A.O. Smith 225M, 200M Service Information, Pilot and Main Burner Maintenance, D. Pilot Burner

SERVICE INFORMATION

The installer may be able to observe and correct certain problems which may arise when the unit is put into operation. HOWEVER, it is recommended that only qualified service personnel, using appropriate test equipment, be allowed to service the heater.

Any safety devices used in conjunction with this appliance should receive periodic (at least twice a year) inspection to assure proper operation. All relief valves should be inspected and manually operated every six months.

PILOT AND MAIN BURNER MAINTENANCE

At least twice a year, check the pilot burner, fig. 15 and the main burners, fig 13, for proper operation.

The burners should display the following characteristics:

•Provide complete combustion of gas.

•Cause rapid ignition and carryover of flame across entire burner.

•Give reasonably quiet operation during ignition, burning and extinction.

•Cause no excessive lifting of flame from burner ports.

If the preceding burner characteristics are not evident, check for accumulation of lint or other foreign material that restricts or blocks the air openings to the burners or heater.

Also check for good flow of combustion and ventilating air to the unit. Maintain a clear area around the heater at all times.

Qualified servicers should follow this procedure when the heater’s burners need cleaning.

1.Turn off the electrical power and close the main manual gas shutoff valve.

• Allow heater parts to cool before disassembly.

2.Remove main burner manifold assembly from heater.

•Refer to parts list supplied with this manual for disassembly aid.

3.Remove any loose foreign material such as dust or lint with a vacuum. Check all ports, orifices and air openings for blockage. Dislodge any foreign material causing blockage. Do not use sharp metal objects to clean blocked orifices as they will damage the soft brass orifice. Remove any soot or carbon deposits with a rag making sure to remove any lint left on burner by vacuuming again.

MAIN BURNER FOR HW HEATERS

FIGURE 13

4. Reinstall the burner manifold assembly on heater.

5. Restore electrical power and gas supply to heater.

•Check for gas leaks and proper heater and vent operation.

I.I.D. PILOT BURNER

Servicing of the pilot burner includes cleaning the burner head and the orifice of the pilot burner, fig. 15.

The pilot flame should envelop 3/8 to 1/2 in. of the tip of the insulated rod on the igniter-sensor. If adjustment is required, it is necessary to establish pilot flame without main burner operation. For this to happen, perform the following steps.

1.Follow “TO TURN OFF GAS TO APPLIANCE” steps in the

“OPERATING INSTRUCTIONS FOR I.I.D. MODELS”.

2.Carefully disconnect the wire terminal connected to the MV terminal of the S8600 module, fig. 3.

3.Turn gas valve control knob counterclockwise to “ON”.

4.Turn on all electric power to the heater.

5.Set tank temperature control to call for heat. Pilot will operate without the main burners igniting.

6.Remove the pilot adjustment cover screw, fig. 14, and turn the

inner adjustment screw clockwise to decrease or counterclockwise to increase the pilot flame. Be sure to replace cover screw after adjustment to prevent possible gas leakage.

7.Repeat step 1.

8.Carefully reconnect the MV wire terminal to the S8600 module. Be sure the terminal is securely connected.

9.Follow “OPERATING INSTRUCTIONS FOR I.I.D. MODELS” to put heater back into operation.

If the pilot burner ignites but the main burner fails to light, check for gas flow to the main burner.

Check for good terminal connections at the igniter-sensor connector (fig. 15) and at the S8600 module.

For further assistance see Chart 2, “S8600 INTERMITTENT PILOT SYSTEM TROUBLESHOOTING”.

HONEYWELL GAS VALVE FOR I.I.D. SYSTEM (TOP VIEW)

FIGURE 14

20