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-   -   Trane furnace problem - can't figure out! (http://www.diychatroom.com/f17/trane-furnace-problem-cant-figure-out-120862/)

fedupfurnace 10-21-2011 08:15 PM

Trane furnace problem - can't figure out!
 
Let me start out by saying I am a complete novice and not mechanically inclined at all. I am writing here to get other opinions besides that of the HVAC company I'm using.

Here's what the furnace (Trane TUE080a936L0, XB80 model, nearly 10 years old) is doing:

1) The inducer motor starts, then nothing else happens. It then stops and restarts, then works properly.

or

2) The inducer motor starts, the ignitor glows, I hear a hiss of natural gas (and smell it), nothing else happens. It stops and restarts, then works properly.

or

1) then 2) above, then on the third try it works properly.

These problems are intermittent. The furnace can work for many cycles before malfunctioning.

The HVAC company has replaced the thermostat, the flame sensor, and finally the motherboard. These were all done in the last 3 days. A couple of years ago the ignitor was replaced.

I am at wits end. I don't want to replace the furnace if it could be something they're overlooking.

I would appreciate any input you can provide. Thanks in advance.

fedupfurnace 10-21-2011 09:19 PM

quick update: the furnace failed 3 times and locked out. the blinking led was 2 flashes...which just means that the furnace tried 3 times then failed. There's no indication of what might be the problem. All 3 tries, the system got to the point where gas is injected then it failed.

JJboy 10-21-2011 09:24 PM

I would check all the connectors, wires .... must have poor contact somewhere

Marty S. 10-21-2011 09:58 PM

Sure there's not a spider egg sack bouncing around in the orifice on that one burner that feeds the HSI? Remove the burner and unscrew the brass orifice to check.

hvactech126 10-21-2011 10:03 PM

clean your burners and crossovers.

biggles 10-22-2011 07:00 AM

that ID cycling on a heating call makes me think the stat might be causing the starting problems....did you try jumping R to W right down at the furnace to see if you get a solid start from repowering the 115V safety switch on the furnace....just a thought:whistling2:

fedupfurnace 10-22-2011 10:38 AM

Quote:

Originally Posted by biggles (Post 753985)
that ID cycling on a heating call makes me think the stat might be causing the starting problems....did you try jumping R to W right down at the furnace to see if you get a solid start from repowering the 115V safety switch on the furnace....just a thought:whistling2:


Thanks for your advice, however, I don't know anything about this terminology. What doews jumping R to W mean?

Also, here's some further information in case it helps. When the new thermostat was installed, the furnace now comes on many more times than it used to. (Remember the problem was there even with the old thermostat). With the old thermo, it would turn the furnace on when the temperature was 1 degree below setting, then shut off at 1 degree above setting. It now comes on and turns off within tenths of a degree change because the thermostat temperature never changes while it's running.

Since the thermostat was changed and we still have the problem, is it feasible that there could be a wiring issue between the stat and the furnace?

Since we got up this morning, the furnace has run around 10 times with no issues (last 2 hours or so).

biggles 10-22-2011 03:21 PM

remove the stat from the subbase,.....now go down on the furnace and JUMP with a thin stat wire R to W your simulating the stat with no control on temp as long as the jump it there...remove it and the furnace shuts off....that not reading a temp when the heat is running might be something check the configuations on the stat something is doing it do you have setback settings on the new stat as in wake/leave/return/sleep with options for time/temp adjustments for the house and the daily routine?when that inducer motor runs thats the stat calling it in everything else is connected to the air into the burner chamber...pressure switch closes indicating air induced spark and proof of flame and the main gas.....:huh: try that straight out jump on R to W either at the stat subbase(in fact do it there to proff out the wires for het down to the boiler) or down at the furnace both should be the same run reaction....might need a rabi or priest in next....:wink:


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