Troubleshooting - A.O. Smith Commercial gas water heaters Instruction Manual

proBleMs
not enouGh hot water
VENT PIPE TOO HOT (ABOVE 170°F [77°C])
Yellow flaMe
condensatIon
water leaKs
leaKInG t & p
hot water odors
(refer to cathodic protection)
hot water too hot
water heater sounds
SIZZLING - RUMBLING
sootInG
Burner wIll not staY lIt-Goes out
4-5 SECONDS
vent Gas odors
trouBleshootInG GuIdelInes
These guidelines should be utilized by a qualified service agent.
1.) Blower will not run.
a. "ON/OFF" control switch turned off.
b. Blower unplugged.
c. No power at outlet.
d. Thermostat defective.
e. Control harness defective.
f. High limit control circuit open.
g. Blower motor defective.
2.) Thermostat problems
a. Thermostat set too low.
b. Thermostat or ECO defective
3.) Others
a. Heater undersized..
b. Low gas pressure
c. Incoming water is usually cold.
d. Leaking hot water pipes of fixtures.
e. Heater not lit or thermostat not on.
Wrong burner orifice.
Dirt in burner ports.
Combustion air path restricted.
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 sealed valve.
High sulfate or mineral content in water
supply.
Bacteria in water supply.
Thermostat set too high.
Condensation dripping on burner.
Sediment at bottom of heater tank.
Improper combustion.
Outlet polarity is reversed.
High ambient room temperature.
Defective gas valve.
Lack of air supply.
Improperly installed vent piping.
Downdraft
Poor Combustion
Turn switch to the "ON" position.
Plug blower back into 115 VAC outlet.
Repair service to outlet.
Replace thermostat.
Replace control harness.
Reduce the water temperature below 140°F.
Turn the power switch to the off position.
Wait 10 seconds. Turn the power switch to
the on position. Reduce the temperature set
point to minimize likelihood of reoccurrence. If
this does not solve the problem, replace the
thermostat.
Replace blower assembly.
Adjust temperature control higher.
Replace thermostat.
Reduce hot water use.
Contact dealer.
Allow more time for heater to reheat.
Have plumber check and repair leaks.
Refer to LIGHTING INSTRUCTIONS.
Turn off heater and gas, clean burner head.
Turn off heater and gas, clean burner head.
Check exhaust venting and air openings
in bottom base pan for obstructions or
blockage.
See CONDENSATION section.
Check for leaks. See Figure 1.
Inspect other appliances near water heater.
Refer to CONDENSATION section.
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 then refill.
Chlorinate water supply.
Refer to TEMPERATURE REGULATION
section.
Refer to CONDENSATION above.
C l e a n s e d i m e n t f r o m t a n k . R e f e r t o
DRAINING.
Refer to Air Requirements.
Test polarity and correct.
Contact a qualified service agency to
determine cause.
Replace gas valve.
Shut off water heater immediately and contact a
qualified service agency to determine cause.
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