Getting a 12 error code. The blower starts but no ignition. I checked the ignitor seems OK and the flame sensor I lightly sanded. Still same result. Any ideas?

Take the cover off the burner compartment of the furnace.

Observe the sequence of events that occurs at the furnace when you turn up the thermostat and post that sequence of events in order and in detail.

Most furnaces describe their diagnostic codes on a sticker on the furnace ---often inside the fan compartment door cover. What does it say for the diagnostic code you have?

The most likely cause of the problem is that the pressure switch isn't closing. You might want to use a multimeter to check that. One side of the pressure switch connection should be energized with 24 VAC whenever the inducer motor is operating. The other side should be energized with 24 VAC when the inducer motor comes up to speed. If only one side has the voltage, that would prevent the rest of the ignition sequence fro occurring.

The code shows 12 at first but after turning it off and resetting it reads 31. Pressure valve issue? Blower runs for bit then nothing the coil or wheel looking part turn for a bit then stopped. I checked the ignitor it has gone out before. I has scorched areas but I can't tell if its working or not. THe flame indicator I removed and replaced as well lightly sanded it looks OK. I live in MN rather not pay 200 to get tech here on Sunday centerpoint can't get here till Tuesday. Any suggestions? I noticed it went out last night been down for 10hrs now. Model 58DLA135-1-16 Carrier

As I supposed, the preswsure switch isn't closing.


Your last reply lacks the sequence of events and detail needed to be of help to you. Try again.

There's not much of sequence. The blower starts for about 2min. No ingition no attempt at ingnition the part w/ the wheel turns for a few seconds then stops. The error code flashes and that is all.

You have two "blowers." Which ones are turning on and for how long? You have to understand I can't read your mind. Think about what I need to know if I am going to be able to help YOU! You have to be detailed. You have to be specific. You have to relate what happens in sequence. Or you need to hire a repairman to do things for you.

You have a small motor that sets above the burners(inducer motor). It needs to start first to close the pressure switch. If its not starting that's the starting place for us to help you. I hope this info helps to get you started in the right direction for help.