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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Our trane xl90 has the vent motor running but the blower is

Customer Question

Customer: My name is***** trane xl90 has the vent motor running but the blower is not kicking in. There is a steady flashing red light on the diagnostic. I changed out the igniter, which is what the problem usually is, but it still will not ignite.
JA: Thanks. Can you give me any more details about your issue?
Customer: The vent motor is running, but the furnace will not ignite the burner. The red light is flashing steady on the diagnostic.
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Submitted: 1 year ago.
Category: HVAC
Expert:  Scott replied 1 year ago.


This is Scott at any time is the light flashing a code indicated by a pause in the flashing and at anytime does the new ignitor glow.

Customer: replied 1 year ago.
I have not noticed a pause. The flashing is steady, fairly fast and begins after the furnace has tried to kick in 2 or 3 times. No activity on the igniter, which usually starts on that cycle.
Expert:  Scott replied 1 year ago.

Well at least we know by the fast steady flash that the thermostat is sending a signal to the unit, also you say the inducer/draft motor is running correct?

Customer: replied 1 year ago.
the draft motor is running. I am wondering if the igniter that I installed may have been a defective one. We have had an extra on hand for a while. It looked ok; the element was clean with no breaks, but the ceramic looked like it had been used before.
Expert:  Scott replied 1 year ago.

It appears that the pressure switch is not pulling in and continuing with the cycle of the furnace, do you have a multi-meter at your disposal Phil?, if not you can turn the power off to the furnace and back on again to recycle it ad whil it is running tap the pressure switch. also you should make sure the exhaust and inake pipes are clear.

Expert:  Scott replied 1 year ago.

If you have a multimeter you can do an ohm check on the igniter to test its integrity.

Customer: replied 1 year ago.
OK Scott, I will do that. I have a multimeter. I am at work now, so will do that later this afternoon. Thanks!
Expert:  Scott replied 1 year ago.

If the igniter is indeed bad that is in there after the draft motor starts you will here the gas valve click 17-40 seconds after the motor starts. you can also test for voltage at the recepticale for the ignitor. Great Phil just repond later and let me know how it turns out for you.

Customer: replied 1 year ago.
Will do Scott. Thanks for your help!