False flame signal – The boiler will lock out if it senses a flame signal when there should be none present.
- Look into window. If there is flame, turn the gas off to the unit at the service valve and replace gas valve.
- If the flame signal is present and there is no flame, replace the flame rectification probe.
- If the flame signal is not present after turning off the gas supply, check the gas valve electrical connection.
- Remove the gas valve and check for obstruction in the valve seat or replace the gas valve.
- Turn the gas on at the service valve after corrective action is taken.
- Check for condensate backup. Condensate backup can damage the refractory wall. If the wall falls against the rectifier probe, it may conduct the signal to ground, giving a false reading.
