A.O. Smith GB/GW-500 Error Message Reported Error, Blocked Vent SHUT-OFF System, Burner System

Troubleshooting

The WHC1502 Series Control System has many inherent diagnos- tic and fault detection routines built into its operating hardware and software. These routines, in conjunction with the four (4) digit LED display and eleven (11) LED status indicators on the Display Board, can greatly assist any service person in quickly pinpointing the source of a problem which may occur within the appliance. Under certain circumstances, multiple LED’s will illuminate to better pinpoint the target area(s).

The following list defines the error code messages that scroll across the LED display:

ERROR MESSAGE	REPORTED ERROR
OPEn InLEt ProbE	No probe detected at connec-
	tor CN1 on Control Board.
OPEn OutLEt ProbE	No probe detected at connec-
	tor CN2 on Control Board.
Circulation FAIL	No flow detected at flow
	switch.
Inducor FAIL	No pressure detected at pres-
	sure switch.
FLAmE SenSE FAIL	Flame sense detected before
	gas valve is turned on.
SenSor FAIL	One of the sensors, Flow,
	Pressure, Hi Gas, or Lo Gas
	was not in the correct state.
Ignitor FAIL	No Ignitor current sensed.
No Ignition	Flame not detected after 1 or
	3 tries.
ECO FAIL	ECO/High Limit switch
	opened.
Control FAIL	Relay did not open or close
	properly.

BLOCKED VENT SHUT-OFF SYSTEM

surrounding air pressure. Inspection of the boiler and vent system is necessary to insure that flue gas leakage to the surrounding area does not occur.

Inspect the external surfaces of the vent system every 3 months for corrosion and leakage. Inspect the vent terminations for corrosion and foreign matter which may be blocking the exhausting flue products. Call a qualified service agent to replace or repair any corroded or leaking parts.

Qualified service agent must inspect internal surfaces of the vent system and the boiler at least once a year.

BURNER SYSTEM

To maintain safe operation and the greatest efficiency for the boiler, observe the burner flame through the observation port on the left jacket panel, once a month for proper flame characteristics.

The burners should display the following characteristics:

•Provide complete combustion of gas.

•Cause rapid ignition and carry over across all burners and across the entire burner.

•Give quiet operation during ignition, burning and extinction.

•Cause no excessive lifting of flames from the burner ports.

If the preceding characteristics are not evident, check for accumulation of lint or other foreign material that restricts the inlet air or burner ports. Ensure there is the proper amount of air to the burner. Flame lifting from the burner is caused by too much air to the burner.

The burners must be inspected by a qualified service technician at least once a year.

DO NOT STORE COMBUSTIBLE MATERIALS, GASOLINE, OR OTHER FLAMMABLE VAPORS, LIQUIDS IN THE AREA OF THE APPLIANCE. NONCOMPLIANCE MAY RESULT IN FIRE OR EXPLOSION. DO NOT OBSTRUCT THE FLOW OF COM- BUSTION OR VENTILATION AIR TO THE APPLIANCE.

CHEMICAL VAPOR CORROSION

The Boiler is equipped with a blocked vent shut-off system which will close the gas valve and shut off the main burner gas when there is excessive pressure in the vent system due to a partially or completely blocked vent system. The DIA-SCAN II display on the front panel will indicate this failure condition.

DO NOT ATTEMPT TO OPERATE THE BOILER if this situation occurs. Shut the boiler off before performing all the steps shown in "TO TURN OFF GAS TO APPLIANCE" section of the Lighting and Operating Instructions.

Contact a qualified service agent to inspect the unit and vent system and correct the problem.

VENT SYSTEM

The flue products are corrosive in nature and if the boiler is vented horizontally the flue gases are at a higher pressure than the

Boiler corrosion and component failure can be caused by airborne chemical vapors. Spray can propellants, cleaning solvents, refrigerants, calcium or sodium chloride (water softener salts), waxes, and process chemicals are typical compounds that are potentially corrosive. These materials are corrosive at very low concentration levels with little or no odor to reveal their presence. Products of this sort should not be stored near the boiler. Air which is brought in contact with the boiler should not contain any of these chemicals. The boiler should be provided with air from outdoors when installed in environments having corrosive atmospheres.

CIRCULATION PUMP

Refer to the pump manufacturer's schedule of maintenance for frequency and method of lubricating the pump and motor. Inspect the pump once a month for leaky mechanical seals and/or O-rings and loose or damaged components. Contact a qualified service agent to replace or repair parts as required.

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