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Boise_Chief
01-02-2011, 06:11 PM
I have a Trane furnace that just won't keep running. If you know anything about furnaces let this distract you for a few and help me figure this out.

It keeps going into lockout.
Burner runs for 1 min 30 secs off for 20 secs back on for 130 rinse and repeat 6 times and then goes into lockout. I can't figure out if this is the limit or the flame sensor, any hvac guys on tonight>>

Bwana
01-02-2011, 06:16 PM
Is your flame sensor dirty? Any carbon build up? It does sound more like a relay, or switch, but it wouldn't hurt to check.

Bugeater
01-02-2011, 06:17 PM
I should be able to answer this question in May.

OldTownChief
01-02-2011, 06:18 PM
Probably your pressure switch or the inducer motor. What is the error msg?

LaChapelle
01-02-2011, 06:18 PM
Sounds like a classic themo coupling failure

Boise_Chief
01-02-2011, 06:22 PM
Older trane so there is no light codes. I think the number of restarts before lock out can tell weather it is limit pressure or flame sensor but can't find anything on the net. It is driving me nuts and it is cold outside....

OldTownChief
01-02-2011, 06:22 PM
If the board doesn't see that the inducer motor activates the pressure switch you will get the result you are getting but you should have a flashing light on the board that will give you an error code for the failure.

Bwana
01-02-2011, 06:23 PM
If the board doesn't see that the inducer motor activates the pressure switch you will get the result you are getting but you should have a flashing light on the board that will give you an error code for the failure.

Exactly, there should be a code.

OldTownChief
01-02-2011, 06:25 PM
If it's old enough you should be able to bypass the pressure switch but don't leave it that way. Does the inducer motor start up?

Boise_Chief
01-02-2011, 06:29 PM
Yeas the induction motor is starting and running at a good speed. I'll try to bypass the pressure switch and let it run a couple of cycles. There isn't a led on the board on this particular model.

OldTownChief
01-02-2011, 06:31 PM
Yeas the induction motor is starting and running at a good speed. I'll try to bypass the pressure switch and let it run a couple of cycles. There isn't a led on the board on this particular model.

Depending on the year, bypassing the switch will also cause a failure but it will be a different sequence.

EDIT: You are correct, it is an induction motor (not inducer) lol I'm a refrigeration guy.

plbrdude
01-02-2011, 06:31 PM
flame senseors are usually somewhat easy to get out. shut it off and pull it out and clean it w/some sand paper or even scrape it w/a paring knife. put it back in and fire it up and see what happens. if it keeps going out you need to dig deeper. + bypassing the pressure switch prolly won't work. even the older boards are geared to not start the furnace if it reads that the circuit is closed on the call for heat.

Extra Point
01-02-2011, 06:33 PM
Check and see if your igniter is working-- glow or spark type.

morphius
01-02-2011, 06:36 PM
I have a Trane and it started acting funny last week. It would light, but kill it off 5 seconds later, and then repeat a bunch of times. I cleaned off the flame sensor just a little bit and it has run fine since.

Bwana
01-02-2011, 06:37 PM
[quote=plbrdude;7315912]flame senseors are usually somewhat easy to get out. quote]

Heh, that was my theory last year. It went something like this:

Grab, pull, *SNAP*......SON OF A BITCH!!:cuss: Hey, at least the install of the new one was gravy. :doh!:

Boise_Chief
01-02-2011, 06:41 PM
Hmm lost a reply there..
I ran a multi meter on it and the voltage spiked before the flame shut off. this is at the press switch.

Boise_Chief
01-02-2011, 06:44 PM
Ill be gone for a bit brb

Boise_Chief
01-03-2011, 08:10 PM
So I have finally figured it out, on this particular Trane it uses a different kind of flame sensor. It isn't a normal thermocouple type rod, it has a window in the top and i'm still not sure how it senses but it was bad. It would not quite open the circuit and would fluxuate the voltage to the gas valve. Anyway i repositioned it closer to the flame and It worked better. $15 dollar part and it is going now.

Thanks to all who helped or were just smart asses..

Extra Point
01-03-2011, 08:21 PM
Well, I was a dumbass for not reading your description entirely. Glad you got it up and running. For the 11 years we've lived in this house, we've spent money on two igniters and two blower motors. I guess that's not bad, but the efficiency in our Goodman isn't all that woopie, for being 17 years old.

Phobia
01-03-2011, 08:26 PM
Some of the tranes have differing types of flame sensors. Make sure yours is the thermocouple valve. If it's not, I'll bet you have to replace it. It's only about $15 and you should be fine.

Bugeater
01-03-2011, 09:02 PM
So I have finally figured it out, on this particular Trane it uses a different kind of flame sensor. It isn't a normal thermocouple type rod, it has a window in the top and i'm still not sure how it senses but it was bad. It would not quite open the circuit and would fluxuate the voltage to the gas valve. Anyway i repositioned it closer to the flame and It worked better. $15 dollar part and it is going now.

Thanks to all who helped or were just smart asses..
Just FTR, I wasn't being a smartass, I'm going to school for this stuff and my gas heat course is next quarter.