A.O. Smith FMD 40 Water Heater User Manual


 
26
TROUBLESHOOTING GUIDELINES
These guidelines should be utilized by a quali ed service agent.
Problem Cause Solution
Improperly sealed, hot or cold supply connection, Tighten threaded connections.
relief valve, drain valve, or thermostat threads.
Leakage from other appliances or water lines. Inspect other appliances near water heater.
Condensation of ue products. Refer to CONDENSATION.
Thermal expansion in closed water system. Install thermal expansion tank (DO NOT plug T&P valve).
Improperly seated valve. Check relief valve for proper operation
(DO NOT plug T&P valve).
High sulfate or mineral content in water supply. Drain and ush heater thoroughly, then re ll.
Bacteria in water supply. Chlorinate or aerate water supply.
Dirty pilot burner. Clean pilot assembly.
Thermocouple tip is not in contact with pilot ame. Insert thermocouple correctly.
Thermocouple malfunction. Replace thermocouple.
Thermocouple malfunction. Check thermostat.
Gas knob dial not positioned correctly. Refer to LIGHTING INSTRUCTIONS.
Pilot ori ce clogged. Clean or replace pilot ori ce.
Pinched or clogged pilot tube. Replace pilot tube.
Main gas supply off. Turn on main gas shut-off valve.
Heater not lit or thermostat not on. Refer to LIGHTING INSTRUCTIONS.
Thermostat set too low. Refer to TEMPERATURE REGULATION.
Heater undersized. Reduce the hot water use.
Low gas pressure. Contact dealer.
Incoming water is unusually cold. Allow more time for heater to re-heat.
Leaking hot water pipes or xtures. Have a plumber check and repair leaks.
High temperature limit switch activated. Contact a Service Agency to determine cause.
Thermostat set too high. Refer to HIGH TEMPERATURE REGULATION.
Condensate dripping on burner. Refer to CONDENSATE.
Sediment at bottom of heater tank. Clean sediment from tank. Refer to DRAINING instructions
in Maintenance section of manual.
Improper combustion. Refer to FACTS TO CONSIDER ABOUT THE LOCATION.
Also see Figure 2 on page 6.
WATER LEAKS
LEAKING T&P VALVE
HOT WATER ODORS
PILOT OUTAGE
PILOT WILL NOT LIGHT
NOT ENOUGH OR
NO HOT WATER
WATER TOO HOT
WATER HEATER SOUNDS:
SIZZLING - RUMBLING
SOOTING