[Berty29]

Good morning,
I have a 80 plus day and night furnace.
It was working fine but when I came back from my month long trip. It wouldn't start, I went downstairs and turn the switch off and on and the engine started but there was no glowing on the ignitor and after a couple of minutes it the engine turned off again.
I did turn the switch off and on again and the same process repeated itself without any different result.

Is it the ignitor the problem?
Should I use sandpaper on it to see if the build up carbon is the reason that it doesn't start?

Thank you for your help,
Bert

[Grady White]

You need to measure the voltage to the ignitor with a voltmeter. During the ignition process you should get 120 volts ac to the ignitor. If you do & the ignitor doesn't glow, the ignitor needs to be replaced.