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Bart Jay
Bart Jay, HVAC Technician
Category: HVAC
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Experience:  35 years in HVAC. NATE Certified EPA certified
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I have a bryant +90 furnace model 398AAW036080D. When it calls

Resolved Question:

I have a bryant +90 furnace model 398AAW036080D. When it calls for heat the inducer motor runs but the ignitor does not fire the inducer continues to run
Submitted: 6 years ago.
Category: HVAC
Expert:  Bart Jay replied 6 years ago.

If you are watching it happen to you hear a click, like the gas valve opening?

 

Is there a small window in the blower door that if you look in see a LED blinking? Count the blinks

Customer: replied 6 years ago.

The only click I hear is the relay for the blower and the differential switch. I wasn't able to locate any LEDs.

Expert:  Bart Jay replied 6 years ago.
Does the indoor blower come on? Do you have a voltmeter?
Customer: replied 6 years ago.
No the indoor blower does not come on. Normally the burners turn on first but they are not.
Expert:  Bart Jay replied 6 years ago.

There is a draft proving switch. It is a round silver control with two wire go to it.Turn to switch off. If you remove one wire and turn the furnace on after the draft motor come up to speed touch the two wire together.. If the ingnitor comes on the problem is in the draft proving circuit. If not I would bet the ingnitor is bad...

 

Oh where to you live. Is the flue piping buried under snow form the storm in the northeast today???

Customer: replied 6 years ago.

The only Round silver control I can see is what I called the differntial switch. It has 3 wires N.O. and N.C. contacts. i Jumpered the N.C. contact so the inducer blower would start and then moved the jumper to the N.O. contact and still nothing happened.

 

Expert:  Bart Jay replied 6 years ago.

I am sorry i just looked and it seems you furnace has a spark ignition system not hot surface. . Can you see the pilot burner? Just kicks tap it with a screwdriver handle. If nothing carefully remove the orange spark wire. While it is running hold the tip close to something metal on the furnace. Does it spark?

Customer: replied 6 years ago.
No spark. I jumpered the input for the igniter and can hear it click but saw no spark.
Expert:  Bart Jay replied 6 years ago.

It is a small back or gray box with the orange wire coming from the center, Correct?

 

What did you jump on that box? It should be two 24 volt wires and the spark wire

Customer: replied 6 years ago.
Correct. There was a yellow and brown wire on one of the gas valve terminals that had 24V i jumpered that to the green wire.
Expert:  Bart Jay replied 6 years ago.

If you have no spark the ingnitor is bad. If you have 24 to it and no spark that is it. you can try to light it with a long match or one of the new long lighter. Start the furnace and try lighting it. Gas should be following from the pilot. You will only get one cycle but better then nothing

 

The part number of the ingnitor box is LH33WZ510.

 

Hope this helped and good luck. Please accept and positive feedback is appreciated

Customer: replied 6 years ago.
It was the switch that senses the pilot. The NC contact was open.
Expert:  Bart Jay replied 6 years ago.
Ok good but you said you remove a wire do the fan would start. That would have done the same thing. Did you have a tech fix it or DIY
Customer: replied 6 years ago.
Had to call a tech, I needed heat and that was the only way to get it fixed last night. Thanks for the help.
Expert:  Bart Jay replied 6 years ago.
Ok good Luck
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