A.O. Smith BTH 120-250(A) warranty Checklist and Service Information, Trouble-Shooting

CHECKLIST AND SERVICE INFORMATION

IMPORTANT

The installer may be able to observe and correct certain problems which might arise when the unit is put into operation or when it is re-fired after a prolonged shutdown. HOWEVER, it is recommended that only qualified servicemen, using appropriate test equipment, be allowed to service the heater.

BE SURE TO TURN OFF THE ELECTRICITY WHENEVER POSSIBLE OR APPROPRIATE WHILE CHECKING EQUIPMENT.

WARNING

FAILURE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN SERIOUS PERSONAL INJURY OR DEATH.

CAUTION: LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN SERVICING CONTROLS. WIRING ERRORS CAN CAUSE IMPROPER AND DANGEROUS OPERATION.

VERIFY PROPER OPERATION AFTER SERVICING.

BURNER OPERATIONAL PROBLEMS

1. Refer to TROUBLESHOOTING.

NOT ENOUGH OR NO HOT WATER

1.Be certain the electrical disconnect switch serving the water heater is in the ON position.

2.Check the fuses.

•The electrical disconnect switch usually contains fuses.

3.The capacity of the heater may have been exceeded by a large demand for hot water.

•Large demands require a recovery period to restore water temperature.

4.Colder incoming water temperature will lengthen the time required to heat water to the desired temperature.

•If the heater was installed when incoming water temperature was warm, colder water creates the effect of less hot water.

5.Look for hot water wastage and leaking or open hot water faucets.

6.Sediment or lime scale may be affecting water heater operation. Refer to MAINTENANCE for details.

7.The heater’s temperature high limit sensor has activated. Press the reset button on the thermostat.

8.Burner may not be firing at proper rate.

•Check gas pressure. Adjust to obtain required manifold pressure.

9.Burner fan wheel may be dirty.

•Clean fan wheel with a stiff brush.

10.Condensate hose may be blocked where it connects to the exhaust elbow.

•Verify the condensate drains from the unit without restriction.

WATER IS TOO HOT

1. Refer to WATER TEMPERATURE CONTROL.

WATER HEATER MAKES SOUNDS

1.Sediment or lime scale accumulations cause rumbling and pounding noises when the heater is operating.

•The sounds are normal, however, the tank bottom should be cleaned. Refer to MAINTENANCE for details.

2.Some of the electrical components of the water heater make sounds which are normal.

•Contacts click or snap as the heater starts and stops.

•Transformers often hum.

WATER LEAKAGE IS SUSPECTED

1.Check to see if the water heater drain valve is tightly closed. Also check the cleanout opening for leakage.

2.The apparent leakage may be condensation which forms on cool surfaces of the heater and piping.

3.If the outlet of the relief valve is leaking it may represent:

•Excessive water pressure.

•Excessive water temperature.

•Faulty relief valve.

Excessive water pressure is the most common cause of relief valve leakage. It is often caused by a “closed system”. If a check valve is in the inlet system it will not permit the expanded hot water volume to equalize pressure with the main. The relief valve must release this water or the water heater or plumbing system will be damage d. Refer to MAINTENANCE- RELIEF VALVE section in this manual.

When such a condition is encountered, local codes or inspection agency should be consulted to determine which system is acceptable in your area. See CLOSED SYSTEM section in this manual also.

TROUBLE-SHOOTING

1.Verify that the allowable vent length has not been exceeded and that the blower inlet screen has been removed if direct venting.

2.Verify that the condensation, which WILL be present in the heater and exhaust vent, will drain.

3.Check supply wire polarity - hot to hot and neutral to neutral and no "stray" current in neutral.

4.Heater is properly grounded.

Checking these four (4) items first will often result in a timely solution to the service call.

WARNING

JUMPING OUT COMPONENTS AND/OR CIRCUITS DURING TROUBLESHOOTING CAN CAUSE SERIOUS PROBLEMS WITH THE UNIT’S OPERATING SEQUENCE AND IGNITION SAFETY. IF YOU DO NOT HAVE THE PROPER TEST EQUIPMENT, I.E. A VOLT-OHM METER AND A MICROAMMETER, DO NOT ATTEMPT TO TROUBLESHOOT OR REPAIR A.O. SMITH EQUIPMENT.

ALTERING THE CONTROLLER AND/OR CONTROLLER WIRING IN ANY WAY COULD RESULT IN INTERNAL DAMAGE TO THE MODULE CIRCUITS, POSSIBLY ALTERING THE IGNITION SEQUENCEALLOWING GAS VALVES TO OPEN BEFORE THE HOT SURFACE IGNITER IS UP TO IGNITION TEMPERATURE.

NOTE: ANY BYPASS OR ALTERATION OF THE UNITS SAFETIES WILL RESULT IN VOIDING THE APPLIANCE WARRANTY.

Before performing any troubleshooting familiarize yourself with the particular appliance.

Refer to the SEQUENCE OF OPERATION and the connection diagram located on page 15 before continuing.

Make sure the appliance is connected to a 120V AC power supply, manual gas valve is in the ON position, and all electrical connections are secure before continuing to troubleshoot this appliance.

CAUTION

THE WATER HEATER IS POLARITY SENSITIVE. BEFORE APPLYING ELECTRICITY TO THIS HEATER BE CERTAIN THAT SUPPLY HEATED WIRE TO GROUND CHECK INDICATES ZERO VOLTAGE.

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