Things You'll Need
Honeywell SmartValve system controls provide intermittent pilot gas ignition sequencing. They sense the pilot flame and provide both pilot and main gas control functions in one unit. They are used in many types of gas-fired heating appliances like central furnaces, residential boilers, cooking appliances for commercial applications and heaters. Troubleshooting them is a bit complicated and involves some technical knowledge and referral to the instruction manual.
Turn off the gas supply. Make sure the SmartValve switch is in the "On" position. Disconnect the system control harness and set the thermostat to "Heat.".
Makes sure the element is good. Disconnect the element from the Honeywell SmartValve and make sure the element room temperature resistance is less than 10 ohms.
Make sure the switch or knob on the SmartValve is on.
Make sure the call to heat function on the appliance is compatible with the SmartValve. Measure it with a voltmeter. Check the manual for voltage requirements.
Check the line power, transformer, switches, thermostat and wiring. Check that the vent damper is open.
Check for the proper voltage at the control. The voltage should be 24V between the thermostat or pressure switch and 24V Common, and 24V between the 24V Common and 24V Hot.
Plug the harness into the SmartValve and wait for the internal check delay. Wait for the repurge. The igniter should warm up and glow red. If it does, turn everything back on. If it doesn't glow red, with the pilot burner cable connected, measure the voltage at the SmartValve element output. 24V is normal. Replace the SmartValve if you don't get 24V. If you do get 24V, simply replace the igniter/flame rod assembly.
Check if gas is flowing if you turn on the gas and the pilot burner doesn't light. If it isn't flowing, replace the SmartValve. If it is flowing, measure the voltage between the 24V Hot and 24V Common leads to the SmartValve. It must measure at least 19.5VAC with the igniter powered. If it is, simply replace the igniter/flame rod assembly. If it isn't, check the transformer and line volt supply.
Check that the pilot flame makes good contact with the pilot burner flame rod and check for good electrical connections through the pilot tubing if you have the main valve open and the main burner doesn't light. Cycle the thermostat off and back on. The main burner should light. If it doesn't, replace the SmartValve.
Patrick Nelson has been a professional writer since 1992. He was editor and publisher of the music industry trade publication "Producer Report" and has written for a number of technology blogs. Nelson studied design at Hornsey Art School.