER SEASON -------- 16,17
FOR YOUR SAFETY READ BEFORE OPERATING -------------------------------- 18
OPERATING INSTRUCTIONS ------------------------------------------------------------ 19
DAILY INSPECTION AND MAINTENANCE ------------------------------------------- 20,21
IN CASE THE UNIT REMAINS UNUSED FOR A LONG TIME ------------------- 21
FAULT MONITOR ----------------------------------------------------------------------------- 22,23
TROUBLE SHOOTING AND SOLUTION ---------------------------------------------- 24
EXPLODED VIEW ---------------------------------------------------------------------------- 25,26
PARTS LIST ------------------------------------------------------------------------------------ 27
INSTALLATION INSTRUCTIONS -------------------------------------------------------- 28-31
DIMENSIONS ---------------------------------------------------------------------------------- 32
TEMPLATE OF L TERMINATION INSTALLATION ---------------------------------- 33
SUGGESTED PIPING-BASIC INSTALLATION --------------------------------------- 34
SUGGESTED PIPING-CIRCULATION SYSTEMS ----------------------------------- 35
VENT PIPE INSTALLATION --------------------------------------------------------------- 36-39
HIGH ALTITUDE ------------------------------------------------------------------------------ 40
VENT PIPE INSTALLATION --------------------------------------------------------------- 41-53
GAS LINE SIZING CHARTS --------------------------------------------------------------- 54
GAS PIPING ------------------------------------------------------------------------------------ 55
WATER PIPING -------------------------------------------------------------------------------- 55
PRESSURE RELIEF VALVE --------------------------------------------------------------- 56
ELECTRICAL CONNECTION ------------------------------------------------------------- 56,57
WIRING DIAGRAM --------------------------------------------------------------------------- 58,59
DIAGNOSTIC POINTS----------------------------------------------------------------------- 60
SCHEMATIC DIAGRAM --------------------------------------------------------------------- 61
WIRING REMOTE CONTROLLER ------------------------------------------------------- 62
MAIN REMOTE CONTROLLER CMR-2250 (P/N 3748) ---------------------------- 63
BATH REMOTE CONTROLLER YST-2250 (P/N 3749) ----------------------------- 64
TESTING OPERATION ---------------------------------------------------------------------- 65
INSTRUCTIONS FOR CONVERSION --------------------------------------------------- 66
WARRANTY ------------------------------------------------------------------------------------ 70
SPECIFICATIONS
Model number
MWH-180
Type of appliance
Gas continuous flow water heater
Approved gas type
Natural or Propane
Installation
Indoor only / Wall hanging
Set point temperature
(without remote)
Factory setting - 120º F
Temperature range with remote
Remote controller : 96 - 140º F
Exhaust system
Direct vent - forced combustion
Dimensions
Height 24 1/32" (610mm)
Width 13 25/32" (350mm)
Depth 8 3/8" (210mm)
Weight
43 lbs.
Connections
Gas 3/4" MNPT
Water inlet 3/4" MNPT
Hot water outlet 3/4" MNPT
Ignition system
Direct electronic ignition
Electrical consumption
Normal 61 watts
Standby Main/Bath remote controller on 3.7 watts
Anti-frost operation 84 watts
Recommended minimum water
supply pressure
15 PSI
(recommended 25-75 psi for maximum performance)
Maximum water supply pressure 150 PSI
Power supply
Appliance AC120V - 60Hz
Remote controller DC12V (digital)
-1-
SPECIFICATIONS
Flame failure - Flame rod
Over heat switch 212º F
Over heat limit 203º F
Safety devices
Thermal fuse 363º F
Automatic frost protection
Fan motor rpm check - PCB
Over current - Fuse (5 amp)
Remote controller (option)
CMR-2250(P/N 3748) Main control kitchen / laundry
YST-2250(P/N 3749)
Bathroom control
Remote controller cable (option) Nonpolarized two core cable
Clearance from combustibles
Top of heater 12" (30.5cm)
Front of heater 6" (15.2cm)
Sides of heater 2" (5.1cm) [6"(15.2cm) for reading of labels]
Back of heater 0" (0cm)
Floor 12" (30.5cm)
Vent pipe 0" (0cm)
PERFORMANCE
Gas consumption
Gas supply pressure
Mainfold gas pressure
MAXIMUM
MINIMUM
Natural Gas
180,000 Btu/h
20,000 Btu/h
Propane Gas
180,000 Btu/h
20,000 Btu/h
Natural Gas
10.5" W.C.
4" W.C.
Propane Gas
14" W.C.
8" W.C.
Natural Gas
2.5" W.C.
0.4" W.C.
Propane Gas
2.5" W.C.
0.4" W.C.
Hot water capacity
0.58-5.8 GPM
Maximum hot water capacity (54º F rise)
5.8 GPM
-2-
FEATURES
The MWH-180 is a new advanced technology water heater. It produces hot water, continuously,
at the preset temperature of 120ºF. For optimal performance, we recommend the use of the
optional remote controllers.
The MWH-180 will never run out of hot water. Hot water is available as long as a hot water faucet
is open.
As soon as a hot water faucet is opened, a signal goes to the microprocessor to start the burner
operation. Closing the faucet sends the shut down signal to stop the burner.
The MWH-180 is furnished with an electronic ignition system.
This feature eliminates gas usage when no hot water is being used, leading to significant savings
in energy and money.
The advanced control system uses a sensor to continuously maintain the outgoing water
temperature.
The safety protections of the microprocessor include limiting the maximum temperature of the hot
water. The maximum temperature of water, without using the remote controllers, is preset at 120ºF.
A fault monitor will display malfunction codes on the remote controllers. This simplifies trouble
shooting during service calls.
The MWH-180 is designed to prevent varying temperature of hot water when the faucet is cycled
on and off. There is also a quick response mode for rapid heating.
The dimensions of the MWH-180 use less wall space and no floor space.
The remote controllers are a crisp, modern design to blend in any decor.
Endless loop in input and output control ensures a stable flow of hot water.
Low NOx. The Rich - Lean design of the burner produces minimum nitrous oxides.
Greater reliability of electric components due to the potted control circuit board.
-3-
FOR YOUR SAFETY READ BEFORE OPERATING
For your safety and proper use of the unit.
Read and understand the following important symbols before use.
The cases shown below are classified by the degree of risk and damage.
Be sure to follow the instruction symbols for your safety.
Danger
"Danger" indicates that serious injuries or even death to the user may result
if the instruction is neglected and the unit is mishandled.
Warning
"Warning" indicates the possibility that serious injuries or even death to the
user may result if the instruction is neglected and the unit is mishandled.
Caution
"Caution" indicates the possibility that some injuries to the user, and/or
material damage may result if the instruction is neglected and the unit is
mishandled.
Each mark indicates:
General instruction
Electric shock
Fire
High temperature
General prohibited
No flammables
Do not touch
Do not disassemble.
Never fail to do.
Ground
-4-
FOR YOUR SAFETY READ BEFORE OPERATING
Danger
Unfastening of the vent pipes can cause a shortage of oxygen, fire, or overheating.
Check
Check to make sure the flue pipe or vent pipe is properly connected.
Leaking exhaust gas indoors poses a danger if the pipes are unfastened during operation.
Blockage in the vent pipes.
Check
Make sure the flue pipe and vent pipe are
clear of any blockage such as bird's nest,
or debris such as leaves, twigs or weeds.
The blockage may cause the leakage of the
exhaust gas indoors during operation,
which is dangerous.
In winter make sure snow does not block
the vent pipe.
Take necessary measures to prevent snow
drifts from blocking the outlet/inlet of the flue
pipe.
Check for gas leak. (May cause fire.)
Close
Close
If a gas leak is noticed, stop using the unit immediately and close the gas valve, then contact
your service person, or the gas supply company.
Do not light any appliance, disconnect/connect the power plug or touch any electric switch.
Close the main gas valve in case the unit is not used for a long time.
No open flame
Prohibited
-5-
FOR YOUR SAFETY READ BEFORE OPERATING
Warning
Caution to prevent scalding.
Caution
Check the water temperature by hand first before using shower or stepping into the bath tub.
Do not change the temperature setting while others are running hot water.
Gush of hot water may cause scalding or cold water may cause discomfort.
Measures to be taken in case of emergency.
When there is an emergency such as earthquakes, tornadoes, hurricanes or fire follow these
procedures.
Turn off
1. Turn off the hot water faucet.
2. Close the gas valve and the main water valve.
3. Turn off the main power.
Warning, in case of gas leakage, first close the gas
valve and wait for the leaked gas to disperse, then
turn off the main power supply.
Close
Close
4. Contact your service technician, or gas supplier.
Confirm type of gas and power supply.
(Wrong gas type may cause incomplete combustion, explosive ignition or fire.)
DIRECT VENT AUTOMATIC INSTANTANEOUS GAS WATER HEATER
FOR INDOOR INSTALLATION
NATURAL GAS / PROPANE GAS
ANSI Z21.10.3-2004
CSA 4.3-2004
CHAUFFE-EAU INSTANTANÉ AUTOMATIQUE À ÉVENT DIRECT POUR
INSTALLATION INTÉRIEUR.
NAT / GPL
MODEL : MWH-180
NATURAL GAS (Gaz Naturel)
PROPANE GAS (GPL)
180,000 Btu/h
180,000 Btu/h
MAX. INPUT
Debit calorifique max.
MIN. INPUT
Debit calorifique min.
20,000 Btu/h
20,000 Btu/h
GAS PRESSURE INLET MAX.
Pression de gaz entrée max.
10.5 inches W.C.
10.5 pounces W.C.
14.0 inches W.C.
14.0 pounces W.C.
GAS PRESSURE INLET MIN.
Pression de gaz entrée min.
4.0 inches W.C.
4.0 pounces W.C.
8.0 inches W.C.
8.0 pounces W.C.
GAS PRESSURE MANIFOLD MAX.
Pression d´admission max.
2.5 inches W.C.
2.5 pounces W.C.
2.5 inches W.C.
2.5 pounces W.C.
GAS PRESSURE MANIFOLD MIN.
Pression d´admission min.
0.4 inches W.C.
0.4 pounces W.C.
0.4 inches W.C.
0.4 pounces W.C.
ONLY FOR USE WITH
NATURAL GAS
REFER TO THE LOCAL GAS AUTHORITY FOR CONFIRMATION ON THE GAS TYPE, IF IN DOUBT.
DO NOT REMOVE THIS LABEL UNTIL THE APPLIANCE HAS BEEN INSTALLED AND TESTED.
Si vous ne savez pas le type de gaz, contactez le fournisseur de gaz ou les autorité locaux.
Enlevez pas cette etiquette jusqu´à l´appareil a été installer et verifie.
20457650
or
ONLY FOR USE WITH
Check
Make sure to use the correct gas type as
well as power supply (voltage/frequency)
as indicated on the RATING LABEL
located on the side, of the cabinet.
Natural Gas or Propane Gas are stated
on the GAS TYPE LABEL.
ELECTRICAL RATING
Regime nominal électrique
AC 120V – 60Hz
MAX. WATER PRESSURE
Pression d’eau max.
150 PSI
Wiring Diagram inside Front Cover
Schéma du câblage derrière le couvercle avant.
Minimum clearances from combustible of non-combustible construction
Dégagements minimaux à assurer entre les parois de l´appareil et les constuctions combustibles ou
incombustibles
Back: 0 inch
Front: 6 inches
Top: 12 inches
Side: 2 inches (6 inches for reading of labels)
0 po arrière
6 po devant d´appareil
12 po dessus
2 po côtés (6 po pour lire l´étiquette)
FOR YOUR SAFETY
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other
appliance.
This water heater is required to have with a pressure relief valve. For safe operation of the water heater
the relief valve must not be removed from its designated point of installation or plugged.
POUR VOTRE SÉCURITÉ
Ne pas entreposer ne utiliser d´essence ne d´autres vapeurs ou liquides inflammables à proximité de cet
appareil ou de tout autre appareil.
Ce chauffe-eau dôit être installer avec un soupape de décharge. Pour assurer le fonctionnement
sécuritaire du chauffe-eau, ne pas retirer ni obturer cette soupape de décharge.
20457664
-6-
PROPANE GAS
REFER TO THE LOCAL GAS AUTHORITY FOR CONFIRMATION ON THE GAS TYPE, IF IN DOUBT.
DO NOT REMOVE THIS LABEL UNTIL THE APPLIANCE HAS BEEN INSTALLED AND TESTED
Si vous ne savez pas le type de gaz, contactez le fournisseur de gaz ou les autorité locaux.
Enlevez pas cette etiquette jusqu´à l´appareil a été installer et verifie.
20457720
FOR YOUR SAFETY READ BEFORE OPERATING
Warning
Pay attention to children. (cause of accident.)
Prohibited
Disassembly, repair or modification of the
unit may cause fire, electric shock or other
accidents.
Do Not Disassemble
Do not allow small children to play in the
bathroom or to play with the remote
controllers.
Do not disassemble or modify the units.
Never fail to ask for professional assistance
from your dealer for installation, removal,
auxiliary installation work, or connection to
solar units.
Caution for flammable items.
(May cause fire or explosion.)
No rubber piping.
(May cause gas leakage or fire.)
Warning
GASOLINE
Do not place any flammable items such as
gasoline, benzene, or spray cans near the
appliance.
Do not use them around the heater or the
exhaust vent terminal.
Take special care.
Do not go out or sleep while leaving the hot
water running.
Prohibited
Rubber pipe should never be used for gas
piping line.
No installation outdoors or in the bathroom.
(May cause fire or electric shock or other
accidents.)
Turn off
Prohibited
Turn off
The unit is for indoor installation use.
Never install outdoors or in the bathroom.
Steam from the shower or bath can cause
corrosion or malfunction.
-7-
FOR YOUR SAFETY READ BEFORE OPERATING
Caution
Be sure to electrically ground the unit.
Do not touch the exhaust vent pipe and
water heater during or immediately after
operation.
T!!
O
H
Ground
Do not touch
Do not use hair spray or spray detergent in
the vicinity.
Do not install in locations where excessive
dust or debris will be in the air.
Prohibited
Prohibited
Spray
Do not wipe remote controller with gasoline,
benzene, or detergents.
Do not turn off the water heater or change
the water temperature while someone is
bathing or washing. That may result in scalds
or burns.
Prohibited
Prohibited
-8-
FOR YOUR SAFETY READ BEFORE OPERATING
Caution
Confirm ignition, combustion and extinction.
Check
Do not allow the remote controller to get wet.
(May cause controller to fail.)
Flame logo indicator
Check
Always check Flame logo indicator for
combustion and that the unit has shut down
by checking the operation lamp on the Main
or Bath remote controller.
Do not install near electric appliances.
Measures to be taken for lightning possibility.
(May cause failure.)
Check
When installed near the TV or radio, it may
cause picture disturbance or sound
disturbance.
Provide adequate space around the unit for
service.
Temporary voltage surge caused by lightning
can damage the electronic parts.
Turn off the main power when you hear
thunder.
Pay attention to applications.
Check
Make sure to have enough room around the
unit to ensure space necessary for
checking and maintenance.
Check
Do not use the unit for other applications than
domestic hot water supply and shower.
Commercial use, see warranty.
-9-
FOR YOUR SAFETY READ BEFORE OPERATING
Caution
Use only genuine factory designated parts,
and accessories.
Instruction in case the unit is used in
lime-rich water (hard water) area.
Check
Check
designated
part
Drain the residual hot water in the unit away.
Otherwise the lime may harden and deposit
in the pipe, causing lower efficiency and
damage to the unit. (refer to page 14)
The MWH-180 is designed primarily for
single family home use.
Prohibited
Check
Notice:
If used in a commercial application, a limited
warranty applies.
Water or hot water left in the unit for a long
time is not suitable for drinking or cooking.
Do not drink or use for cooking.
- 10 -
ABOUT HOT WATER
Hot water heater temperature over 125ºF can cause severe burns instantly or death from scalding.
Children, disabled and elderly are at the highest risk of scalding.
Feel water temperature before bathing or showering.
Warning
HOT!!
BURN
SCALDS - FIRST AID
1. Remove clothing; Remove all wet clothing quickly. Wet clothing retains the heat.
2. Apply cold water for 30 minutes; Immediately submerge the burnt area in cold water for 30
minutes to reduce the heat in the skin, preventing deeper burning.
Never use butter, oils or ointment to cover the burn. They may retain the heat.
3. Keep the scalded person warm; Place a blanket around the person.
4. Seek medical advice; Call your medical advice hotline and describe the scald, follow their
directions.
- 11 -
REMOTE CONTROLLER OPERATION
CMR-2250 (P/N 3748)
(Main remote controller)
This remote controller is intended to be used in the kitchen, laundry room or utility area.
Digital Monitor
Indicates the selected
water temperature.
Error messages flash in
the event of a failure.
ON Indicator
Indicates power is on to
the system.
Flame Logo Indicator
Indicates that a hot water
faucet is open and that
control of the temperature
is taken at another
controller.
ON/OFF Button
Power switch to operate
this control.
UP/DOWN Button
Increase or decrease the
desired water temperature.
PRIORITY Indicator
Indicates this controller
has priority control over
the other controller.
YST-2250 (optional P/N 3749)
(Bath remote controller)
This remote controller is intended for installation in the bathroom.
Flame Logo Indicator
Indicates that a hot water
faucet is open and that
control of the temperature
is taken at another
controller.
PRIORITY Indicator
Indicates this controller
has priority control over
the other controller.
ON Indicator
Indicates power is on to
the system.
ON/OFF Button
Power switch to operate
this control.
Digital Monitor
Indicates the selected
water temperature.
Error messages flash in
the event of a failure.
UP/DOWN Button
Increase or decrease the
desired water temperature.
- 12 -
PRIORITY Button
Priority button to set the
water temperature in
Bath remote controller.
REMOTE CONTROLLER OPERATION
Operation of Main/Bath remote controller.
Please read these instructions carefully before using this appliance.
1. Turn on the ON/OFF button. (refer to page 12.)
2. The temperature display will illuminate at 108ºF.
3. The priority indicator will illuminate.
4. Select hot water temperature by pushing UP/DOWN button (
or
) on the controller.
5. Turn on the hot water faucet. Flame logo indicator will illuminate after a short delay.
This indicator will remain illuminated until the hot water faucet is turned off.
6. The hot water temperature can be altered at any time during the operation by pushing
or
UP/DOWN button (
) located on the controller.
or
PRIORITY control. (change.)
The temperature can only be controlled by the remote controller which has the priority indication.
Priority button is only located on the Bath remote controller.
When the priority switch is turned on, priority control over the water temperature is changed
voluntarily.
Warning
Do not turn off the water heater or change the water temperature while someone is bathing
or washing. That may result in scalds or burns.
• In case of installation of both a Main remote controller and a Bath remote controller with priority
button ON, when pushing priority button on Bath remote controller, the hot water temperature
will read 108ºF.
• In case of installation for Bath remote controller only, when pushing priority button on them,
hot water temperature will read 108ºF.
- 13 -
USE IN THE LIME-RICH WATER (HARD WATER) AREA
Caution
In case the unit is used in the lime-rich water (hard water) area, make sure to flush the
residual hot water away.
Otherwise lime may harden and deposit in the pipes causing low efficiency and damage to
the unit.
How to operate.
Perform the following steps after the hot water is used.
If control switch is not easily accessible :
Partially open the hot water faucet so that there is less than half gallon flow until the cold water
starts to run.
1. Turn the ON-OFF button off.
2. Turn on the hot water faucet.
Turn on
Let the residual hot water completely run out.
3.
Turn off
Turn off the hot water faucet when the cold
water starts to run.
• Contact a qualified MPI service technician to remove lime once a year.
Failure to perform the annual maintenance will cause malfunction or damage to the heat
exchanger.
Damage caused by the lime build up is not covered by the unit's warranty.
If a “LC” code shows in the remote controller, call a technician to flush the system.
- 14 -
CAUTION
The residual water in the unit.
Do not drink or cook with any of the water left in the unit or in the pipe for a long time because the
quality may have deteriorated.
Power failure in winter.
Prevent freezing by following steps “ (2) By running water from any faucet. ” or
“ (3) By removing water in unit as freezing may cause damage to the unit. ” as freezing may
cause material damage to the unit. (refer to page 16,17)
Resetting after power failure.
Note :
When not using the remote controller : Ensure that the hot water faucets are turned off.
The unit will automatically reset after power is restored.
When using remote controller(s) : If the remote controller was turned ON, when power is restored,
the remote controller will be ON, and the unit will automatically reset and deliver hot water on
demand.
If the remote controller has been shut OFF, it will remain OFF. After power is restored, and the
remote controller is turned back ON, the unit will be ready to use at the next demand for hot water.
If an error code appears before the power outage, the unit will remain OFF unit the problem is
resolved.
In case damage is caused by natural disasters such as earthquakes,
tornadoes or hurricanes.
If gas or water leakage is suspected even though there is no apparent damage, shut off the Main
Gas valve, close the water valve, disconnect power supply, and check the extent of the damage.
Contact your local dealer for further assistance.
- 15 -
PREVENTION OF FREEZING DAMAGE DURING WINTER SEASON
Prevention of freezing.
The unit or pipe is likely to be damaged by freezing, not only in the cold latitudes, but also in the
mild-temperature zones in winter season. Pay careful attention to prevent freezing pipes.
(1) Anti-frost heater. (automatic.)
The power supply.
Caution
Make sure electrical power is supplied to the heater.
The anti-frost heater keeps the water supply circuit warm inside the unit.
In extremely cold temperature (10ºF) the anti-frost heater may not be sufficient.
The following step 2. or 3. should be tried to avoid freeze up.
(2) By running water from any faucet.
1. Close the main gas valve.
2. Turn on the hot water faucet.
Turn on
About 1/8" (4mm) thick
Close
Keep water running at about 1/10 gal/min
(400cc/min).
3. Turn off the main power.
Notice :
This helps prevent freezing of the pipes and the valves as well.
Check the flow volume 30 minutes after this procedure as the flow may fluctuate.
- 16 -
PREVENTION OF FREEZING DAMAGE DURING WINTER SEASON
(3) By removing water in unit as freezing may cause damage to the unit.
1. Close the main gas valve.
2. Close the main water supply valve.
Close
Close
3. Turn on the hot water faucet.
4. Remove the drain plug and the water
filter. (drain stopper.)
Turn on
Turn on a shower faucet if any.
5. Turn off the main power.
Notice :
This is the best method for protecting the unit.
Although, freeze prevention is not possible for the pipe and the valve.
When operation is resumed, put the water filter (drain stopper) back on and check if water
runs from the hot water faucet by turning on the main water supply valve.
- 17 -
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING : If you do not follow this instruction exactly, a fire or explosion may result
causing property damage, personal injury or loss of life.
A. This appliance does not have a pilot. It is equipped with an ignition device that automatically
lights the burner. Do not try to light the burner by hand.
B. BEFORE OPERATING : Smell all around the appliance area for gas. Be sure to smell next
to the floor because some gas is heavier than air and will settle on the floor.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electric switch, do not use any phone in your building.
• Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call the fire department.
C. Use only your hand to turn the gas control knob. Never use tools. If the knob will not turn by
hand, do not try to repair it, call a qualified service technician. Force or attempted repair may
result in a fire or an explosion.
D. Do not use this appliance if any part has been under water. Immediately call a qualified
service technician to inspect the appliance and to replace any parts of the control system and
any gas control that has been under water.
- 18 -
OPERATING INSTRUCTIONS
1. Stop! Read the safety information mentioned previously before proceeding.
2. Turn off all electric power to the appliance.
3. This appliance does not have a pilot. It is equipped with a direct ignition device that
automatically lights the burner. Do not try to light the burner by hand.
4. Turn the manual valve (installed on the gas supply line) clockwise
to the full OFF position.
Closed manual valve
("OFF" position)
Open manual valve
("ON" position)
5. Wait (5) minutes to clear out any gas. If you then smell gas, STOP! Follow "B" in the safety
information above on this manual. If you do not smell gas, go to next step.
6. Turn the manual valve (installed on the gas line) counterclockwise
to the full ON position.
7. Turn on all electric power to the appliance.
8. If the appliance will not operate, follow the instructions "TO TURN OFF GAS TO APPLIANCE"
and call your service technician or gas supplier.
TO TURN OFF GAS TO APPLIANCE.
1. Turn off all electric power to the appliance if service is to be performed.
2. Turn the manual valve (installed on the gas supply line) clockwise
- 19 -
to the full OFF position.
DAILY INSPECTION AND MAINTENANCE
Tips for the inspection.
Caution
Carry out the inspection and maintenance after the unit is shut down and cools off.
Turn the gas valve off and disconnect the power supply.
Pay full attention to any sharp edges on metal parts when doing inspection and
maintenance, as they may cause some injuries.
Never disassemble or modify the components.
Contact the service person when the unit does not work properly.
Inspection. (daily.)
Exhaust outlet, air intake and the
surrounding area.
GASOLINE
Make sure nothing obstructs the exhaust
outlet and air intake.
Make sure all clearances are maintained.
Make sure to keep the area surrounding the
unit and the exhaust outlet clear of any
combustibles and hazardous materials.
Gas leakage.
Water leakage.
Check if gas is leaking from the unit and the
Gas pipe.
Gas leakage will cause a strong odor.
Check if water is leaking from the unit or
the inlet or outlet pipes.
- 20 -
DAILY INSPECTION AND MAINTENANCE
Maintenance. (as required.)
Dust.
Cleaning the water filter. (drain stopper.)
Close
Close the main water supply, open a hot
water faucet to relieve any water pressure,
take the water filter (drain stopper) out, and
clean the filter element inside.
Wipe away dust and stains on the outside
surface of the unit with a cloth or a sponge
soaked in neutral detergent.
How to replace a component.
Contact the dealer when you need a component replaced.
Make sure to use only factory authorized part(s) for replacement.
CAUTION : Do not use the unit if it is not operating correctly.
This may result in explosion, gas leakage, or faulty combustion.
Contact the dealer or qualified service person when a repair is required.
Scheduled inspection.
An inspection is necessary for the unit after it has operated for a long period.
The annual inspection of at least once a year is recommended.
IN CASE THE UNIT REMAINS UNUSED FOR A LONG TIME
Remove the water in the unit in accordance with Prevention of freezing “ (3) By removing water
in unit as freezing may cause damage to the unit ”(refer to page 17) in case the unit is not used
for a long time.
- 21 -
FAULT MONITOR
Fault monitor.
The MPI water heater has a self diagnosing function for faults.
When the unit does not operate correctly an error code is displayed on the Main and Bath remote
controllers digital monitor.
The cause of the fault can be determined after checking the fault numbers indicated on the remote
controller digital monitor.
Error Number
of
Code Flashes
000
001
Problem
Remedy
Check power failure.
-
Power recovery detection.
6
During power failure, remote controller
wiring is disconnected.
(Alarm record can be indicated in calling mode.)
(Only applies when using remote controller before
power failure.)
Turn off the hot water faucets and turn
on again.
(Alarm record can be indicated in calling mode.)
111
1
Gas burner fails to ignite.
Check gas supply.
121
3
Loss of combustion.
Check gas supply and pressure.
141
4
Over heat switch activated.
Call service center.
321
5
Outgoing thermistor wire breakage.
Call service center.
331
10
Heat exchanger thermistor wire breakage.
Call service center.
341
11
Air thermistor wire breakage.
Call service center.
611
7
Fan motor failure.
Call service center.
651
9
Water flow control device failure.
Call service center.
721
2
False flame detection.
Call service center.
740
750
-
After power on, nothing operates, but the
error code displays in 1 minute.
Call service center.
740
750
760
8
Communication failure between remote
controllers and PCB.
Turn off power and turn on again.
990
12
Air supply or exhaust blockage failure.
Check that nothing is blocking the air
intake or exhaust.
LC
-
Scale build-up (in heat exchanger) failure.
Call service center.
Flashing design of combustion indicator of PCB
A light on the PCB will flash 1 to 12 consecutive
times depending on the failure type.
A three second delay occurs between each set
of flashes.
Call an authorized service technician for trouble
shooting and repair.
Number of flashes of the combustion indicator
1 to 12 Flashes
1sec
- 22 -
Off
3sec
FAULT MONITOR
Alarm record monitor mode
Alarm record can be monitored by special operation of remote controller
1. Start up of alarm record calling mode.
While ON/OFF button is OFF, alarm record calling mode is obtained by simultaneously
pushing both UP/DOWN buttons ( and ) at Main or Bath remote controller for 5 consecutive
seconds.
• The ON indicator will flash while alarm record calling mode is ON.
2. Alarm record list indication method.
or
Alarm record can be monitored by pushing UP/DOWN button. (
)
Alarm occurrence order will match the following indication.
1 ---- Previous alarm (If present alarm is not reset, it shows present alarm.)
2 ---- Alarm 2 occurrences ago.
3 ---- Alarm 3 occurrences ago.
4 ---- Alarm 4 occurrences ago.
5 ---- Alarm 5 occurrences ago.
6 ---- Alarm 6 occurrences ago.
7 ---- Alarm 7 occurrences ago.
8 ---- Alarm 8 occurrences ago.
• If no alarm has been input, indicated by hyphen. (---)
3. Clearing alarm record.
During alarm record monitor mode, you can clear alarm record index, alarm record 1-8 and
combustion period during alarm by pushing ON/OFF button for 10 consecutive seconds.
• Clearing of compiled number of alarms shall not be done.
• In case the unit is relocated, be sure to use the above clearing procedure.
4. Completion of alarm record monitor mode.
• Alarm record monitor mode will be completed by simultaneously pushing both UP/DOWN
and
buttons (
) for 5 consecutive seconds.
• Alarm record monitor mode will be disengaged if no further operation is made for 5 consecutive
minutes while alarm record monitor mode is ON.
• Alarm record monitor mode will be disengaged if operation is resumed by other connected
remote controller.
- 23 -
TROUBLE SHOOTING AND SOLUTION
The following problems are not a malfunction or defect.
Check again before asking for servicing.
Problem
Explanation
Hard to ignite at the initial
attempts.
Air in the gas pipe. Shut the hot water supply faucet and
open. Repeat the process.
Hot water does not flow despite
the faucet being open.
Needs minimum water flow to ignite.
Turn the faucet further for more volume.
Hot water supply is discontinued
during the blackout and no
The unit will automatically reset as described on page 15.
recovery after the power is back
on.
Hot water with the desired
temperature is not available at
an instant faucet is turned open.
It takes a little time to reach the set temperature because
of the residual water in the pipe and of the distance
between the unit and the faucet.
White steam comes out from the The exhaust gas contains a lot of vapor which turns white
exhaust outlet.
in contact with cold air.
Hot water looks white.
Air dissolved in the water is separated and appears white.
The blower keeps running for a
while after the hot water faucet
is turned shut.
It continues to run for about 65 seconds to discharge the
exhaust gas in the combustion chamber.
Water temperature and flow
volume sometimes become
unsteady.
Water temperature and flow volume may fluctuate in case
hot water is used at other faucets at the same time or
water pressure changes occur or gas regulator fluctuations.
The surface of the remote
controller feels warm.
The remote controller itself feels warm because of the
display screen light, etc. Electronic circuit is activated even
when the switch of the remote controller is off. The heat is
generated.
Hot water flow volume
Hot water flow volume may fluctuate by the difference in
fluctuates, even in case of same water supply temperature or water is supplied by a well
set temperature.
with pump pressure fluctuations.
Temperature of the water at the
faucet may also vary from the
displayed temperature at the
remote controller.
Hot water temperature may vary from set temperature by
the climate, plumbing length or water flow.
- 24 -
EXPLODED VIEW
51 52
53
50
H
30
54
28
29
22
31
K
19
17
62
A
38
47
21
32
34
55
61
20
3
45
E
6
I
45
1
37
C
25
56
35
37
23
25
L
39
F
7
48
14
24
18
63
36
49
- 25 -
EXPLODED VIEW
4
41
2
40
H
B
L
J
A
E
D
27
F
26
44
15
5
8
46
57
25
K
10
I
9
59
11
J
60
18
43
58
12
40
C
42
16
13
25
57
56
42
- 26 -
D
41
PARTS LIST
Number MPI P/N
Description
Number MPI P/N
Description
1
3701
Front Panel
34
3734
Heat Exchanger Thermistor
2
3702
Casing Assembly
35
3735
Air Inlet Adapter
3
3703
Heat Exchanger Assembly
36
3736
Thermistor Holder
4
3704
Air Inlet Box Assembly
37
3737
Anti-Frost Heater Clip A
5
3705
Gas Connection
38
3738
Thermistor Clip
6
3706
Gas Control Assembly
39
3739
Anti-Frost Heater Clip B
7
3707
Fan Motor Assembly
40
3740
Wall Hanging Bracket
8
3708
Transformer
41
3741
Hexagon Head Screw
9
3709
Water Inlet
42
3742
Quick-Fastener 16A
10
3710
Hot Water Outlet
43
3743
Quick-Fastener 16C
11
3711
Water Filter
44
3744
Rubber Packing
12
3712
Drain Plug
45
3745
Thermal Fuse Clip
13
3713
Water Flow Sensor
46
3746
Igniter Bracket
14
3714
Surge Protector
47
3747
Pressure Tube
15
3715
Cable Inlet
48
3748
Main Remote Controller CMR-2250
16
3716
Water Flow Control Device Assembly
49
3749
Bath Remote Controller YST-2250
17
3717
Igniter Transformer
50
3750
Harness
18
3718
Thermistor
51
3751
Power Supply Lead Wire
19
3719
Over Heat Switch
52
3752
Water Flow Control Device Lead Wire
20
3720
Thermal Fuse
53
3753
Heater Lead Wire
3721-1
PCB (Propane Gas)
54
3754
Terminal Block Lead Wire
3721-2
PCB (Natural Gas)
55
3755
O-ring P4 Fluorine
3722-1
Manifold Assembly (Propane Gas)
56
3756
O-ring P16 EPDM
3722-2
Manifold Assembly (Natural Gas)
57
3757
O-ring P14 EPDM
3723
Burner
58
3758
O-ring P4 EPDM
3724-1
Damper (Propane Gas)
59
3759
O-ring P12 EPDM
3724-2
Damper (Natural Gas)
60
3760
O-ring P8 EPDM
25
3725
Anti-Frost Heater Assembly
61
3761
O-ring P24 NBR
26
3726
Junction Box Cover
62
3762
PCB Fuse
27
3727
Cable Inlet
63
3763
Surge Protector Fuse
28
3728
Electrode Packing
29
3729
Electrode
30
3730
Flame Rod
31
3731
Electrode Holder
32
3732
Frost Sensing Switch
21
22
23
24
- 27 -
INSTALLATION INSTRUCTIONS
• The cases shown below are classified by the degree of risk and damage.
Be sure to follow the instruction for your safety.
Danger
"Danger" indicates that serious injuries or even death may result from the
improper installation due to negligence of following the instructions.
Warning
"Warning" indicates the possibility that serious injuries or even death may
result from the improper installation due to negligence of following the
instructions.
Caution
"Caution" indicates the possibility that some injuries or material damage may
result from the improper installation due to negligence of following the
instructions.
Each mark indicates:
General prohibited
Never fail to do.
Ground
Danger
Never install the unit outdoors as it is exclusively for indoor use.
Do not install it in the bathroom. Electric shock or leakage may result.
To the installers.
Warning
• Read and understand the installation manual to carry out the installation as specified for
proper and safe usage.
• A competent dealer or plumber should perform the complete installation, including
placement venting, plumbing, gas line, and electrical connection.
Consumers should not try to install their own unit.
• Make double sure that the unit runs in accordance with the check items of "trial run"
standard after it is installed. (refer to page 63, Testing operation)
• When installation of water heater and vent pipes, be sure to wear protective equipment
to prevent injuries and burns.
- 28 -
INSTALLATION INSTRUCTIONS
Before installation.
Verification of the unit.
Warning
• Make sure the unit to be installed suits the intended use and application.
• Do not use any gas other than specified on the sticker.
• Do not operate with any power source (voltage/frequency) other than specified on the
sticker.
DIRECT VENT AUTOMATIC INSTANTANEOUS GAS WATER HEATER
FOR INDOOR INSTALLATION
NATURAL GAS / PROPANE GAS
ANSI Z21.10.3-2004
CSA 4.3-2004
ONLY FOR USE WITH
NATURAL GAS
CHAUFFE-EAU INSTANTANÉ AUTOMATIQUE À ÉVENT DIRECT POUR
INSTALLATION INTÉRIEUR.
NAT / GPL
MODEL : MWH-180
NATURAL GAS (Gaz Naturel)
PROPANE GAS (GPL)
MAX. INPUT
Debit calorifique max.
180,000 Btu/h
180,000 Btu/h
MIN. INPUT
Debit calorifique min.
20,000 Btu/h
20,000 Btu/h
GAS PRESSURE INLET MAX.
Pression de gaz entrée max.
10.5 inches W.C.
10.5 pounces W.C.
14.0 inches W.C.
14.0 pounces W.C.
GAS PRESSURE INLET MIN.
Pression de gaz entrée min.
4.0 inches W.C.
4.0 pounces W.C.
8.0 inches W.C.
8.0 pounces W.C.
GAS PRESSURE MANIFOLD MAX.
Pression d´admission max.
2.5 inches W.C.
2.5 pounces W.C.
2.5 inches W.C.
2.5 pounces W.C.
GAS PRESSURE MANIFOLD MIN.
Pression d´admission min.
0.4 inches W.C.
0.4 pounces W.C.
0.4 inches W.C.
0.4 pounces W.C.
REFER TO THE LOCAL GAS AUTHORITY FOR CONFIRMATION ON THE GAS TYPE, IF IN DOUBT.
DO NOT REMOVE THIS LABEL UNTIL THE APPLIANCE HAS BEEN INSTALLED AND TESTED.
Si vous ne savez pas le type de gaz, contactez le fournisseur de gaz ou les autorité locaux.
Enlevez pas cette etiquette jusqu´à l´appareil a été installer et verifie.
20457650
or
ONLY FOR USE WITH
ELECTRICAL RATING
Regime nominal électrique
AC 120V – 60Hz
MAX. WATER PRESSURE
Pression d’eau max.
150 PSI
PROPANE GAS
REFER TO THE LOCAL GAS AUTHORITY FOR CONFIRMATION ON THE GAS TYPE, IF IN DOUBT.
DO NOT REMOVE THIS LABEL UNTIL THE APPLIANCE HAS BEEN INSTALLED AND TESTED
Si vous ne savez pas le type de gaz, contactez le fournisseur de gaz ou les autorité locaux.
Enlevez pas cette etiquette jusqu´à l´appareil a été installer et verifie.
Wiring Diagram inside Front Cover
Schéma du câblage derrière le couvercle avant.
20457720
Minimum clearances from combustible of non-combustible construction
Dégagements minimaux à assurer entre les parois de l´appareil et les constuctions combustibles ou
incombustibles
Back: 0 inch
Front: 6 inches
Top: 12 inches
Side: 2 inches (6 inches for reading of labels)
0 po arrière
6 po devant d´appareil
12 po dessus
2 po côtés (6 po pour lire l´étiquette)
FOR YOUR SAFETY
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other
appliance.
This water heater is required to have with a pressure relief valve. For safe operation of the water heater
the relief valve must not be removed from its designated point of installation or plugged.
POUR VOTRE SÉCURITÉ
Ne pas entreposer ne utiliser d´essence ne d´autres vapeurs ou liquides inflammables à proximité de cet
appareil ou de tout autre appareil.
Ce chauffe-eau dôit être installer avec un soupape de décharge. Pour assurer le fonctionnement
sécuritaire du chauffe-eau, ne pas retirer ni obturer cette soupape de décharge.
20457664
Location of the unit.
Decide where to install the unit by considering customer’s request and venting length
limitations.
Warning
Ventilation
• Install the unit where there is enough space for ventilation.
• Use the designated vent terminal (option).
• Make sure the pipe termination is kept clear of snow.
• In principle, at time of replacing the unit, do not reuse vent pipe, termination, or fitting which
has been used over one year.
However, if the components are made of SUS304 or a material having equal or better
corrosion resistance, they can be reused.
Check for the holes, cracks, blockage, or gap in connections of the piping.
Reuse the components only after making sure there is no problem.
• Do not install the unit where flammables such as gasoline, benzene, and adhesive are
handled.
- 29 -
INSTALLATION INSTRUCTIONS
Installation.
Caution
• Reinforce the wall if necessary as this unit weighs about 43lbs.
• Make sure that there is adequate floor drainage to prevent flooding the floor.
1. Twist 1 screw (for wall hanging) into the wall leaving about 1/8" (4mm) length to hook on.
2. Hook the center hole of the wall hanging bracket onto the screw and securely fix the unit
with 4 screws.
3. Adjust the clearance between the unit and the wall by loosening 8 hexagon head screws
(upper and lower) and then securely fix the unit, so it is level.
Screw
(for wall hanging)
About 1/8"
(4mm)
Wall hanging bracket
24 11/32" (618mm)
Screw
(for wall hanging)
Screw
(for wall hanging)
Screw
(for wall hanging)
Screw
(for wall hanging)
Wall hanging bracket
- 30 -
Hexagon
head screw
INSTALLATION INSTRUCTIONS
Caution
• Check if adjacent wall or ceiling is fire resistant and allows safe distance for fire prevention.
• This water heater is suitable for residential water (potable) heating only. Do not use this
water heater for space heating, combination space heating/domestic water heating, or
commercial water heating applications.
• MWH-180 is not suitable for use in pool or spa applications.
• Maintain proper space around the unit for proper servicing and operation. Minimum
clearances from combustible materials are listed below.
Top of heater
Back of heater
Front of heater
Sides of heater
Floor
Vent pipe
12"
0"
6"
2"
12"
0"
(30.5cm)
(0cm)
(15.2cm)
(5.1cm) [6" (15.2cm) for reading of labels.]
(30.5cm)
(0cm)
• Secure enough space so that the inspection and repairs can be done easily.
• Secure space not only in front but also under the unit.
• Install the vent terminal in a place where sufficient ventilation can be secured.
• This unit is designed to be installed indoors using the proper vent piping to exhaust
by-products of combustion to the outside environment.
Contact your dealer or MPI for proper vent kits.
• Do not install the unit over other combustion appliances such as gas cooking stove or a
range.
Oil residue and dust in the air can adhere to the burner and the heat exchanger resulting in
deformation, loss of efficiency, or damage to electronic components.
• Do not install the vent terminal near the outlets of the other appliances.
Install the air intake terminal away from the wind path as the wind may cause imperfect
combustion.
• Keep the vent terminal away from the wall or the overhangs as far as possible even if it is
noncombustible in order to prevent discoloration and staining caused by the exhaust gas.
• Do not install the unit where commercial chemicals are used.
Those chemicals are ammonia, sulfur, chloride, ethylene compound and acids which are
used at beauty shop, laundry, factory and so forth.
• Do not install the unit over food or dishes.
• Installer must install a Pressure relief valve.
Pipe pressure relief to a drain or outside environment, or within 4" of the floor.
Pipe pressure relief discharge to a drain or outside environment. (refer to page 54)
• The appliance should be located in an area where leakage from the unit or connections will
not result in damage to the area adjacent to the appliance or to lower floors of the
structure. When such locations can not be avoided, it is recommended that a suitable drain
pan, adequately drained, be installed under the appliance. The pan must not restrict
combustion airflow.
- 31 -
24 17/32"
(623mm)
24 1/32"
(610mm)
3 13/16"
(97mm)
3 5/8"
(92mm)
3 13/16"
(97mm)
22 27/32"
(580mm)
2 21/32"
(67mm)
ø
φ5"
ø
(φ127mm)
4 1/16"
(103mm)
8 9/32"
(210mm)
13/32"~1 13/16"
(10~46mm)
DIMENSIONS
13 25/32"
(350mm)
6 5/8"
(168mm)
1 31/32"
(50mm)
1 5/16"
(33.5mm)
4 15/32"
(113.5mm)
- 32 -
4 5/16"
(110mm)
ø 1/8"
φ3
ø
(φ79mm)
TEMPLATE OF L TERMINATION INSTALLATION
Thickness
(refer to TABLE)
Facing plate
Holes
(refer to TABLE)
18 7/16"
(468mm)
L termination
Facing plate
Reducer
6 5/8"
(168mm)
24 17/32"
(623mm)
3 5/16"
(84mm)
1 31/32"
(50mm)
TABLE : Relationship between the range of wall thickness and the diameter of opening on the wall.
Model Number
MPI P/N
the range of wall thickness
the diameter of opening
3810
FFT-7U-200
3.9-9.8"
(100-250mm)
ø5.7-5.9" (ø144-150mm)
3811
FFT-7U-300
9.8-17.7" (250-450mm)
ø5.8-5.9" (ø147-150mm)
3812
FFT-7U-500
17.7-25.6" (450-650mm)
ø6.1-6.9" (ø154-175mm)
3813
(100-250mm)
FFT-7U(L)-200
3.9-9.8"
ø5.7-5.9" (ø144-150mm)
(250-450mm)
3814
FFT-7U(L)-300
9.8-17.7"
ø5.8-5.9" (ø147-150mm)
(450-650mm)
3815
FFT-7U(L)-500
17.7-25.6"
ø6.1-6.9" (ø154-175mm)
*The diameter of the wall opening does not need to be increased if the wall opening is pitched
DOWNWARD towards the outside at a 2º (1/4 in/ft) pitch.
- 33 -
SUGGESTED PIPING-BASIC INSTALLATION
This drawing is intended only as a guide.
It does not imply compliance with local building codes.
Installation must be done in accordance with local building
codes and may vary depending on installation location.
Confer with local building officials before installation.
Union
Union
Union
Shut off valve
Valve 1 Valve 2
Pressure relief valve
Minimum 3/4"
Gas supply
Drain
Valve 3
Valve 4
Minimum 3/4"
Hot water supply line
Minimum 3/4"
Cold water supply line
- 34 -
SUGGESTED PIPING-CIRCULATION SYSTEMS
This drawing is intended only as a guide.
It does not imply compliance with local building codes.
Installation must be done in accordance with local building
codes and may vary depending on installation location.
Confer with local building officials before installation.
Union
Union
Union
Shut off valve
Valve 1 Valve 2
Pressure relief valve
Minimum 3/4"
Gas supply
Drain
Valve 3
Valve 4
Minimum 3/4"
Hot water supply line
Minimum 3/4"
Cold water supply line
Union
Check valve
Hot water return
Storage tank
Pump Check valve
Fixtures
- 35 -
;;
VENT PIPE INSTALLATION
Vent Terminal Clearances.
INSIDE
CORNER DETAIL.
G
v
H
A
D
v
B
E
L
B
C
B
D
FIXEED
CLOS
v
v
F
LE
OPERAB
v
D
FIXEED
S
ABLE CLO
OPER
v
B
I
x
v
B
v
M
J
x
v
K
A
B
v
x
VENT TERMINAL.
AIR SUPPLY INLET.
AREA WHERE TERMINAL IS NOT PERMITTED.
Canadian Installations 1
12 inches (30cm)
US Installations 2
12 inches (30cm)
Clearance to window or door that may
be opened.
6 inches (15cm) for appliances
10,000 Btuh (3kW), 12 inches (30cm)
for appliances 10,000 Btuh (3kW) and
100,000 Btuh (30kW), 36 inches
(91cm) for appliances 100,000 Btuh
(30kW)
6 inches (15cm) for appliances
10,000 Btuh (3kW), 9 inches (23cm) for
appliances 10,000 Btuh (3kW) and
50,000 Btuh (15kW), 12 inches (30cm)
for appliances 50,000 Btuh (15kW)
C=
Clearance to window or door that may
be opened.
*
*
D=
Clearance to permanently closed
window.
*
*
E=
Clearance to unventilated soffit.
*
*
F=
Clearance to outside corner.
*
*
G=
Clearance to inside corner.
*
*
H=
Clearance to each side of center line
extended above meter/regulator
assembly.
3 feet (91cm) within a height 15 feet
above the meter/regulator assembly.
*
I=
Clearance to service regulator vent
outlet.
3 feet (1.83m)
*
J=
Clearance to nonmechanical air supply
inlet to building or the combustion air
inlet to any other appliance.
6 inches (15cm) for appliances 10,000
Btuh (3kW), 12 inches (30cm) for
appliances 10,000 Btuh (3kW) and
100,000 Btuh (30kW), 36 inches (91cm)
for appliances 100,000 Btuh (30kW)
6 inches (15cm) for appliances
10,000 Btuh (3kW), 9 inches (23cm) for
appliances 10,000 Btuh (3kW) and
50,000 Btuh (15kW) 12 inches (30cm)
for appliances 50,000 Btuh (15kW)
K=
Clearance to a mechanical air supply
inlet.
6 feet (1.83m)
3 feet (91cm) above if within 10 feet
(3m) horizontally.
L=
Clearance above paved sidewalk or
paved driveway located on public
property.
7feet (2.13m) 3
*
M=
Clearance under veranda, porch deck,
or balcony.
12 inches (30cm) 4
*
A=
Clearance above grade, veranda,
porch, deck, or balcony.
B=
1
In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code.
In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code.
3
A vent shall not terminate directly above a sidewalk or paved driveway that is located brtween two single family dwellings and
serves both dwellings.
4
Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA-B149.1, one of the following shall be indicated :
a) A minimum clearance value determined by testing in accordance with section 2.20, or ;
b) A reference to the following footnote :
2
Note : Check local codes and ordinances.
When applicable, installation must conform with the Manufactured Home Construction and Safety Standard, Title 24 CFR, Part
3280 or the Canadian Standard CAN/CSA-Z240 MH Mobile Homes, Series M86.
- 36 -
VENT PIPE INSTALLATION
• Use only designated vent terminal (sold separately).
• Install correctly in accordance with the installation manual attached.
• Select the correct switch position depending on the length of the vent pipe.
• Make sure that the proper distance, within the limitations, is determined between the unit and the
termination of the vent pipe.
• Make sure the terminal of the vent pipe sticks out outdoors.
• Prevent the exhaust gas from flowing back indoors through the gap between the termination and
the wall where the vent pipe penetrates.
• Make sure snow drift will not suffocate the vent terminal when it has been piled or fallen.
• Do not place hazardous materials near the end of the vent termination.
• Make sure to install the vent terminal at downward slope to prevent rain from entering inside.
• Some vapor or condensation may be generated from the vent terminal.
• Place the vent terminal where it is not affected by water splashing or falling off the roof eaves.
• A vent system that exits the structure through a sidewall shall terminate not less than 12"
(30.5cm) above the ground.
Check local codes and ordinances which may require higher clearances.
• The termination of the vent system shall not be located in public traffic areas, such as walkways,
unless the vent system is at least 7' (2.1m) above the ground.
• Terminate the system 6' (1.8m) from the combustion air intake of any appliance.
• Place the system at least 3' (0.9m) away from any other building opening, gas utility meter,
service regulator or the like, or less distance if specified in the appliance's instructions.
And also ensure that positioning of the vent system complies with the requirements of
AS5601/AG601 Clause 5.13.6.2/Fig. 5.3
- 37 -
VENT PIPE INSTALLATION
• In case extension of the vent pipe is required, it shall be limited to the maximum of 41' (12.5m)
based on the formula below.
However, the maximum height of the vent pipe is limited to 23 feet.
• Calculate D (distance) value according to the length of the vent pipe and the number of elbows.
D = L + (M90 X 6) + (M45 X 1.5)
D : Distance
L : Total extended length of straight vent pipe and adjustable vent pipe.
M90: Number of 90º elbow
M45: Number of 45º elbow
Note : Maximum number of M90 is 3pcs.
Maximum number of M45 is 5pcs.
In case of combination use for M90 and M45, maximum total number is 5pcs.
To prevent the vent/air intake piping from occurring condensation, the fan has following 4 type
settings with 2 dip swiches, No.7 & No.8 in each D value.
Both dip switch No.7 & No.8 ON is factory setting ; this is suitable for over 30 in D value.
• Depending upon the vent length, dip switch No.7 & No.8 on PCB may need to be adjusted to
compensate fan speed. Read the following instructions to determine which position this switch
should be placed in.
• In case D value is 30 and above, leave dip switch No.7 & No.8 (ON).
• In case D value is 21 and above, but less than 30, set dip switch No.7 OFF and leave dip switch
No.8 (ON).
• In case D value is 15 and above, but less than 21, leave dip switch No.7 (ON) and set dip switch
No.8 OFF.
• In case D value is less than 15, set both dip switch No.7 & No.8 OFF.
(Factory setting No.7 & No.8 ON.)
• Example #2 :
Rain cap
< Dip switch on PCB >
* No.1 dip switch is
ON with Natural
Gas and OFF with
Propane Gas.
Maximum height 23' (7m)
1 2 3 4 5 6 7 8
OFF
Air intake pipe
• Example #1 :
L termination
Reducer
90º elbow
No less than 2º
(1/4 in/ft) upward
< Dip switch on PCB >
< Dip switch on PCB >
1 2 3 4 5 6 7 8
OFF
1 2 3 4 5 6 7 8
OFF
Drain tee
In case of L termination and reducer.
(Refer to Fig. 4-1 page 45)
D = 0' + (0x6) + (0x1.5) = 0
Roof
flashing
In case of 6 straight vents and 2-90º elbows.
(Refer to Fig. 7 right drawing. page 50)
D = 18' + (2x6) + (0x1.5) = 30
- 38 -
VENT PIPE INSTALLATION
Note :
• In case D value is longer than 41, the unit shall be relocated with vent length of less than 41'.
• In case vent pipe requires extension, use coaxial vent pipe and elbows and start from the vent
terminal side.
• Install the vent pipe at slight decline toward the vent terminal. (refer to page 45)
• Install the vent pipe securely by using sling fittings to support the connected parts.
• Use fittings at 5' (1.5m) intervals. Do not use wire.
• When installing extended vent pipe :
Take special precaution to stay clear of combustible surfaces.
• In case of horizontal direct vent installation, be sure to use recommended vent terminal.
• In case of horizontal direct vent installation with recommended vent terminal, connect reducer
between water heater and vent terminal.
• In case of other horizontal direct vent installation, connect reducer between pipe and vent
terminal.
Warning :
• Failure to follow the installation instructions could cause FIRE, CARBON MONOXIDE
POISONING, or DEATH.
• Never change the position of any dip switch other than No.7 & No.8.
• Unauthorized alteration and use of the unit in a wrong setting may cause material damage,
injury accident, scalding, or even death.
• Exceeding the maximum vent length is dangerous and may result in bad combustion.
• Be sure to connect the vent pipes in such a way so that no exhaust gas leaks when they are
installed in a concealed area, such as the attic.
Caution :
• The edges of sheet metal parts may be sharp.
Always wear gloves and appropriate eye, foot, and other protections when handling these
products.
• It is recommended that experienced professionals familiar with the opration and maintenance of
heating appliances and vent / air intake system install this system.
These instructions are a guide to assist a professional installer.
• Before commencing installation, please read the installation instructions carefully.
• Failure to follow the installation instructions could cause not only the lower performance of
appliance but also property damage or personal injury.
• Different manufactures have different joint systems and adhesives.
Do not mix pipe, fitting, or joining methods from different manufacturers.
• Examine all components for shipping damage prior to installation.
- 39 -
HIGH ALTITUDE
• In case of using MWH-180 at elevations 4,500 feet above sea level, configure the settings
each gas type in accordnce with following.
This settings are different to the page 38 and 39.
• In case extension of the vent pipe is required, it shall be limited to the maximum length
Natural Gas - 34ft
Propane Gas - 18ft
• Calculate D (distance) value according to the length of the vent pipe and the number of elbows.
D = L + (M90 X 6) + (M45 X 1.5)
D : Distance
L : Total extended length of straight vent pipe and adjustable vent pipe.
M90 : Number of 90º elbow
M45 : Number of 45º elbow
Note : Maximum number of M90 is 3pcs.
Maximum number of M45 is 5pcs.
In case of combination use for M90 and M45, maximum total number is 5pcs.
In case of Natural Gas model ;
To prevent poor combustion at higher altitudes, the fan has following 3 type settings with 2 dip
switches, No.7 & No.8 in each D value.
Both dip switch No.7 & No.8 ON is factory setting .
• Depending upon the vent length, dip switch No.7 & No.8 on PCB may need to be adjusted to
compensate fan speed. Read the following instructions to determine which position this switch
should be placed in.
• In case D value is 21 and above, leave dip switch No.7 & No.8 (ON).
• In case D value is 12 and above, but less than 21, set dip switch No.7 OFF and leave dip switch
No.8 (ON).
• In case D value is less than 15, leave dip switch No.7 (ON) and set dip switch No.8 OFF.
(Factory setting No.7 & No.8 ON.)
In case of Propane Gas model ;
To prevent poor combustion at higher altitudes, the fan has following 2 type settings with 2 dip
switches, No.7 & No.8 in each D value.
Both dip switch No.7 & No.8 ON is factory setting.
• Depending upon the vent length, dip switch No.7 & No.8 on PCB may need to be adjusted to
compensate fan speed. Read the following instructions to determine which position this switch
should be placed in.
• In case D value is 12 and above, leave dip switch No.7 & No.8 (ON).
• In case D value is less than 12, set dip switch No.7 OFF and leave dip switch No.8 (ON).
(Factory setting No.7 & No.8 ON.)
- 40 -
VENT PIPE INSTALLATION
Note :
• In case D value is longer than 34 for Natural Gas, the unit shall be relocated with vent length
of less than 34'.
• In case D value is longer than 18 for Propane Gas, the unit shall be relocated with vent length
of less than 18'.
• In case vent pipe requires extension, use coaxial vent pipe and elbows and start from the vent
terminal side.
• Install the vent pipe at slight decline toward the vent terminal. (refer to page 45)
• Install the vent pipe securely by using sling fittings to support the connected parts.
• Use fittings at 5' (1.5m) intervals. Do not use wire.
• When installing extended vent pipe :
Take special precaution to stay clear of combustible surfaces.
• In case of horizontal direct vent installation, be sure to use recommended vent terminal.
• In case of horizontal direct vent installation with recommended vent terminal, connect reducer
between water heater and vent terminal.
• In case of other horizontal direct vent installation, connect reducer between pipe and vent
terminal.
• The input rating of this MPI water heater is based on sea level operation.
At higher elevations, the actual input rate may be lower than the value listed on the rating label.
• This water heater is certified for installations from sea-level to 4,500 feet above sea level.
• For installations from 4,500 feet to 7,700 feet, refer to the settings in page 40.
In case of installations for Natural Gas model, reduce Maximum Manifold Gas Pressure at 2.2".
Warning :
• Failure to follow the installation instructions could cause FIRE, CARBON MONOXIDE
POISONING, or DEATH.
• Never change the position of any dip switch other than No.7 & No.8.
• Unauthorized alteration and use of the unit in a wrong setting may cause material damage,
injury accident, scalding, or even death.
• Exceeding the maximum vent length is dangerous and may result in bad combustion.
• Be sure to connect the vent pipes in such a way so that no exhaust gas leaks when they are
installed in a concealed area, such as the attic.
Caution :
• The edges of sheet metal parts may be sharp.
Always wear gloves and appropriate eye, foot, and other protections when handling these
products.
• It is recommended that experienced professionals familiar with the opration and maintenance of
heating appliances and vent / air intake system install this system.
These instructions are a guide to assist a professional installer.
• Before commencing installation, please read the installation instructions carefully.
• Failure to follow the installation instructions could cause not only the lower performance of
appliance but also property damage or personal injury.
• Different manufactures have different joint systems and adhesives.
Do not mix pipe, fitting, or joining methods from different manufacturers.
• Examine all components for shipping damage prior to installation.
- 41 -
VENT PIPE INSTALLATION
General installation requirements.
(1) Selecting installation site.
• A vent system that exits the structure through a sidewall or the like shall terminate not less
than 12" (30.5cm) above the ground.
• The termination of the vent system shall be located above the snow line in geographical
areas where snow accumulates.
• The termination of the vent system shall not be located in public traffic areas, such as
walkways, unless the vent system is at least 7' (2.13m) above the ground.
And also ensure that positioning of the vent system complies with the requirements of
AS5601/AG601 Clause 5.13.6.2/Fig. 5.3
Check local codes and ordinances which may require higher clearances.
(2) Clearance to combustibles and openings
Maintain clearances to openings as follows
• Terminate the system 6' (1.8m) from the combustion air intake of any appliance.
• Place the system at least 3' (0.9m) away from any other building opening, gas utility meter,
service regulator or the like, or less distance if specified in the appliance's instructions.
Items of vent system.
Items shown below in TABLE 1 are used for this vent system. The diameters of pipes are 3.1"
(79mm) for inner vent pipe and 5" (127mm) for outer air intake pipe. The length of the items are
shown in Fig. 1
TABLE 1 : Items
Connection
and
detachment
Fig. 2
(page 42)
Vent length *
Fig. 2
Fig. 2
Fig. 2
Condensation drain
Fig. 4.4
Fig. 2
Vent termination
Fig. 3
(page 43)
Others
Fig. 2,3
Model
Number MPI P/N
Length [300] 11.8"
FFTP300
3801
Length [600] 24.01"
3802
Straight
FFTP600
Length [900] 35.4"
FFTP900
3803
Adjustable Length [175-230] 6.9-9.1" FFTA200
3804
Adjustable
Adjustable Length [215-310] 8.5-12.2" FFTA260
3805
45º elbow
3806
FFTEL45
Elbow
90º elbow
3807
FFTEL90
Male-male Adapter
3808
FFTMM
Drain Tee
3809
Vertical
FFTDP
Refer
to
Straight Termination
FFT7U
TABLE 2
FFT7U(L) (page 46)
Horizontal L Termination
Reducer
3816
FFTRD
Air Intake Pipe
FFTAIP
3817
Vertical
Rain Cap
FFTRT
3818
Support Strap
Support
3819
FFTSTR
(2" clearance)
FFTRFB
Base
3820
FFTRFC
Cap
Roof
Roof Flashing
Members
Adapter A
FFTRFAA 3821
FFTRFAB 3822
Adapter B
* The values enclosed by [ ] are effective length (unit : mm).
Effective length means the length of pipe when it is connected with other pipes.
- 42 -
VENT PIPE INSTALLATION
Straight Length
Adjustable Length
Rain Cap
128
(MPI P/N 3818)
201.5
L
90º elbow (MPI P/N 3807)
45º elbow (MPI P/N 3806)
Male-male Adapter
79
(MPI P/N 3808)
50
153
Air Intake Pipe
55
125
Model Number MPI P/N
L
FFTA200
3804 6.9-9.1" (175-230mm)
FFTA260
3805 8.5-12.2" (215-310mm)
40
Model Number MPI P/N
L
FFTP300
3801
11.8" (300mm)
FFTP600
3802
23.6" (600mm)
FFTP900
3803
35.4" (900mm)
50
505
50
270
L
(MPI P/N 3817)
Drain Tee (MPI P/N 3809)
0.15
70
135
205
50
127
50 40 50
Support Strap
Reducer (MPI P/N 3816)
196
127.6
80
79
190
120.4
470
(MPI P/N 3819)
12
167
112.2
78.8
75
120
133.6
120
L2=305 or 365
L1
79.4
Straight Termination (Refer to TABLE 2 page 46)
FFT-7U
112.2
133.6
L Termination (Refer to TABLE 2 page 46)
FFT-7U(L)
L1 : Refer to TABLE 2 (page 46)
Roof Flashing (adapter)
L1
L1
78.8
L1 : Refer to TABLE 2 (page 46)
Roof Flashing (base)
Roof Flashing (cap)
(MPI P/N 3820)
(MPI P/N 3820)
660
L2
75
278
Model Number MPI P/N
L1
L2
L3
3821 17.3" (440mm) 8.1" (205mm) 25.3" (643mm)
FFTRFAA
3822 17.3" (440mm) 14.5" (369mm) 28.7" (738mm)
FFTRFAB
< Fig. 1 The dimensions of items >
- 43 -
60
L3
20º
40º
128.6
(unit : mm)
VENT PIPE INSTALLATION
A vent system and components are the only vent system and components that have been
approved by CSA to use with this unit.
U.L. Listed vent components of similar dimensions may be used.
All the air used for combustion shall be supplied from the outside and all the exhaust gas shall be
discharged to the outside.
The minimum and maximum wall thickness required for installation:
Minimum 3.9" (10cm)
Maximum 25.6" (65cm)
The procedure of installation.
(1) Common procedure for vertical and horizontal installation.
• Joint connection and detachment method
Items in TABLE 1 shall be connected and detached by one of the following method (a),(b).
The column, Connection and detachment, in TABLE 1, page 40. indicates which method should
be used. Vent pieces should not be cut.
(a) Mainly, method (a) is used for connection and detachment. It’s for Horizontal terminations
(straight termination and L termination), vent lengths, drain tee, and reducer.
Slide piece
Into cover
Stopper bead
Stopper bead
Female end
Male end
Insert the male end fully into the female end until the
stopper bead is seated against the stop end on the
female end.
Then pull out female end, holding the slide piece in, until
the slide piece is clear of the stopper bead.
Confirm female/male ends of the lengths.
A female end has slide piece.
Slide piece
Stopper bead
Female end
Female end
Male end
Male end
Insert the male end fully into the female end until the
stopper bead is seated against the stop end on the
female end.
Pull up the female end with slide piece kept in the
stopper cover.
Connection
Disconnection
< Fig. 2 Joint connection and detachment method (a), (b) >
- 44 -
VENT PIPE INSTALLATION
(b) Rain cap, air intake pipe, and roof flashing (cap) shall be connected by turning the screw at
each end of pipes clockwise as far as they will go, as shown in Fig. 3.
When connecting between air intake pipe and roof flashing (cap), confirm that the end of air
intake pipe reaches the outer bead of roof flashing (cap) because the screw section is hidden
in outer pipe.
When disconnecting them turn counterclockwise.
Rain cap
Female screw
Turn
clockwise
Male screw
Air intake pipe
Female screw
Turn
clockwise
Roof flashing
(cap)
Male screw
Turn clockwise till the end
of air intake pipe reaches
the outer bead of roof
flashing (cap)
< Fig. 3 Joint connection and detachment method (b) >
- 45 -
VENT PIPE INSTALLATION
• Adjustable lengths
Adjustable lengths are available to allow for installation where fixed-length sections do not
produce the desired dimensions. Also adjustable lengths may be used to compensate for
linear thermal expansion/contract between two fixed points.
As shown in Table1, 2 types of adjustable lengths are available according to the limits in which
its effective length can be made longer and shorter.
• Elbows
45º and 90º elbow are available for changing the direction of the vent system.
The flexible section of each can be bent by hand for making small angle adjustment.
Do not bend repeatedly or extremely, because it may cause vent gas leaks.
• Drain tee
Connect the drain tee directly on to the appliance flue outlet as shown in Fig. 4-4, page 45.
Attach one end of a drain hose to the drain tee outlet, and the other end to a condensate drain
so that any steam or condensed water will be handled properly.
The drain hose must be suitable for use with acidic effluent. Follow the appliance manufacturer's
instructions, and all local and national codes for draining the condensate and acidic effluent.
Caution : Periodically check the terminal end to ensure it is not blocked or obstructed.
• Support
Support the vent system every 5' (1.5m).
1) Secure the support to solid material using the screws provided with the support.
2) Loosen the nuts of the cylinder.
After inserting pipes, fasten the loosened nuts.
Use the pairs of nuts and bolts provided with the support.
- 46 -
VENT PIPE INSTALLATION
(2) Detail of installation.
No less than 2º (1/4 in/ft)
No less than 2º (1/4 in/ft)
Male end
L termination
Reducer
Female end
Fig. 4-1
Horizontal installation [FFT-7U(L)]
Fig. 4-3
Horizontal extended installation without drain tee
No less than 2º (1/4 in/ft)
No less than 2º (1/4 in/ft)
Straight termination
Reducer
Male-male adapter
90º elbow
Drain tee
Fig. 4-2
Horizontal installation [FFT-7U]
Fig. 4-4
Horizontal extended installation with drain tee
• Horizontal installation.
Horizontal installation can consist of only horizontal termination (straight termination or
L termination), reducer, and 90º elbow. If the distance between an inner wall and the center of
the appliance flue outlet is under 5.7" (146mm), use L termination [FFT-7U(L)] and reducer as
shown in Fig. 4-1. Otherwise, use straight termination [FFT-7U] and reducer as shown in
Fig. 4-2.
A continuously DOWNWARD slope of no less than 2º (1/4 in/ft) is maintained in the horizontal
portion.
• Horizontal extended installation.
Horizontal extended installation means installation on an internal wall apart from the appliance.
It can consist of straight termination, reducer, straight lengths, adjustable lengths, and elbows
as shown in Fig. 4-3. If vent system has vertically installed lengths longer than 5' (1.5m), or has
3 elbows, install drain tee direct on the appliance flue outlet and male-male adapter before
horizontal lengths as shown in Fig. 4-4. The directions of lengths are different between
Fig. 4-3 and Fig. 4-4.
A continuously DOWNWARD slope of no less than 2º (1/4 in/ft) is maintained in the horizontal
portion toward the outside.
- 47 -
VENT PIPE INSTALLATION
TABLE 2 : Relationship between the range of wall thickness and the diameter of opening on the wall.
Model Number
MPI P/N
the range of wall thickness
the diameter of opening
3810
FFT-7U-200
3.9-9.8"
(100-250mm)
ø5.7-5.9" (ø144-150mm)
3811
FFT-7U-300
9.8-17.7" (250-450mm)
ø5.8-5.9" (ø147-150mm)
(450-650mm)
3812
FFT-7U-500
ø6.1-6.9" (ø154-175mm)
17.7-25.6"
3813
(100-250mm)
FFT-7U(L)-200
ø5.7-5.9" (ø144-150mm)
3.9-9.8"
(250-450mm)
3814
FFT-7U(L)-300
9.8-17.7"
ø5.8-5.9" (ø147-150mm)
3815
FFT-7U(L)-500
17.7-25.6" (450-650mm)
ø6.1-6.9" (ø154-175mm)
*The diameter of the wall opening does not need to be increased if the wall opening is pitched
DOWNWARD towards the outside at a 2º (1/4 in/ft) pitch.
Horizontal installation (See Fig. 5).
The horizontal termination (straight termination and L termination) consists of two parts (sleeve
and termination itself).
Separate them before installation.
1. Check the location of appliance and the path for the vent system.
2. Check wall thickness where the vent system passes through, and select suitable horizontal
termination according to TABLE 2. Cut the opening for the sleeve with the diameter in TABLE 2.
(Cover the flue outlet to avoid debris from entering the appliance)
3. Adjust the length of the sleeve so that the end of the sleeve protrudes about 0.2" (5mm) from
the wall. Then fasten the sleeve with the screw provided.
*Remember a stamped letter on the sleeve.
4. When the opening is too large, twist the packing provided around the end of the sleeve after
peeling off backing paper from the packing.
5. Insert the sleeve to the wall and fasten with 4 screws provided. Use plugs provided if needed.
*Ensure the UP label on sleeve plate is at the top.
*If it isn't easy to insert the sleeve because the packing doesn't fit the wall, press down the
packing during insertion.
6. Seal between the end of the sleeve and wall, and between the end of inner sleeve pipe and
outer pipe.
7. Adjust the length of the termination by fastening it at the stamped number same as that in 2.
8. Fasten the condensation prevention plate with the screw provided.
(In case of L termination or straight termination with reducer and elbow without additional straight
length, this plate must be installed.)
9. Insert the termination into the sleeve from inside wall so that 4 studs on sleeve plate are
inserted into each 4 holes on termination plate and fasten the termination to the sleeve with the
4 nuts provided.
*Ensure that the label on the termination is at the top.
10. Ensure that the end of air intake pipe protrudes about 0.4" (10mm) from the sleeve.
11. If using straight termination, connect reducer on appliance flue outlet, and 90º elbow between
reducer and termination.
If using L termination, connect reducer on appliance flue outlet and slide the adjustable part or
the termination to fit it to the flue outlet.
Make sure that a continuously DOWNWARD slope of no less than 2º (1/4 in/ft) is maintained
in the horizontal portion.
Refer to Fig 4-1 & 4-2 page 45.
12. Attach facing plate for outer wall as required.
*Drill 3 pilot holes in the outer wall first. Then insert plugs to the holes and fasten the facing plate
to the wall with 3 screws provided. Locate the notch of the facing plate at the bottom of the plate.
*Seal between the facing plate and the wall. Do not seal the notch.
- 48 -
VENT PIPE INSTALLATION
3.
10.
Stamped letter
End of air intake pipe
About
0.2"
End of sleeve
Sleeve
Packing
4.
11.
UP
No less than 2º (1/4 in/ft)
L termination
Plug
5.
Reducer
4 Screws
UP
6.
Seal between
sleeve and wall
Horizontal installation [FFT-7U(L)]
Seal between
inner sleeve pipe
and outer pipe
Seal between
sleeve and wall
No less than 2º (1/4 in/ft)
Straight termination
7.
Reducer
90º elbow
Stamped letter
Termination
8.
Condensation prevention
plate
Horizontal installation [FFT-7U]
Screw M4 X 10
9.
UP
12.
3 Plugs
Label
3 Screws
4 Nuts
Facing plate
< Fig. 5 Detail of horizontal installation >
- 49 -
Notch
VENT PIPE INSTALLATION
Maximum vent length
Number of 90º elbow Maximum vent length
3
23' (7.0m)
29' (8.8m)
2
35' (10.7m)
1
Unless a drain tee is used, the maximum vertical height of the vent system can not exceed 5'
(1.5m).
Horizontal extended installation (See Fig. 6).
The straight termination consists of 2 parts (sleeve and termination itself). Separate them before
installation.
1. Check the location of appliance and the path for the vent system. And calculate the required
number and combination of items (see the dimensions of items in Fig.1).
2. Check wall thickness where the vent system passes through, and select suitable horizontal
termination according to TABLE 2. Cut the opening for the sleeve with the diameter in TABLE 2.
(Cover the flue outlet to avoid debris from entering the appliance)
3. Adjust the length of the sleeve so that the end of the sleeve protrudes about 0.2" (5mm) from
the wall. Then fasten the sleeve with the screw provided.
*Remember a stamped letter on the sleeve.
4. When the opening is too large, twist the packing provided around the end of the sleeve after
peeling off backing paper from the packing.
5. Insert the sleeve to the wall and fasten with 4 screws provided. Use plugs provided if needed.
*Ensure the UP label on sleeve plate is at the top.
*If it isn't easy to insert the sleeve because the packing doesn't fit the wall, press down the packing
during insertion.
6. Seal between the end of the sleeve and wall, and between the end of inner sleeve pipe and
outer pipe.
7. Adjust the length of the termination by fastening it at the stamped number same as that in 2.
8. Fasten the condensation prevention plate with the screw provided if this plate is needed.
9. Insert the termination into the sleeve from inside wall so that 4 studs on sleeve plate are
inserted into each 4 holes on termination plate and fasten the termination to the sleeve with the
4 nuts provided.
*Ensure that the label on the termination is at the top.
10. Ensure that the end of air Intake pipe protrudes about 0.4" (10mm) from the sleeve.
11. Install the vent system from the appliance to straight termination with using straight lengths,
adjustable lengths, and elbows. If vent system have vertically installed lengths longer than 5'
(1.5m), or have 3 elbows, install drain tee directly on the appliance flue outlet and male-male
adapter before horizontal lengths.
Make sure that a continuously DOWNWARD slope of no less than 2º (1/4 in/ft) is maintained
in the horizontal portion.
Refer to Fig 4-3 & 4-4 page 45.
12. Support the vent system every 5' (1.5m) with support straps.
13. Attach facing plate for outer wall as required.
*Drill 3 pilot holes in the outer wall first. Then insert plugs to the holes and fasten the facing plate
to the wall with 3 screws provided. Locate the notch of the facing plate at the bottom of the plate.
*Seal between the facing plate and the wall. Do not seal the notch.
- 50 -
VENT PIPE INSTALLATION
3.
10.
Stamped letter
End of air intake pipe
About
0.2"
End of sleeve
Sleeve
Packing
4.
11.
UP
No less than 2º (1/4 in/ft)
12.
5' (1.5m)
Reducer
90º elbow
Plug
5.
Support strap
4 Screws
Straight length
UP
Straight termination
6.
Seal between
sleeve and wall
Horizontal extended installation without drain tee
Seal between
inner sleeve pipe
and outer pipe
No less than 2º (1/4 in/ft)
Seal between
sleeve and wall
Male-male adapter
5' (1.5m)
Reducer
90º elbow
7.
Support strap
Straight length
Stamped letter
Termination
Drain tee
Straight termination
8.
Condensation prevention
plate
Horizontal extended installation with drain tee
Screw M4 X 10
9.
UP
13.
3 Plugs
Label
3 Screws
4 Nuts
Facing plate
< Fig. 6 Detail of horizontal extended installation >
- 51 -
Notch
VENT PIPE INSTALLATION
Vertical installation
Vertical installation
Rain cap
Air intake pipe
Roof flashing
Straight length
Maximum height 23' (7m)
Maximum height 23' (7m)
Air intake pipe
Rain cap
Drain tee
Roof
flashing
90º elbow
No less than 2º
(1/4 in/ft) upward
Drain tee
< Fig. 7 Vertical installation >
Vertical installation.
Vertical installation means installation of vent terminal on flat or angled roofs. It consists of
rain cap, reducer, straight lengths, adjustable lengths, and elbows as shown in Fig. 7 install drain
tee directly on the appliance flue outlet.
A continuously UPWARD slope of no less than 2º (1/4 in/ft) should be maintained in the horizontal
portion. A typical installation is shown in Fig. 7.
It shall be limited to the maximum height 23' (7m).
Refer to page 38, Vent Pipe Installation, for maximum total length of vent pipe.
- 52 -
VENT PIPE INSTALLATION
Vertical installation (See Fig. 7).
1. Check the location of appliance and the path for the vent system. And calculate the required
number and combination of items (see the dimensions of items in Fig.1, page 41) of the vent
system. Check the pitch of roof where the vent system passes through.
2. Cut 5.3" (135mm) diameter openings(or suitable 'oval' for pitched roof) in each floor, ceiling,
and the roof where the vent system passes through.
3. Connect drain tee to the appliance flue outlet.
4. Install the vent system from the appliance to roof by using straight lengths, adjustable lengths,
and elbows.
Make sure that a continuously UPWARD slope of no less than 2º (1/4 in/ft) is maintained in the
horizontal portion.
Refer to Fig. 7 page 50.
5. Support the vent system every 5' (1.5m) with support straps.
6. Once the vent system reaches under the roof, set the parts of roof flashing. The parts required
and the connecting order of them depend on the pitch of the roof shown in Fig. 8.
7. Fasten the bottom part of roof flashing (cap) or (adapter) to roof with screws, nails or so on.
If the 4 holes at the 4 corners of the part is larger than screws or nails, insert the 4 washers
provided with the part.
8. If roof flashing (adapter) is used, connect roof flashing (base) to roof flashing (adapter) with the
bolts provided with the part.
9. Connect the pipe of roof flashing (cap) to vent system.
Adjust the angle of roof flashing (cap) so as to make the pipe of roof flashing (cap) vertical.
10. Seal between the parts of roof flashing and roof.
The pitch of the roof ; 20º-40º
Rain cap
Air intake pipe
Roof flashing (cap)
Roof flashing (base)
Roof flashing (adapter A)
The procedure of installation
The pitch of the roof ; 40º-55º
The pitch of the roof ; 20º or less
Rain cap
Rain cap
Air intake pipe
Air intake pipe
Roof flashing (cap)
Roof flashing (cap)
Roof flashing (base)
Roof flashing (base)
The procedure of installation
Roof flashing (adapter B)
The procedure of installation
< Fig. 8 Detail of vertical installation >
- 53 -
GAS LINE SIZING CHARTS
Maximum Natural Gas Delivery Capacity in Cubic Feet per Hour (0.60 Specific Gravity, 0.5" WC Pressure Drop)
PipeSize
Length in Feet
10'
20'
30'
40'
50'
60'
70'
80'
90'
100'
125'
44
1/2"
174
119
96
82
73
66
61
56
53
50
3/4"
363
249
200
171
152
138
127
118
111
104
93
1"
684
470
377
323
286
259
239
222
208
197
174
1 1/4"
1404
965
775
663
588
532
490
456
428
404
358
1 1/2"
2103
1445
1161
993
880
798
734
683
641
605
536
2"
4050
2784
2235
1913 1696 1536 1413 1315 1234 1165 1033
2 1/2"
6455
4437
3563
3049 2703 2449 2253 2096 1966 1857 1646
3" 11,412
7843
6299
5391 4778 4329 3983 3705 3476 3284 2910
3 1/2" 16,709 11,484
9222
7893 6995 6338 5831 5425 5090 4808 4261
4" 23,277 15,998 12,847 10,995 9745 8830 8123 7557 7091 6698 5936
Contact the Gas Supplier for Btu/Cubic Ft.
of the Supplied Gas.
1000 Btu/Cubic Ft. is a Typical Value.
Maximum Liquified Petroleum (Undiluted) Delivery Capacity in Thousands of Btuh (0.5" WC Pressure Drop)
PipeSize
Length in Feet
10'
20'
30'
40'
50'
60'
100'
125'
150'
1/2"
275
189
152
129
114
103
70'
96
80'
89
90'
83
78
69
63
200 '
55
3/4"
567
393
315
267
237
217
196
185
173
162
146
132
112
1" 1071
732
590
504
448
409
378
346
322
307
275
252
213
1 1/4" 2205 1496 1212 1039
913
834
771
724
677
630
567
511
440
1 1/2" 3307 2299 1858 1559 1417 1275 1181 1086 1023
976
866
787
675
2" 6221 4331 3465 2992 2646 2394 2205 2047 1921 1811 1606 1496 1260
** For reference only. Please consult gas pipe manufacturer for actual pipe capacities.
Maximum Capacity of Flex TracPipe in Cubic Feet per Hour of Natural Gas (0.60 Specific Gravity, 0.5" WC Pressure Drop)
PipeSize
Length in Feet
10'
20'
30'
40'
50'
100'
150'
200'
3/4"
206
147
121
105
94
60'
86
70'
80
80'
75
90'
71
67
55
48
1"
383
269
218
188
168
153
141
132
125
118
94
82
1 1/4"
614
418
334
284
251
227
209
194
181
171
137
116
1 1/2" 1261
888
723
625
559
509
471
440
415
393
320
277
2" 2934 2078 1698 1472 1317 1203 1114 1042
98 3
933
762
661
Maximum Capacity of Flex TracPipe in Thousands of Btuh Liquified Petroleum (0.5" WC Pressure Drop)
PipeSize
Length in Feet
10'
20'
30'
40'
50'
60'
70'
80'
90'
100'
150'
200'
3/4"
325
232
191
166
149
136
126
118
112
106
87
76
1"
605
425
344
297
265
241
222
208
197
186
143
129
1 1/4"
971
661
528
449
397
359
330
307
286
270
217
183
1 1/2" 1993 1404 1143
98 8
884
805
745
696
656
621
506
438
2" 4638 3285 2684 2327 2082 1902 1761 1647 1554 1475 1205 1045
** For reference only. Please consult gas pipe manufacturer for actual pipe capacities. TracPipe is a registered trademark of Omega Flex.
Maximum Capacity of Gas Flex Connectors in Cubic Feet per Hour
of Natural Gas (0.60 Specific Gravity, 0.5" WC Pressure Drop)
PipeSize
Length in Inches
12"
24"
36"
48"
1/2"
180
150
125
106
93
86
3/4"
-
290
255
215
197
1"
-
581
512
442
397
- 1470 1200 1130
960
1 1/4"
Maximum Capacity of Gas Flex Connectors in Thousands
of Btuh Liquified Petroleum (0.5" WC Pressure Drop)
60"
PipeSize
72"
Length in Inches
12"
24"
36"
48"
60"
72"
1/2"
288
240
200
169
149
137
173
3/4"
-
46 5
409
344
315
278
347
1"
-
930
825
708
638
556
930
1 1/4"
** For reference only. Please consult gas pipe manufacturer for actual pipe capacities.
- 54 -
- 2352 1920 1808 1536 1488
GAS PIPING
• Install the manual gas control valve in the gas inlet connection of MWH-180.
• A union should be used to connect the unit and the gas pipe.
• Check the gas type and the gas inlet pressure before connecting.
• Remove the screw from the test plug before checking the gas inlet pressure.
Connect the manometer to the plug with the silicon tube and measure the gas inlet pressure.
• The maximum and minimum gas inlet pressures are as follows.
< Natural Gas supply pressure >
Min. 4" W.C.
(102mmH2O)
Max. 10.5" W.C. (267mmH2O)
< Propane Gas supply pressure >
Min. 8" W.C.
(203mmH2O)
Max. 14" W.C.
(356mmH2O)
• Put the screw back in the test plug and fasten tightly.
• Make sure to conduct gas leakage test before operating MWH-180.
WATER PIPING
• Install a manual water control valve in the water inlet connection of MWH-180.
• A union should be used on both the hot and cold water supply lines for connection.
• Use soldering materials or piping that will not cause any deterioration of potable water.
NO LEAD!
• Purge the water lines to remove all debris and air.
• Make sure both the hot and cold water supply lines are connected correctly.
• A filter is placed at the water supply inlet to remove debris.
Clean the filter regularly.
Do not operate the unit without the filter in place.
In areas of heavy debris, such as with some wells, install a whole house water filter in line before
the unit.
• 15 PSI or higher water pressure is required to operate MHW-180.
- 55 -
PRESSURE RELIEF VALVE
• Install an approved pressure relief valve with every gas water heater installation.
• The pressure relief valve shall conform to the following requirements.
Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply Systems ANSI Z21, 22.
This pressure relief valve shall activate with the pressure of 150PSI.
• The pressure relief valve shall be installed in the outgoing hot water supply line according to the
manufacturer's instruction.
• No valves or shut off device shall be placed between the relief valve and the unit.
The discharge from the pressure relief valve shall be piped to the ground or into the drain
system to prevent possible burns to humans or animals. Hot water discharged from the relief
valve may cause severe scalding instantly and even death.
• Do not cap the relief valve and do not install any depressurizer or restriction device in the relief
line.
• Manually operate the pressure relief valve at least once a year to check if it functions properly.
ELECTRICAL CONNECTION
Warning
MWH-180 must be electrically grounded in accordance with local codes or in the absence of
local codes with the most recent edition of the National Electrical Code, ANSI/NFPA 70. In
Canada, all electrical wiring to the MWH-180 should be in accordance with local codes and
the Canadian Electrical Codes, CSA C22.1 Part 1. Do not rely on the gas or water piping to
ground the metal parts of the water heater.
Caution
• Label all wires prior to disconnection when servicing controls. Wiring errors can cause
improper and dangerous operation.
Verify proper operation after servicing.
Field wiring to be performed at time of appliance installation.
• Completely turn off the power before starting the work.
Do not turn the power on until the electric wiring is finished and all work is completed.
Otherwise electric shock or personal injury may result.
- 56 -
ELECTRICAL CONNECTION
• MWH-180 requires 120V AC at 60Hz.
Disconnect the power supply if the unit is not in use for a long time.
• Remove residual water in the unit when the power supply is off because the freeze prevention in
the unit will not activate, resulting in possible freezing damage.
• Do not let the power cord contact the gas piping.
• The grounding screw is located in the junction box attached to the outside of bottom plate.
• To prevent electrical shock, provide a ground with resistance less than 100Ω. An electrician
should do this work.
Surge protector
Power supply lead wire
(Black-hot / White-neutral)
Junction box
Power supply lead wire
Ground terminal
(Grounding screw)
- 57 -
WIRING DIAGRAM
- 58 -
WIRING DIAGRAM
- 59 -
DIAGNOSTIC POINTS
Component
Surge Protector
Water Flow Control Device
Measurement Point
Normal Value
Notes
Comp. No.
Wire Color
12
Brown-Blue
AC108~132V
Blue-Red
DC11~13V
Black-White
55~65 Ω
Green-White
55~65 Ω
Purple-White
55~65 Ω
Orange-White
55~65 Ω
Red-Black
DC11~13V
Power Supplied to Unit
White-Black
DC5~7V or DC0~1V
Power Supplied to Unit
DC2~12V
Flame Condition
10
Power Supplied to Unit
Water Flow Sensor
2
Modulating Solenoid Valve
1
Gray-Gray
Remote Controller
9
Black-Black
DC11~13V
Power Supplied to Unit
Red-Blue
DC155~165V
Power Supplied to Unit
Yellow-Blue
DC14~16V
Revolving Condition
Orange-Blue
DC2~6V
Revolving Condition
White-Blue
DC8~12V
Revolving Condition
White-Green
AC50~150V
After Ignition
White-Flame Rod
DC1~20µA
Flame Condition
Fan Motor
4
65~77 Ω
Flame Rod
3
Over Heat Switch
3
Yellow-Yellow
Below 1 Ω
Igniter
7
Black-Black
AC90~110V
Thermal Fuse
5
Yellow-Yellow
Below 1 Ω
Main Solenoid Valve
5
Yellow-Yellow
Solenoid Valve 1
5
Yellow-Orange
Solenoid Valve 2
5
Yellow-Blue
Outgoing Thermistor
3
White-White
Air Thermistor
3
White-White
Heat Exchanger Thermistor
3
White-White
DC80~100V
Flame Condition
1.4~1.6k Ω
DC80~100V
Flame Condition
1.55~1.75k Ω
DC80~100V
1.5~1.7k Ω
40º F
80º F
120º F
160º F
19~21k Ω
7.5~8.5k Ω
3.3~3.9k Ω
1.7~1.9k Ω
Transformer
Primary
C
Brown-Blue
AC108~132V
45~55 Ω
Secondary
C
Black-Blue
AC90~110V
43~53 Ω
- 60 -
Igniting Condition
Flame Condition
SCHEMATIC DIAGRAM
Air Supply Duct
Exhaust Duct
Heat Exchanger
Over Heat Switch
Frost Sensing Switch
Heat Exchanger
Thermistor
Flame Rod
Anti-Frost Heater
Thermal Fuse
Burner
Electrode
Air Thermistor
Igniter
Fan Motor
PCB
Solenoid Valve SV2
Remote
Controller
Solenoid Valve SV1
Water Flow
Control Device
Modulating
Solenoid Valve
Main Solenoid
Valve
Surge Protector
Outgoing
Thermistor
Water Flow Sensor
Water Filter
AC120V
Drain Plug
Hot Water
Outlet
Water
Inlet
- 61 -
Gas
WIRING REMOTE CONTROLLER
The Main remote controller model is CMR-2250. (P/N 3748)
The Bath remote controller model is YST-2250. (P/N 3749)
These controllers are to be fitted in the following locations:
Main remote controller - kitchen or laundry.
Bath remote controller - bathroom.
Only one of each type of controllers can be connected to one MWH-180 water heater.
(i.e. Installations with two CMR-2250 or two YST-2250 will not function properly.)
The remote controllers can be wired in parallel only depending on the distance from MWH-180 to
the remote controllers.
Be sure to peel the protective film off the surface of the remote controller after the installation.
The surface is covered with a film to prevent scratches during installation.
Caution
The appliance should always be disconnected from the power supply before REMOTE
CONTROLLERS are connected.
• Connect the cord to the terminal block of water heater.
As remote controller cables are nonpolarized, they do not have specific plus and minus.
Be sure not to touch other electronic components with the screwdriver.
• Replace the front panel of MWH-180.
Remote controller
connection terminals
Remote controller cable
Cable clamp
- 62 -
MAIN REMOTE CONTROLLER CMR-2250 (P/N 3748)
1) Safety precautions on Main remote controller installation.
• Connect remote controller cable after heater is unplugged.
• Never install Main remote controller above a combustion
appliance like hot plate or a kitchen range.
The heat will cause electrical component problems, or deform
the exterior.
• Install Main remote controller out of the reach of steam,
water drop, spray of water from tea kettle, or electrical pot.
• Do not put Main remote controller in direct sunshine.
• It is convenient to install it where it will be used most frequently.
• Do not install Main remote controller at the place where any
commercial chemicals like ammonia, sulfur, chlorine, ethylenic
compound and acids etc are used.
• The remote controller cables carry low voltage, 12VDC digital.
Bad examples
Chemicals
Do Not
Remote controller
Remote controller
2) Installation of Main remote controller.
fitting bracket
• Detach the fitting bracket from Main remote controller by sliding
it down.
• Attach the fitting plate to wall.
• Install conduit inside of wall in advance and secure the wiring box.
• Pass remote controller cables through conduit.
Then pass the cables through the hole of the fitting bracket and pull them out.
• Attach the fitting bracket with screws adjusting the screw hole to the wiring box.
• Connect the remote controller cables to the terminal for the remote controller of PCB.
In case of installing of the fitting bracket for remote controller.
Align the slots of Main remote controller’s back to 4 hooks on the fitting bracket.
Then slide them on from the top.
Wiring box
Hook
Slot
Remote controller
fitting bracket
Terminal
Remote controller
cables
Screw
Hole for wiring
In case you are not using the fitting bracket of the remote controller.
Wiring box
Detach right-and-left covers of the remote
controller and fix them to the wall directly with
wood screws. Then attach the covers again.
(You can detach the covers by catching the
bottom corner’s slot with nail.)
- 63 -
Cover
Wood screw
Cover
BATH REMOTE CONTROLLER YST-2250 (P/N 3749)
1) Safety precautions on Bath remote controller installation.
• Before remote controller installation, check the hole position considering wall stud location.
• Note : Do not dismantle the remote controller due to water-proof design.
• Do not install remote controller where water will contact the remote controller directly.
• The remote controller cables carry low voltage, 12VDC digital.
2) Installation of Bath remote controller.
• Drill a hole (more than dia about 1/2" (12mm)) in a wall for the remote controller cables.
• After passing the remote controller cables through the hole, remove the packing’s back paper
of remote controller. Then attach the remote controller to the wall.
• Detach both end covers of remote controller and fix the remote controller to the wall with wood
screws(2 pcs) in the screw holes provided. (You can detach the covers with catching the
bottom corner’s slot with nail.) Do not tighten the screws excessively, as the screw hole may
be damaged. In case of mounting the remote controller on tile, cement or mortar, use an
expansion bolt.
• Reattach the cover and caulk with silicone around surrounding of the remote controller.
Remote controller cables
Caulking
Expansion bolt
Remote controller
packing
Wood screw
Cover
Remote controller
cables
Bath remote
controller
Caulking
Cover
In case of use of store-bought cables.
• The remote controller cable can be extended up to 100' (30m) by splicing the cable and
using 18 gauge wire to extend the cable to the appropriate length.
• Cut the connector of the remote controller lead wire and cut remote controller lead wire and
store-bought cables’ coating in 0.2" (5mm) length.
• Insert the end of remote controller cables to clamping connector and caulk using a caulking
tool.
• Caulk the store-bought cables inserted in the clamping connector using the caulking tool.
- 64 -
TESTING OPERATION
• Follow the steps below, to ensure the MWH-180 has been properly installed.
Preparation for testing operation.
1. Fully open the water supply main valve.
2. Flush out the water supply piping to clean out any installation debris, clean out filter.
3. Turn on power to unit and open gas supply valve.
Testing operation.
1. Operate the unit according to “ Remote controller operation ” in the instruction manual.
2. Make sure the unit operates normally.
• Does the burner ignite and shut off properly? Check the combustion lamp.
The burner may not ignite at first until the air in the gas supply pipe is driven out.
Repeat the procedure until it ignites.
• Is temperature setting workable?
Check if the temperature can be adjusted as desired.
Procedure after testing operation.
• If the residence is not ready for habitation or the unit will not be used for an extended time, the
residual water in the unit and the pipe may freeze and damage the unit, or the residual water in
the heat exchanger may deteriorate.
Be sure to remove the water in the unit and the pipe. Refer to the instruction manual.
1. Close the gas supply main valve.
2. Close the water supply main valve
3. Take off the water filter (drain stopper), drain the valve, and remove the water.
Take this procedure when the unit cools down after the testing operation.
4. Disconnect the power, or turn off the power supply.
5. Open the faucet and shower faucet (if any) and remove the water.
6. Leave the unit in this condition until ready to use.
Explanation to customers.
Fill out the warranty form with the customer and send to it MPI.
Explain the “ How to use the unit ” section of this instructional manual to the customer.
- 65 -
INSTRUCTIONS FOR CONVERSION
Instructions for converting the MWH180 from nat. gas to LP gas or LP gas to nat. gas.
DANGER: Serious injury or death can result to individuals who are not licensed professionals
properly trained in performing conversions. Proper tools and safety gear are always required.
If you are not a professional trained in conversions do not attempt to perform a conversion.
WARNING: This conversion should only be performed by a qualified gas company, plumber,
HVAC technician, or trained service person familiar with gas fired equipment. This person
should have tools to perform the conversion, check gas pressures, re-adjust gas pressures if
necessary, and leak test the unit once the conversion is complete.
To conver t to Natural gas you will need to contact your local MWH supplier and order
part# 3724-2 Damper and part# 3722-2 Manifold Assembly. For conversion to Propane part#
3724-1 Damper and part# 3722-1 Manifold Assembly will be needed.
MPI P/N
Description
3722-1
Manifold Assembly (Propane Gas)
3722-2
Manifold Assembly (Natural Gas)
3724-1
Damper (Propane Gas)
3724-2
Damper (Natural Gas)
WARNING: If you do not follow these instructions
exactly, a fire or explosion may result causing
property damage, personal injury or loss of life.
Procedure
Illustration
Step 1:
(1) Remove the four screws from front panel,
and place on the side so that they not get
lost or damaged.
(2) Remove wires from flame sensor and
electrode.
(3) Remove the set screws fixing the
Manifold Assembly (M4 × 7pcs, M4 with
washer × 3pcs ).
(4) Remove Manifold Assembly by gently
pulling it from both sides. Once Manifold is
removed make sure that the two O-rings that
seal between the Manifold and gas valve are
fixed in their groved surfaces. Should an
O-ring stick to the Manifold or drop out,
gently peal off the O-ring, inspect both
O-rings to make sure they are clean and not
damaged, then reinsert into groves in the
Gas Control Assembly. If either O-ring is
damaged it should not be reused but
replaced.
M4 × 7 pcs
Manifold Assembly
- 66 -
M4 with washer (3 pcs)
INSTRUCTIONS FOR CONVERSION
Procedure
Illustration
Step 2:
Damper setscrew (2 pcs)
(1) Remove set screws (2pcs) fixing the
Damper and pull the Damper out downward.
(2) Replace Damper with appropriate one
stamped LP or Nat.
LPG
Gas type engraved mark
NAT
Gas type engraved mark
Note: Damper slides up in between the
Burner and the Front Panel, housing the
Flame Rod and Electrode, leaving Gasket
exposed for sealing to the Manifold.
(3) Re-attach the two screws to secure the
Damper.
Pull out downward
Step 3:
When reinstalling the new Manifold make sure the three fine thread screws w/ washers are used
at the Gas Control Valve, and that there are no wires pinched under the Manifold before any
screws are tightened. Once it has been confirmed there are no obstructions and the Manifold
can seal properly to the Gasket on the Burner as well as the Gas Valve O-rings then all screws
should be tightened firmly and evenly.
Step 4:
The DIP Switches in the illustration below can be adjusted without removing the Circuit Board.
Familiarize yourself with their location and position, then adjust number 1 to appropriate gas
type.
(The illustrated switch settings show the factory settings for the LPG as the gas type.)
1 2 3 4 5 6 7 8
OFF
To switch gas type (LPG or natural gas)
To fix to the minimum capacity level
To fix to the maximum capacity level
To change prolonged exhaust mode
(7 and 8 should be set depending on exhaust length before starting this conversion)
- 67 -
INSTRUCTIONS FOR CONVERSION
Step 5: Gas Pressure Checking and Setting Procedure
1. Preparation
(1) It is assumed that the inlet gas pressure coming into the unit is within the min. to max.
allowed, as per the Data Rating Plate, for gas type to be used. The gas inlet pressure can be
checked at the threaded hose fitting of the 3/4 inch inlet gas connection to the unit by:
• turning off the gas valve,
• removing the screw from the hose fitting,
• attaching a gas pressure manometer,
• opening the gas valve and checking the incoming gas pressure.
"Should the pressure be out of range, adjustments need to be made by the gas supplier prior
to any internal adjustments".
If inlet pressure is within range close gas valve, remove Gas Pressure Manometer, reinstall
screw with washer into the threaded hose fitting, and reopen gas valve.
(2) Make sure the appliance is not in operation. Then, remove the screw from the Manifold
pressure check inlet. (Do not mix the screw up with the front cover screws as they are the
same type threads)
(3) Connect the hose of the manometer to the pressure check fitting.
2. Adjusting Manifold pressure settings <Minimum pressure should be set before
setting the maximum pressure>
(1A) Make sure that "DIP Switch" No.1 is set to the position for the appropriate gas type.
(1B) Minimum Manifold gas pressure 0.4 inches w.c.
Maximum Manifold gas pressure 2.4 inches w.c.
Note: A small Phillips head screwdriver will be needed if gas pressures are out of
specification and need to be re-adjusted.
(2) After ignition and combustion is started, by opening the hot water supply valve, set "DIP
Switch" No. 5 to ON position to set the combustion at a minimum capacity level. By turning
the minimum gas adjusting control knob under the "DIP Switch", set the gas pressure for
the minimum capacity level. Set the "DIP Switch" No. 5 to OFF.
- 68 -
INSTRUCTIONS FOR CONVERSION
(3) With the unit still running, set "DIP Switch" No. 6 to ON position to set the combustion at a
maximum capacity level. At this time, a substantial amount of water should be supplied.
"Multiple faucets should be opened to prevent water from boiling, as the maximum capacity
is forced, if the water temperature is high, the heated water may reach its boiling point."
(4) Set the gas pressure for the maximum capacity level by turning the maximum gas adjusting
control knob under the minimum gas adjusting control knob. Then, set the "DIP Switch" No.
6 to OFF.
(5) Shut the hot water supply valve. Open the valve again for combustion. Repeat steps 2 and
4 to check that the settings are correct.
(6) Shut the hot water supply valve to stop combustion. Disconnect the rubber hose of the
manometer from the pressure check fitting. Seal the hole by installing and tightening the
screw.
(7) Restart the unit with full water supply and check for any gas leakage at the pressure check
screw and around the gas manifold itself. If the gas pressure inlet screw was removed and
reinstalled, it should also be leak tested.
Dip Switch
Min.
Max.
Maximum gas adjusting control knob
Nozzle pressure
Minimum gas adjusting control knob
Threaded Hose Fitting
Rubber Tubing
Step 6:
Remark the gas type label on the upper left hand side of the cabinet with the new gas type.
Reinstall the front cover with its four screws.
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WARRANTY
Monitor Products, Inc.
LIMITED WARRANTY
MWH-180 Instantaneous Water Heater
Monitor Products, Inc. hereby warrants this gas water heater to be free from defects in materials
and workmanship, under the conditions stated below. This warranty is extended to the original
purchaser, but only while the MWH-180 remains at the original installation site.
Heat Exchanger
The Heat Exchanger is covered for ten (10) years of normal residential use. Monitor Products,
Inc. (MPI) will repair or replace the heat exchanger at MPI's sole discretion.
If the MWH-180 is used in other than a single family dwelling, or if the MWH-180 is supplied with
pre-heated or circulated water, then the heat exchanger warranty shall be limited to three (3) years
and all other parts are limited to two (2) years.
Parts
For all parts other than the heat exchanger, should MPI determine after an examination that there
has been a part failure within five (5) years of the date of installation, MPI will either repair or
furnish a replacement part at the sole discretion of MPI. The replacement part is warranted for the
remainder of the original warranty.
Standard labor
MPI will pay for standard labor costs at fixed flat rates depending on defect or part failure (not
including dealer or service person travel time) associated with repairs or replacements within
one (1) year of the date of installation through its authorized servicers if determined by MPI or
authorized servicers to be defective under normal residential use. Ready access to the MWH-180
for service is the responsibility of the owner.
Service and Repair Costs
After the first year, MPI will provide repair or replacement parts or product only under this limited
warranty. The owner will be responsible for any other costs incurred including labor costs for
servicing or replacing the part or unit, shipping, delivery and handling of the replacement part
or product, costs for permits or materials necessary for the repair, or incidental costs resulting
from damage external to the unit resulting from the failure.
Conditions and Limitations
The warranty coverage is limited to the original purchaser of the MWH-180, in its original
installation location, and only if the installation is in the United States of America or Canada.
This warranty will only apply if the water heater is installed in accordance with all state, local, and
federal codes, and if the installation, service, and maintenance are performed following the
Installation and operation manual supplied with this unit.
This warranty does not cover any failures or operating difficulties due to accident, abuse, misuse,
alteration, misapplication, acts of God, improper installation, improper maintenance or service,
water quality, scale buildup, or for any other causes other than defects in material and
workmanship. This warranty does not cover any units whose serial number or manufacture date
has been defaced. This warranty does not cover a unit when used as a spa or pool heater.
This warranty does not cover damage resulting from fire, flood, water freezing inside the unit or
piping, or from use with non-potable water, or water with high pH or hardness levels.
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WARRANTY
This warranty does not apply if the water supply to the water heater does not meet the National
Secondary Drinking Water Regulations as set forth in the U.S. Code of Federal Regulations, 40
CFR, Chapter 1, Part 143. The recommended water quality levels are as follows;
Description
Maximum
Levels
pH
6.5 - 8.5
Total
Hardness
Aluminum
Chlorides
Copper
Iron
Dissolved solid)
TDS (Total
<500 mg/l
<200 mg/l
<0.2 mg/l
<250 mg/l
<1.0 mg/l
<0.3 mg/l
Manganese
Procedure For Obtaining Performance Under This Warranty
In order to obtain performance of the obligations under this warranty, the original purchaser must
promptly (in no event later than thirty (30) days after discovery of the defect) notify the selling
dealer authorized to service the MWH-180, or MPI at 732-329-0900 for the name of a local
servicing dealer. All claims must be accompanied by a proof of purchase: sales receipt, cancelled
check, or a warranty registration card mailed to MPI within 30 days of purchase.
Legal rights
This warranty gives you specific legal rights and you may also have other rights which vary from
state to state.
NOTE:
Some states do not allow: (A) Limitations on how long an implied warranty lasts; or(B) The
exclusion of limitation of incidental or consequential damages, so the above limitations or
exclusions may not apply to you.
No person has the authority to orally, or in writing vary the terms, conditions, or exclusions of this
warranty: nor to express or imply merchantability or fitness for a particular purpose beyond this
warranty.
Monitor Products, Inc.
7A & 7E Marlen Drive
Robbinsville, NJ 08691
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