Problem with a TRANE xl 90

[elwayo7]

I am currently a second year student at Ivy Tech college going for HVAC. So I'm still new and eager to learn. But the vent motor runs continous with no heat. I checked the condesate drain and found no blockage. Also it will try and ignite the burners but gets nothing then a red blinking light on the circuit board? would appreciate any advice! ( It's my moms furnace.

[htg guy]

How many times does the red light flash? Does the ignitor glow red or not at all?

Possibly an ignitor failure, but beyond that you need to call for reinforcements.

[BaldLoonie]

Complete model #? The XL90 could be a couple totally different furnaces. The old XL90 used an inducer relay which could stick on. The newer furnace has an integrated board with diagnosing light.

[elwayo7]

It is has the integrated board. I have heard that some of the Tranes have burner problems could this be a possibility. The light blinks continously after trying to ignite.

[BaldLoonie]

If it is the Intell-ignition board, good luck. That thing is so full of bugs, you'd think it was a Windows product :D

See what the flashing LED is telling you. That's the first step. If it reports open limit, confirm that they are really open. That's one bug we frequently find. It blinks 4 times yet we prove the limit circuit is fine and have to replace the board.

[BaldLoonie]

Last night, our on-call tech called me. Had a single stage furnace doing the same thing. No call for heat, inducer sat there and ran, LED was normal. Another Intell-ignition board bites the dust. Luckily our supplier covers them all in warranty regardless of age.

[airconman]

the tuy furnace had a problem in I believe august but most should have been field fixed by now..... they set a code 3 or 6 for no reason... Trane dealers should have got the bulletin to fix them though.