300-1 – Commercial Gas Water Heater with Damper


Honeywell Temperature Control System

Troubleshooting Guide
Sequence of Operation

1) Thermostat calls for heat.
2) Thermostat supplies 24 volts to damper.
3) Damper opens supplying 24 volts to the ignition module.
4) Ignition control module sends 24 volts to the pilot valve allowing gas to flow to pilot. Simultaneously, the ignition control module sends high voltage low current electricity through the electrode wire to pilot electrode causing sparking at the pilot assembly. (If the pilot fails to ignite within 90 seconds, the ignition control stops the pilot gas as well as the sparking for 15 seconds to allow gas to dissipate. The ignition control will then attempt two (2) more ignition trials.)
5) Once the pilot is lit, it is then recognized by the sensor in the pilot assembly and sends a signal back to the module acknowledging the pilot flame. The sparking stops, 24 volts is sent to the main gas valve to open.
6) The main burner fires until the thermostat is satisfied. The 24-volt circuit is then interrupted to the gas valve, closing both the main and pilot valves. The damper closes, the thermostat monitors the tank awaiting a call for heat.

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