My furnace is a Carrier 58GS075. It seems to cycle correctly:
- Igniter sparks and ignites*
- 20-30 second pause.
- Main burners are opened and ignite.
- 30-60 seconds and blower turns on.
- Remains on until heat is satisfied.
- Main burners shutoff.
- Blower turns off 45 seconds later.
However, during the whole process (steps 1-5) the igniter is rapidly sparking, but the flame is already established after 1-2 sparks.
I bought a whole new igniter off eBay a few months ago to try to fix this issue, however it is still occurring.
I also bought a whole new circuit board about 2 months ago for a different issue. The igniter issue persisted between circuit boards.
I would imagine the cycle would be irregular if the furnace did not think the igniter was lit? (shutting down main burners, etc) But it cycles correctly so maybe it is something else?