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17

TROUBLESHOOTING

For your safety, water heater service should be performed only by a qualified service technician.

Read the GENERAL SAFETY INFORMATION section first.

  WARNING: DO NOT BY-PASS ANY CONTROLS TO MAKE HEATER OPERATE. OPERATE ONLY AS WIRED FROM FACTORY.

1) Blower will not run

A ) “ON/OFF” control switch turned off
B) Blower unplugged
C) No power at outlet
D) “ON/OFF” switch defective
E)

Control harness defective

F)

Blower motor defective

2) Blower running, burner not on

A ) Fan not running fast enough to close

air switch contacts

B) Air pressure switch defective
C) Gas valve defective
D) Control harness defective
E)

Igniter defective

F)

Unit has completed three trials to light
and failed

G) Discharge air limit tripped

3) Thermostat problems

A ) Thermostat set too low
B) Thermostat or ECO defective
C) High limit control circuit open

4) Others

A ) Heater undersized
B) Low gas pressure
C) Incoming water is unusually cold
D) Leaking hot water pipes or fixtures
E)

Polarity reversed

F)

Heater not grounded

A ) Blower does not run when heater fired

B) Not enough dilution air to mix with flue

 gases in “Tee”

C) Air in room too hot for mixing with flue gases

D) Wrong burner orifice
A ) Dirt in burner ports
B) Combustion air path restricted

C) Not enough room air for proper combustion

A ) Water on the floor under heater

Improperly sealed, hot or cold supply connections,
relief valve, drain valve or thermostat threads
Leakage from other appliances or water lines
Condensation of flue products
Thermal expansion in closed water system
Improperly seated valve
High sulfate or mineral content in water supply or
iron or sulfate reducing bacteria in water supply
Outlet polarity is reversed

PROBLEM

POSSIBLE MALFUNCTION

        SERVICE TO BE PERFORMED

NOT ENOUGH OR

NO HOT WATER

VENT PIPE TOO HOT

(ABOVE 170° F)

YELLOW FLAME

CONDENSATION

WATER LEAKS

LEAKING T&P VALVE

HOT  WATER  ODORS  OR  COLOR

(Refer to CATHODIC PROTECTION)

HEATER LIGHT GOES OUT

IN 4-5 SECONDS

Turn switch to the “ON” position.
Plug blower back into 115 vac. outlet.
Repair service to outlet.
Replace switch.
Replace control harness.
Replace blower and motor.
Replace switch.
Check for low voltage, less than 102 vac., have service
checked and repaired.
If voltage is above 102 vac., make sure there is not more than
30 Equivalent feet of 3 inch pipe or85 equivalent feet of 4 inch
pipe installed or vent terminal blockage.
If at least 102 vac., less than 30 equivalent feet of 3 inch pipe
or 85 equivalent feet of 4 inch pipe and not terminal blockage,
replace blower.
Replace switch.
Replace gas valve.
Replace harness.
Replace igniter.
Reset cycle by turning switch off and then back on. If unit
does not light in three trials, call an authorized A.O. Smith
service representative.
Verify dilution air openings are free of obstructions.
Make sure there is no more than 30 equivalent feet of 3 inch pipe or
85 equivalent feet of 4 inch pipe.
Check for low voltage, less than 102 vac., have service
checked and repaired.
Make sure vent terminal is not blocked.

Turn temperature control higher.
Replace thermostat.
Replace.

Reduce hot water use.
Contact an authorized A.O. Smith service representative.
Allow more time for heater to re-heat.
Have plumber check and repair leaks.
Correct wiring
Correct
Take unit out of service immediately, call an authorized A.O.
Smith service representative.
Proper air circulation must be provided for combustion and
dilution of flue temp. Refer to “INSTALLATION” section.
Room air to be used for dilution with combustion products in
flue should be less than 90°F.
Install correct orifice.
Turn off heater and gas, clean burner head.
Clear area around heater and check under heater, remove
any debris under heater and in openings in bottom cover.
Refer to installation manual - Confined and Unconfined Space
statements on page 4 and 5 for required openings.
See “CONDENSATION.”

Turn off heater & water, repair unit.

Inspect other appliances near water heater.
Refer to “CONDENSATION.”
Install thermal expansion tank (DO NOT plug T&P valve).
Check relief valve for proper operation (DO NOT plug T&P valve).
Drain and flush heater thoroughly, chlorinate, refill and flush
again then chlorinate water supply.
Test polarity and correct.

Summary of Contents for FPSH-75

Page 1: ...ing instructions as well as the WARNING and CAUTIONS CAUTION TEXT PRINTED OR OUTLINED IN RED CONTAINS INFORMATION RELATIVE TO YOUR SAFETY PLEASE READ THOROUGHLY BEFORE INSTALLING AND USING THIS APPLIANCE RESIDENTIAL GAS WATER HEATERS OWNER S MANUAL ADIVISION OFA O SMITH CORPORATION www hotwater com GET TO KNOWYOUR WATER HEATER 2 GENERAL SAFETY INFORMATION 3 4 INSTALLATION 4 12 OPERATION 12 14 MAIN...

Page 2: ...ased locally FPSH 75 with Hot Surface Ignition GET TO KNOW YOUR WATER HEATER A VENT PIPE B ANODE C HOT WATER OUTLET D OUTLET 120 VAC E FLUE BAFFLE F GASSUPPLY G MAINMANUALGAS SHUT OFF VALVE H GROUND JOINT UNION J DIRT LEG K OUTER DOOR L UNION M INLET WATER SHUT OFF VALVE N COLD WATER INLET O INLET DIP TUBE P TEMPERATUREAND PRESSURE RELIEF VALVE Q EMBLEMANDRATINGPLATE R INSULATION S VENT TERMINAL T...

Page 3: ... cause yourself Go to a neighbor s house leaving your doors open to ventilate the house then call your gas supplier or service agent Keep area clear until a service call has been made At times you may not be able to smell an LP gas leak One cause is odor fade which is a loss of the chemical odorant that gives LP gas its distinctive smell Another cause can be your physical condition such as having ...

Page 4: ...closet having minimum clearances from combustible material of 0 clearance from sides and rear 5 from the front and 12 from the top Standard clearance If clearances stated on the heater differ from standard clearances install water heater according to clearances stated on heater A minimum clearance of 4 must be allowed for access to replaceable parts such as the thermostats drain valve and relief v...

Page 5: ...e must be installed Please refer to Figure 2 for suggested piping arrangement FIGURE2 CLOSED WATER SYSTEM A closed system will exist if a back flow preventer check valve pressure reducing valve or other similar device is installed in the cold water line between the water heater and the street main or well Excessive pressure may develop due to the thermal expansion of heated water causing premature...

Page 6: ... manual or on water heater With main burner in operation paint pipe joints including flanges pilot gas tubing connections and control inlet and outlet with rich soap and water solution Bubbles indicate gas leak To stop leak tighten flange screws joints and pipe connections Replace part if leak can t be stopped DISCONNECT THE APPLIANCE AND ITS INDIVIDUAL SHUT OFF VALVE FROM THE GAS SUPPLY PIPING SY...

Page 7: ...erving power vented appliances are classified by building codes as vent connectors Required clearances from combustible materials must be provided in accordance with information in this manual under LOCATION OF HEATER and INSTALLATION OF VENT SYSTEM and with the National Fuel Gas Code and local codes PLANNING THE VENT SYSTEM Plan the route of the vent system from the discharge of the blower to the...

Page 8: ...nt terminal by using the cover plate as a template to mark the hole for the vent pipe to pass through the wall BEWARE OF CONCEALED WIRING AND PIPING INSIDE THE WALL 2 If the Vent Terminal is being installed on the outside of a finished wall it may be easier to mark both the inside and outside wall Align the holes by drilling a hole through the center of the template from the inside through to the ...

Page 9: ...sure E Splice field wiring into existing wiring using code authorized method wire nuts etc F Be certain that neutral and line connections are not reversed when making these connections G Ground heater properly This water heater must be grounded on accordance with the National Electric Code ANSI NPA70 and or local codes These must be followed in all cases The water heater must be connected to a gro...

Page 10: ...be supported every 5 feet of vertical run and every 3 feet of horizontal run All piping and fittings must be joined by the proper procedures as described under VENT PIPE PREPARATION FIGURE9 IMPORTANT The vent system must terminate so that proper clearances are maintained as cited in local codes or the latest edition of the National Fuel Gas Code ANSI Z223 1 and as listed below 1 Vent Termination m...

Page 11: ... type of cutter is used the flare on the end must be completely removed STEP A NOTE Power saws should be specifically designed to cut plastic pipe B Deburring Use a knife plastic pipe deburring tool or file to remove burrs from the end of small diameter pipe Be sure to remove all burrs from around the inside as well as the outside of the pipe A slight chamfer bevel of about 10 15 should be added t...

Page 12: ...uld not be disturbed immediately after the cementing procedure and sufficient time should be allowed for proper curing of the joint Exact drying time is difficult to predict because it depends on variables such as temperature humidity and cement integrity For more specific information you should contact your solvent cement manufacturer STEPG OPERATION WARNING DO NOTATTEMPTTO OPERATE WATER HEATER W...

Page 13: ...a fire or 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 part of the control system and any gas control which has been under water OPERATINGINSTRUCTIONS 1 STOP Read the safety information above on this label 2 Set the thermostat to the lowest setting 3 Turn the ON OFF switch on the b...

Page 14: ...exceed the thermostat setting by up to 30 F If you experience this type of use you should consider using lower temperature settings to reduce scald hazards Valves for reducing the point of use temperature by mixing cold and hot water are available see Figure 2 Also available are inexpensive devices that attach to faucets to limit hot water temperatures Contact a licensed plumber or the local plumb...

Page 15: ...NG THE DRAFT Operate the water heater for several minutes and check to see if it is venting properly by passing a lit match or paper near the opening of the Air Mixing Box see Figure 11 If the draft is proper the match flame will be drawn into the Air Mixing Box If not the combustion products will tend to extinguish the flame If an improper draft exists do not operate the water heater until proper...

Page 16: ... heater requires no special care other than the normal maintenance as noted above If you are having a problem with your water heater before calling for service please refer to the following TROUBLESHOOTING sections If service becomes necessary contact your dealer installer or an authorized service agent Do not attempt to repair the water heater yourself Any work performed by unauthorized personnel...

Page 17: ...into 115 vac outlet Repair service to outlet Replace switch Replace control harness Replace blower and motor Replace switch Check for low voltage less than 102 vac have service checked and repaired If voltage is above 102 vac make sure there is not more than 30 Equivalent feet of 3 inch pipe or85 equivalent feet of 4 inch pipe installed or vent terminal blockage If at least 102 vac less than 30 eq...

Page 18: ...e water heater off for 10 seconds and then back on 2 Replace gas control valve Problem with the internal circuit 1 Turn power to the water heater off for 10 seconds and then back on 2 Replace gas control valve Problem with the internal circuit 1 Turn power to the water heater off for 10 seconds and then back on 2 Replace gas control valve Flame signal sensed out of 1 Replace gas control valve prop...

Page 19: ...rnish the ORIGINAL OWNER a replacement A O Smith water heater of equivalent size and current model or a replacement part for any component part which fails in normal use in accordance with the warranty terms and conditions specified below THE A O SMITH REPLACEMENT MODEL OR PART WILL BE WARRANTED FOR ONLYTHE UNEXPIRED PORTION OFTHE ORIGINAL WARRANTY The warranty period will be determined by the ori...

Page 20: ...20 A O SMITH WATER PRODUCTS CO INC 5621 W 115TH STREET ALSIP ILLINOIS 60803 PHONE 1 800 433 2545 FAX 1 800 433 2515 www hotwater com E MAIL parts hotwater com ...

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