Furnace sparks but never lights
2019 travel trailer, ducted furnace. 30A shore
Customer says: The furnace fan comes on and I hear clicking, but no flame. After three tries it shuts down.
Battery is good.
Tests you can run
- 12V at the furnace while it runs
- Light a stove burner
- Watch and listen for the igniter
- Sail switch with the blower running
- Voltage at the gas valve during the ignition try
- Gas pressure at the valve inlet during the try
- Gas pressure at the valve outlet during the try
- Swap in a known good control board
- Jumper the sail switch to see if it lights
Repair options
Keep going on furnaces
Learn it
Prove it
- Furnace blows cold
- Furnace keeps shutting off, fan keeps blowing
- Thermostat clicks, furnace does nothing
- Comeback: furnace quits again