www.hvactechgroup.com - forums

My furnace board is clicking OFF and right back ON, sometimes does it a few times. Flame stays ON, I believe the relay that clicks off is for the large blower fan.

What could be causing the relay to be shutting down the fan, and then turning it right back on?

I know if the flame goes out it could be one of many sensors (temp sensors, or the exhaust fan pressure switch), but I didn't know there was anything in there that would shut down the main large blower fan?

Could the relay just be bad/weak from being old? Like it happens on cars sometimes when a relay is old and contacts inside are dirty/burned?

Anyones input is much appreciated
Thanks everyone for reading

Doesn't sound like a flame related issue. Could be the relay itself, burnt up contacts, or something on the board that is faulty letting the relay go on/off. I would double check all connections, and if that does nothing and you don't throw any fault codes, it may be time for a new board.