Furnace

Apr 19, 2015 4 Replies

I have a ~ 12 year old Carrier gas furnace. Most recently (at least at the end of the heating) it has failed. It will begin to start, then ~40 seconds later shut down. It does not appear that there is ever any combustion.



Maybe 5 years ago, while I was on a trip, a similar situation occured. Then my wife made a service call, where the repair guy replaced the Ignitor.



Is there a way I can Now verify that the ignitor (~$22 part) has again failed?



Might there be other likely causes, to our Failure to Start situation?


Dave,

Quite a few YouTube videos show how to do this.

Dave M.

Cut-off power to the unit...turn it on and watch thru the sight glass to se e the ignitor. It will take awhile to cycle...the fan will run and then sto p, then it will cycle. If you see the ignitor work then check the drain as it may be clogged. There are also flashing codes for diagnostic on the main board.

Typically there are some flashing LEDs on the control board to give you code for what the problem is. I take it that it does not light at all? Besides ignitor it could be no gas, bad gas valve. They also have some checks for proper pressure in the venting system, not sure if that test has to pass before it will fire, but probably does, so it could be blocked vent, bad inducer blower...

Hi, No error code?(blinking LED on the control board). If you want to check HSI(hot surface ignitor) unplug it and measure it with multimeter. HSI is known to burn out, when and if you replace it, don't leave your finger oil on the heating element ie. don't touch it with bare hand. When HSI comes on in the ignition sequence it turns red hot bright, it is easy to see through cover panel grills or little round clear window. I always keep spare HSI near the furnace(A carrier)

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