PrecisionTemp cIAPMO-T 550NSP-EC User manual

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CRITICAL INSTALLATION WARNINGS
• All combustion air must be supplied from outside the RV, and all
products of combustion must be vented to outside the RV.
• DO NOT vent water heater with venting system serving another
appliance.
• DO NOT vent water heater to an outside enclosed porch area.
• Protect building materials from flue gasses.
• DO NOT modify water heater in any way.
• DO NOT alter water heater for a positive grounding system.
• DO NOT HI-POT water heater unless electronic ignition system
(circuit board) has been disconnected.
• DO NOT use battery charger to supply power to water heater
even when testing.
This water heater design has been certified to CSA ANSI Z21.10.3 *
CSA 4.3:19 standard as a direct vent automatic instantaneous water
heater / furnace, designed to be installed in recreational vehicles or
Installation, Operation and Maintenance
Effective 3/23
manufactured (mobile homes). This water heater is not for use in
space heating applications.
SERVICE CALLS & QUESTIONS
Locations and phone numbers of qualified Service Centers can
be found at our website www.precisiontemp.com or
call 800-934-9690 Ext. 110 to obtain service information.
—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
• Evacuate all persons from the
vehicle.
• Shut off the gas supply at the gas
container or source.
• Do not touch any electrical switch,
or use any phone or radio in the
vehicle.
• Do not start the vehicle’s engine or
electric generator.
• Contact the nearest gas supplier or
qualified service technician for
repairs.
• If you cannot reach a gas supplier
or qualified service technician,
contact the nearest fire department
• Do not turn on the gas supply until
the gas leak(s) has been repaired.
Installation and service must be
performed by a qualified installer,
service agency, OEM or the gas
supplier.
WARNING: If the information in these
instructions is not followed exactly, a
fire or explosion may result causing property
damage, personal injury or loss of life.
The installation, must comply to local codes or in the
absence of local codes must conform to one of the
following:
* The National Fuel Gas Code, ANSI Z223.1/NFPA 54
and/or CSA B149.1, Natural Gas and
Propane Installation Code
* The Manufactured Home Construction and Safety
Standard, Title 24 CFR, Part 3280 and/or
CSA Z240 MH Series, Manufactured Homes; or
* Recreational Vehicle, NFPA 1192, and/or CAN/CSA-
Z240 RV Series.
If an external electrical source is utilized, the appliance,
when installed, must be electrically grounded in
accordance with local codes or in the absence of local
codes, with the National Electrical Code, ANSI/ NFPA 70,
and/or CSA C22.1, Canadian Electrical Code, Part 1.
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CLEARANCE Requirements
Sides, top and bottom - 0"
Back - Enough to make connections, but no less
than 2.5"
Front - Enough to remove access cover for service,
but no less that 10". Unit should be installed where it
can draw combustion air into the bottom directly from
the coach exterior and flued through the 2" flue pipe
to the exterior. The combustion air source and flue
pipe must be totally isolated from the inside of the
coach.
LPG GAS ON DEMAND
WATER HEATER
Model
550NSP-EC
3428 Hauck Road Suite G
Cincinnati, OH. 45241
Phone: [phone] * 800-934-9690
Fax: [phone]
www.precisiontemp.com
Cincinnati, OH 45237 1-800-934-9690
www.precisiontemp.com
TwinTemp Gas Instantaneous Water Heater and Space Heating Appliance
Complies with the requirements of ANSI Z21.10.3b
This is a power vent combination automatic instantaneous water heater and space
heating appliance for installation in a manufactured home (mobile home) or
recreational vehicle, suitable for water (potable) heating and space heating. This
appliance must be installed in accordance with local codes or, in the absence of
local codes, the Standard for Recreational Vehicles, ANSI A119.2/NFPA 501C.
Patent Pending.
BTU /HR Input:
Fuel:
Inlet Pressure:
Manifold Pressure:
Power Input:
Operating Pressure:
Max. Water Temp:
Orifice Size:
Tank Volume:
Recovery Rating:
Elec. Element(s):
55,000 –12,000
Propane
10.5” WCI Min. to
14” WCI max.
1.30” – 9.20” WCI
12 VDC 10 Amp
125 PSI Max.
(8.6 Bar) Max.
145°F (63°C)
#71 x 12
2.5 US Gal (9.5L)
54
120vac, 60Hz, 12.5amps
Serial No:
“Clear Window (0.4” x 2.1”)”
Minimum clearances from combustible
and noncombustible construction is 1”
(25mm) on the sides, back and top.
WARNING:
If the information in these
instructions is not
followed exactly, a fire or
explosion may result
causing property
damage, personal injury
or death.
FOR YOUR SAFETY:
Do not store or use
gasoline or other
flammable vapors and
liquids in the vicinity of
this or any other
appliance.
Installation and
Service:
Must be preformed by a
qualified installer, service
agency or gas supplier.
WHAT TO DO
WHAT TO DOWHAT TO DO
WHAT TO DO IF YOU SMELL GAS:
IF YOU SMELL GAS:IF YOU SMELL GAS:
IF YOU SMELL GAS:
1. Evacuate all persons from the vehicle.
2. Shut off the gas supply at the gas container or source.
3. Do not touch any electrical switch, or use any phone or
radio in the vehicle.
4. Do not start the vehicle’s engine or electric generator.
5. Contact the nearest gas supplier or qualified service technician for repairs.
6. If you cannot reach a gas supplier or qualified technician, contact the
nearest fire department.
7. Do not turn on the gas until the gas leak(s) has been repaired.
Label Specifications:
Label Size: 6.0” Wide x 8.5” Tall
Radius Corners:
Label Corners: 0.25”
Inside Note Boxes: 0.12”
“Warning”/”For Your Safety” Box: 2.0” Wide x 3.5” Tall with a 0.05” Thick Border
“What to do if……” Box: 5.5” Wide x 1.9” Tall with a 0.05” Thick Border
cIAPMO-T®
Certified to ANSI Z21.10.3 / CSA4.3:19
REV 3/23 1.

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Cold In
Gas Connection
Hot Out
GENERAL INSTALLATION
The following instruction describes the most common type of
installation for the water heater. The most common mounting
location would be in the “basement” or luggage compartment.
Consult your Field Auditor, Account Manager, or the
PrecisionTemp Service Department if you have additional
questions.
Mounting Unit
Unit should be located to allow hookups on the back and
access to the front panel for servicing. Note the locations
of the flue pipe, combustion air cut-outs and mounting
holes on the diagram below. The dotted line represents
the base of the unit. Be sure these holes will not interfere
with any framing members or other wiring or equipment
under the coach. When the appliance is installed directly
on carpeting, it shall be installed on a metal or wood panel
extending beyond the full width and depth of the appliance
by at least 3 inches (76.2 mm) in any direction. The
appliance should be located in an area where leakage of
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 cannot be avoided, it is
recommended that a suitable drain pan, adequately
drained, be installed under the appliance. The pan must
not restrict combustion air flow.
Be sure to observe proper clearances around the unit.
1. Referring to the diagram, locate the proper mounting
location and cut a hole with a diameter of 3.5” to
accommodate the flue pipe. A 4.5” hole for the
combustion air should be cut so that it is under the
bottom air intake grill. This hole must be located
where it cannot be covered or blocked and to assure
all combustion air comes from the outside.
2. Mount the 2 brackets to the bottom of the unit on
either side using the supplied 1/4” bolts.
3. Place unit into place to locate 4 mounting holes and
mark their positions.
4. Remove the unit and drill the 4 – 3/8” mounting
holes in the floor.
5. Apply a rubber gasket or sealant around the
combustion air hole on the bottom of the unit and
mount unit in place assuring the seal is in complete
contact with the mounting surface to assure an air
tight seal. Note: Do not use glue.
6. Screw or bolt into place.
Exhaust Pipe Installation
After the unit is secured into place, install the exhaust
pipes as follows: (exhaust pipes not included)
1. Fit a 2"id x 2"od elbow onto the 2” flue tailpiece
from the bottom of the unit and push flare side of
the elbow up onto the flue tailpiece of the unit.
2. Position enough 2"id x 2"od straight pipe out so
that it points about 30° to the rear. Allow at least
6” to protrude from under the RV or Tiny Home.
3. Now remove the pipe and coat the inside
diameter of the flue pipe elbow with high
temperature silicone sealant or equivalent.
4. Push and secure the elbow pipe onto the
tailpiece. This can be done with self-tapping
screws or by drilling pilot holes before inserting
metal screws. At least two screws must be used
to secure the pipe.
5. Push and secure the straight pipe onto the
elbow. Screw or clamp exhaust into place. Use a
proper exhaust bracket to support flue pipe to
the bottom of the coach.
7. Connect plumbing to water lines taking care to make
correct “COLD” and “HOT” orientation. Connect 3/8” FM
flared LP gas line to 3/8” M flared gas fitting. Assure the
water and gas line grommets continue to be intact and
properly inserted in the case holes, with no gaps or
openings where the lines pass through the case. See
illustration.
8. Turn on the gas and check the water heater and all
connections for gas leaks with a leak detecting solution.
9. Turn on water supply line and check for water leaks.
All connections must be made using TWO
(2) wrenches to avoid twisting and damaging
lines. Damage voids the Warranty!
2.
4.5”
Flue Pipe Opening
4.25”
Combustion Air
Opening
4.5” Minimum
Gasket or Sealant between unit
base and mounting surface
3/8” mounting hole X 4
Front access door-
do not block
Back - Allow enough clearance for hookups
9.0”
10.1”
6.25” 11.0”
13.5”
13.5”
Mounting Bracket X 2
9.5”
5.56
3.5”
1.5” HOLE
1.625”
2.875”

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CAUTION ELECTRICAL DAMAGE
Label all wires prior to disconnection when servicing controls.
Wiring errors can cause improper and dangerous operation.
Verify proper operation after servicing.
3.
WIRING INSTRUCTIONS
The heater must be connected to fully rectified
12 VDC power supply rated at 5 amps. Takecare
to assure that the RED wire is connected to
(positive) +12 VDC supply lead and the Green wire
is connected to (negative) -12 VDC supply lead.
Reversing polarity or connecting to AC power will
damage the equipment and is not covered by
warranty.
The heater, when installed, must be electrically
grounded in accordance with local codes or, in the
absence of local codes, with the National Electrical
Code, ANSI/NFPA 70 and/or the CSA C22.1, Canadian
Electrical Code.
The appliance must be disconnected from the gas
supply piping system during any pressure testing of the
system at test pressures in excess of ½ psi. The
appliance must be isolated from the gas piping system
during any pressure testing at test pressures equal to
or less than ½ psi. Pressure inlet to valve, 13” W.C.
maximum, 11” W.C. minimum. Pressure at outlet of
valve is factory set at 10”. Burner manifold pressure is
W.C. 8.9” W.C. +/- .2” at tap on burner manifold.
PRESSURE RELIEF VALVE
THIS VALVE IS A SAFETY COMPONENT AND MUST
NOT BE REMOVED FOR ANY REASON OTHER
THAN REPLACEMENT. This water heater is equipped
with a pressure relief valve that complies with the
standard for Relief Valves and Automatic Gas Shutoff
Devices for Hot Water Systems, ANSI Z21.22 / CSA
4.4.
This valve protects against excessive water expansion
only. This water heater has separate and dedicated
protection for excessive heat.
If you use a discharge line, do not use a reducing
coupling or other restriction smaller than the outlet of
the relief valve. Allow complete drainage of both valve
and line.
FOR REPLACEMENT PARTS:
• DO NOT install anything less than a pressure relief
valve certified by a nationally recognized testing
laboratory that maintains periodic inspection of product
of listed equipment or materials, as meeting
requirements for Relief Valves and Automatic Gas
Shutoff Devices of Hot Water Supply Systems, ANSI
Z21.22 / CSA 4.4. Valve must have maximum set
pressure not to exceed 100 psi.
• Install replacement valve into opening provided and
designated for this purpose on water heater.
• Installation must conform with local codes or in the
absence of local codes, Standard on Recreational
Vehicles, ANSI A119.2 or CAN/CSA-Z240RV.
550-NSP EC SCHEMATIC
Flow Meter
Fuse
GND
Green
Black
Red
Green
Red
Brown
Brown

1) Pressurize the water system by turning on pump or
city water pressure.
2) Purge all air from the system by turning on the
faucets until a steady stream of water flows.
3) Turn on the 12V DC power supply.
4) Turn on the LP supply at the tank and the manual gas
valve (if installed).The water heater will remain
dormant until a water tap is opened and the heater
senses water flow of at least 0.5 GPM.
5) Turn on the hot water tap to full open. The heater will
fire up within several seconds and hot water will flow
from the tap in the time it takes to traverse the lines
from the heater to the faucet. (If this is the first usage,
you may have to turn the water on and off several
times to purge the LP gas lines of air. If the heater
fails to light or the lockout lamp (optional) illuminates,
turn the power switch OFF, then ON to reset the
ignition control. After ignition water flow can be
reduced cold water added as desired.
6) To shut off the water heater, shut off the water. Shut
off power at remote switch or breaker.
7) Should overheating occur or the gas supply fail to
shut off, turn off the “ON/OFF” power switch.
A Note About “Navy Showers” When Dry Camping
It is recommended to take a shower just like you would at
home. That is, leave the water running through the entire
shower. The hot water system is designed to deliver a
continuous, comfortable flow of hot water and that’s the
way it works best.
Shutting off the shower with the shower head button
wastes water. Each time this is done, the shower head
“trickles”, filling the hot water line with cold water. This
cold water has to be purged from the line each time the
shower head is turned back on. Tests have shown that
this will not save water and sometimes uses more water
than leaving the shower run continuously.
ELECTRONIC IGNITION MAINTENANCE
•The water heater comes factory-equipped with a fused
circuit board, which will protect the circuit board from
wiring shorts. If the fuse should activate, the water heater
will not operate. Before replacing the fuse, check for a
short external to the board. Once the short is corrected
replace the 5 amp fuse with a standard ATO style fuse. Do
not install a fuse larger than 5 amps.
•If the fuse is good and the unit is inoperative, check for
excessively high voltage to the unit (more than 14 volts).
Winter Operation and Winterizing Water
This heater is equipped with freeze protection that helps
prevent freezing under most conditions. In order for it to
function, 12 VOLT AND GAS SUPPLY MUST REMAIN
TURNED ON. This allows the burner to fire and electric
elements to protect the system. Any freezing of the water
heater or other plumbing components can cause severe
damage that is not covered by warranty.
Winter Traveling Operation:
In some areas all LPG appliances must remain off
when coach is in motion. If this is the case, drain
heater as follows:
1. Turn off water pump and the power and gas to the
heater. Open the pressure relief valve by lifting the
handle to a 90° position from the normal position.
2. Open at least one hot and cold water tap in the
coach. This should drain the system.
Winterizing Procedure:
Before storing the system for the winter, the plumbing
system must be winterized. This can be done by either
of the following methods:
1. All water should be drained from the system. To
do this, open one tap at a time using compressed
air to purge the system of all water.
2. Recommendations of your coach manufacturer
should be followed. The water system can be filled
with RV, non-toxic anti-freeze. When you see the
anti-freeze coming from the hot water tap, the
heater is protected.
4.
General Information and Maintenance
•Periodically inspect the venting systems to assure
that it is clean with no obstruction.
•Keep appliance area clear and free from combustible
materials, gasoline and other flammable vapors and
liquids.
•LPG and Water systems must be turned on
•Have gas pressure tested periodically. (should be set
at 11 inches of water column with three appliances
running)
•Drain water at regular intervals (at least one time
during the year)
•Drain water heater before storing the RV or Tiny
home for the winter or when the possibility of freezing
exist.
•Keep vent and combustion air grill clear of any
obstructions.

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NSP-550-EC Component Layout
NOTE
COMPONENT LAYOUT OF
RV-550-EC IS IDENTICAL TO
NSP-550-EC EXCEPT FOR FLUING
ORIENTATION WHICH FLUES
THROUGH TOP/FRONT RATHER
THAN BOTTOM.
1. Hall Sensor Flow Meter
2. Power Vent
3. Fluing Vacuum Switch
4. Combination Gas Valve
5. Igniter / Proofing Probe
6. Manifold and Burner
7. Finned Tube Heat Exchanger
8. Flue Hood
9. Flue Pipe
10. T-In Thermistor
11. T-Mid Thermistor
12. T-Out Thermistor
13. 165°F ECO
14. 100 PSI Pressure Relief Valve
5.
15. Gas Modulation Valve
NOT PICTURED
16. 12 VDC Relay
17. Control Board
18. Direct Spark Ignition Board

550-EC OPERATING INSTRUCTIONS
The 550-EC is designed to give a continuous flow of hot water as long as required and maintain
temperature within the capacity of the heater ( 5°F temperature rise at one GPM). The
temperature on your water heater has been factory set to approximately 120°F. It is not
recommended that you change this setting. Doing so could result in dangerously hot
temperatures that could result in severe injury. If it is necessary to change the setting refer to
the Service Manual or call PrecisionTemp.
The heater is dormant until a hot water tap is opened. The heater will not fire at very low
flows; i.e., under 0.5 GPM. During normal operation the 550-EC will have a steady flashing
green LED light on the green control board. A red flashing LED indicates a self diagnostic
trouble code; refer to the Service Manual or call PrecisionTemp for assistance. When
adjusting water temperature it is best to start with hot only and slowly add cold into the mix
until the desired temperature is reached.
NOTE: When using an "on/off" button on a showerhead or an outside wash down box, always
turn off the hot and cold water valves when finished. Not doing so will result in cold water
bleeding into the hot water system. This will either cause the water heater not to ignite or
result in alternating warm and cold water.
Dry Camping
RV showerheads are designed to drip when turned off and will allow the hot water line to be
filled with cold water. When showering it is recommended that you leave the water running
as you would at home. You will not run out of hot water and you will not waste additional
water waiting for the cold water to purge from the water line every time the water is turned
back on.
Winter Operation
When operating the 550-EC in cold climate conditions the flow of water may have to be
slightly restricted or slowed at the faucet to maintain the set temperature of 120 degrees.
NOTE: Your 550-EC is quipp d with th Cold W ath r Prot ction Packag . 12vdc pow r
and propan must b l ft on to prot ct th 550-EC from fr zing in cold climat conditions.
Wint r Driving Instructions: Und r no circumstanc s should you trav l in fr zing
conditions without first draining wat r from th unit. Follow the winter driving draining
instructions prior to driving in freezing temperatures. Freezing is not covered under the
product warranty
6.

550-EC Wat r H at r
Wint r Driving Draining Instructions
1. Turn off wat r supply.
2. Op n all hot wat r fauc ts.
3. R mov th 550-EC door and op n th Pr ssur R li f Valv by moving th l v r to
th op n position.
4. Th wat r lin s and th 550-EC will now drain.
5. Wh n all wat r is drain d from th hot wat r lin s and th 550-EC Flowm t r is
mpty r install th wat r h at r door. L av th Pr ssur R li f Valv and hot wat r
fauc ts op n whil driving.
6. Th h at r is now saf to driv in fr zing t mp ratur s.
7. Onc your d stination is r ach d clos th 550-EC Pr ssur R li f Valv . Turn on
wat r supply and clos all hot wat r fauc ts onc air is purg d from th lin s.
7.

Routine Maintenance
All faucet aerators and showerhead screens should be cleaned regularly. It is recommended
that the 550-EC be inspected by a qualified service technician at least once a year.
Particular attention should be paid to the following:
1. Inspect the air inlet openings and flue area to be clear of any debris or obstructions, (leaves,
bug nests, spider webs, etc.)
2. Check that the heater mounting is secure to the coach and there are no areas for potential
water leaks.
3. Open the cover of the heater and inspect for debris or obstructions under the burner or in
flue hood.
4. Visually inspect wiring. Be sure there is no chafing of the insulation. Be sure that the direct
spark ignition cable (black) wire is secured to the spark probe located at the lower right heat
exchanger area.
5. Check for soot around the flue. Soot is a sign of incomplete combustion. If you find soot a
qualified service technician should be notified to correct the problem.
6. The pressure relief valve should be manually activated once a year by moving the lever on
the top of the valve 90°while power is turned off. Never perform this operation while the
burner is operating or scalding could occur. Never plug the pressure relief valve. If the valve is
actuating too frequently contact PrecisionTemp or replace valve.
7. Unplug all connectors and reconnect with power turned off. Inspect and clean corrosion
from the ignition cable/spark probe connection and the ground wire connection.
NOTE: Should overheating occur or the gas supply fails to shut off, turn off gas valve at the
supply tank. Immediately call a qualified service technician
WARNING: Always turn off th 12-volt pow r supply to th h at r whil th v hicl is
moving and during any fu ling op rations. Op rating this wat r h at r or any oth r ignition
sourc during fu ling could caus a fir or xplosion, which could r sult in s rious injury or
d ath. Trying to produce hot water while driving or moving may damage the 550-EC
l ctrical compon nts and caus a fir .
8.

IMPORTANT COLD WEATHER PROTECTION INFORMATION
WARNING: Do not disconn ct th l ctrical supply or turn off th propan
supply wh n t mp ratur s ar n ar or b low fr zing. Th 550-EC fr z
prot ction syst m will not work if th l ctrical pow r sourc or propan is
disconn ct d. Your h at r is quipp d with th cold w ath r prot ction
packag (call Pr cisionT mp for d tails).
WARNING: Und r no circumstanc s should you trav l during
fr zing conditions without first draining wat r from th 550-EC.
WINTERIZING
Draining
1. Turn off th pow r and gas supply to th 550-EC.
2. Turn off main wat r supply.
3. Op n all hot wat r taps. (bathroom, kitch n, laundry, tc.)
4. Drain all wat r from plumbing lin s.
5. Op n pr ssur r li f valv to drain r maining wat r from
th 550-EC flowm t r and h at xchang r.
6. Aft r compl t ly draining th wat r syst m th h at r can b wint riz d
lik any other RV by purging remaining water out of water lines.
DO NOT vacuat h at r using compr ss d air, l t th h at r gravity drain by
op ning th Pr ssur R li f Valv , onc compl t d l av th valv in th op n
position. Th oth r m thod is to pump RV antifr z solution through th hot
and cold wat r syst m; no bypass valv is r quir d.
Pr cisionT mp
3428 Hauck Rd. Suit G
Cincinnati, Ohio 45241
513-641-4446
800-934-9690
s rvic @pr cisiont mp.com
3/2023
9.

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TROUBLESHOOTING
Most problems are easily remedied by consulting
the trouble-shooting guide. If problems still persist,
contact PrecisionTemp or an authorized service
center. Only a qualified technician should do any
work involving the gas system.
A periodic visual check of the burner flames should
be done by observing the flame through the opening
in the heat exchanger. There should be blue flame
with minimum or no yellow tipping. There should be
nothing obstructing the flow of combustion and
ventilation air.
Burner maintenance should be performed by a
PrecisionTemp Authorized Service Technician.
NOTE: The heater is dormant until it senses
water flow. When a water tap is turned on to at
least .5 GPM the burner will fire until water flow
is turned off and the heater again goes dormant.
Heater Does Not Come On When The Water is
turned on. (Power vent not running)
1. Be sure power is on and panel breaker is not
tripped.
2. Check electrical contacts. Be sure the connector
is plugged into board. Using a voltmeter, check for
12Volts on this connector.
3. Be sure all electrical connectors are secure and
the polarity is correct. (Red wire to positive terminal).
4. Fuse in power wire might be blown. Replace
fuse.
5. Locate the ECO, high temperature switch (red
and purple wires) at the upper left hand of the heat
exchanger. Check for open circuit condition. The
ECO should be reset by pushing the reset button
when temperature drops below 160 degrees.
6. Be sure there is a battery in the system. Never
connect the heater directly to a power converter.
Some converters have circuits that are not pure DC.
This can cause malfunctions or damage to the
heater and is not covered by warranty.
7. Be sure that no water-mixing valve has been left
in the on position, using the showerhead as a shut
off. This will permit water to bypass the water heater
and bleed cold water into the hot water system.
Always turn off both hot and cold water valves after
using.
8. Be sure that the bypass valve at the water
plumbing connections is in the "off" position. An
open valve can also permit water to bypass heater,
causing it not to fire.
There Is No Ignition When Water Is On (Power
vent is running)
1. Be sure the gas valve at the tank is “On”, there is
gas in the tank and the gas line is purged of all air.
2. Be sure that water flow is at least .5 gallon per
minute.
3. Check that the ignition wire is plugged into the
spark tower on the ignition control and is not touching
anything else.
4. Check flame site hole to see if igniter is sparking
from the probe to the burner. Contact PrecisionTemp
or your nearest authorized service representative.
5. Check that there are no cuts or breaks in the wire.
Align it so that it is not in contact with anything but the
terminal.
6. Be sure that the power vent fan has 12 volts to it
when there is water flowing and there are no
obstructions in the flue pipe.
7. Safety pressure switch may be out of adjustment.
Contact PrecisionTemp or your nearest authorized
service representative.
No Water Flows From Tap When Tap is Turned
on.
Be sure that water supply is turned on and that there
are no obstructions.
Burner Turns On But Temperature Fluctuates
Erratically.
1. May be caused by excessive restriction at the
water outlets, showerheads, aerators or water
strainers. These should be cleaned and any
showerhead flow restrictor removed.
2. If temperature fluctuates as the pump cycles, a
pressure accumulator tank is needed in the water
system. If you have an accumulator tank, check to
see if it has become filled with water. If it has, drain it
so that it contains air only.
Heater Comes On But Rapidly Cycles On And Off.
1. Water flow is too low. Increase flow at a tap. Clean
all aerators and shower head screens to assure at
least .5 GPM of water flow
2. Water pump is not functioning properly. Repair or
replace pump.
3. If the heater cycles as the pump cycles, a pressure
accumulator tank is needed in the water system. If
you have an accumulator tank, check to see if it has
become filled with water. If it has, drain it so that it
contains air only.
4. Air is in the water line. Bleed air by turning on all
water taps.
5. Hot and cold water lines connected to heater are
reversed. Correct by reversing their positions.
10.

Burner Ignites But Water Temperature Is too low
1. The water flow may be so high as to exceed the
capacity of the heater particularly if your supply water
is very cold. Slow the water flow.
2. The gas pressure may be too low. Be sure the
gas flow control valve is in full “on” position.
3. Check the gas pressure while the water is on at
full flow. The LPG pressure should be the “manifold
pressure” as shown on the specification label while
the heater is running. A gas-testing gauge should be
installed on the manifold tap so that it may be read
while heater is running. If it is too low, turn up the gas
regulator to the proper pressure. This should only be
done by a qualified technician.
4. The gas flow may be too low due to improper gas
line diameter (under 3/8 inch outside diameter). The
gas line may be excessively long (over 20-30 feet) or
the on/off solenoid at the tank (if you have one) may
have an orifice that is too small (under 3/16th of an
inch).
5. Check the heater door louvers and flue pipe for
airflow obstructions and clean.
6. Check that the “summer / winter” valve is in the
proper position for the temperature of the incoming
water.
Water Temperature Is Too Hot or No Temperature
Control.
1. Fuel tank regulator is set too high and manifold
pressure as described above Have the regulator
checked by a qualified technician.
2. Water flow too low for incoming water
temperature.
Low Heat Rise and Excessive Water Flow Is
Required To Trigger Water Heater
If you find that your heater requires excessive flow to
activate it (much over .5 gallon per minute), it is likely
that you have cold water bleeding into the hot water
side of your water system.
1. Check that valves and faucets are closed when
not in use. If there is an on/off button on your
showerhead, always turn the water valves off after
the shower to prevent cold water from bleeding into
the hot water system. This will keep the heater from
functioning properly.
2. Be sure that the bypass valve at the water plumbing
connections is in the "off" position. An open valve can
also permit water to bypass heater, causing it not to fire.
PrecisionTemp,
Inc.WATER HEATER
LIMITED WARRANTY
PrecisionTemp, Inc warrants to the original owner and subject
to the below mentioned conditions, that this product will be free
of defects in material or workmanship for a period of two years
from the original date of purchase. PrecisionTemp’s liability
hereunder is limited to the replacement of the product, repair of
the product, or replacement of the product with a reconditioned
product at the discretion of the manufacturer. This warranty is
void if the product has been damaged by accident,
unreasonable use, neglect, tampering or other causes not
arising from defects in material workmanship. This warranty
extends to the original owner of the product only and is subject
to the following conditions:
1. For two years from the date of purchase, PrecisionTemp will repair
or replace any part defective in material or workmanship. Some
warranty parts may require a prepay before shipping. Once the
defective part is returned and tested the prepay charge may be
refunded based on findings.
2. This warranty includes labor charges pre-authorized by
PrecisionTemp required to remove and replace the part.
3. Service/Travel calls to the customers location are not considered
part of these charges and are therefore the responsibility of the
owners.
4. This warranty does not cover the following items classified as
normal maintenance:
a. adjustment of gas pressure
b. cleaning or replacement of burner orifices
c. cleaning or adjustment of burner assembly
d. cleaning or adjustment of flue
e. adjustment of pressure relief valve
5. In the event of a warranty claim, the owner must contact, in
advance PrecisionTemp, Inc 800-934-9690 Ext.110.
Return parts (or water heater) must be shipped to PrecisionTemp
“Prepaid”. The defective parts (or water heater) become the
property of PrecisionTemp and must be returned to the Service
Department at PrecisionTemp
6. This warranty applies only if the unit is installed according to the
installation instructions provided and complies with local and state
codes.
7. The warranty period on replacement parts (or water heater) is the
unused portion of the original warranty period or ninety (90) days,
whichever is greater.
8. Damage or failure resulting from misuse (including failure to seek
proper repair service), misapplication, alterations, water damage,
or freezing are the owner’s responsibility.
9. PrecisionTemp does not assume responsibility for any loss of use
of vehicle, loss of time, inconvenience, expense for gasoline,
telephone, travel, lodging, loss or damage to personal property or
revenues. Some states do not allow the exclusion or limitation of
incidental or consequential damages, so the above limitations or
exclusions may not apply to you.
10. Any implied warranties are limited to two (2) years. Some
states do not allow limitations on how long an implied warranty
lasts, so the above limitation may not apply to you. This warranty
gives you specific legal rights and you may also have other rights
which vary from state to state.
Replacement parts purchased outside of the original water heater
warranty carry a 90 day warranty.
11. This PrecisionTemp heater is designed for use in recreational
vehicles, park models, tiny homes, mobile food carts and marine
applications for the purpose of heating water as stated in the “data
plate” attached to the water heater. Any other use, unless
authorized in writing by the PrecisionTemp Engineering
Department, voids this warranty.
PrecisionTemp Inc.
3428 Hauck Rd. Ste. G
Cincinnati, OH. 45241
Phone: [phone] * 800-934-9690 Fax: [phone]
www.precisiontemp.com
11.