I have a Trane XL14C dual fuel unit that was installed about 3 years ago. Every since the install, the gas pack has not worked correctly. It hasnt been super important, as the temp rarely gets low enough to trigger the gas pack, but wouldnt you know it, the compressor died over the holiday week, and I was stuck with the gas pack that didnt work.

I have had 2 different service companies and the installer look at the issue. They replaced the computer unit, another tech cleaned the sensor, and another tech wanted to replace the computer again (I declined).

I have been forced to troubleshoot it now, and I think I have enough information that gives me a clue of where I should point the next service technician that is coming out to replace a broken compressor on Thursday. There is no committment to them, so if someone on here is qualified to replace the compressor (parts under warranty) and can fix this, I'll be happy to cancel the call.

For testing the burner...
When I open the inspection panel and start the unit, without failure, the left burner (there are two burners) will light. Soon after it lights, it shuts off. A few seconds later, it lights again. It tries this three times total and then gives up. This is the first indication that the unit does not think the burner is lighting, and makes the flame sensor suspect. With this particular unit, I don’t know if both burners are supposed to light in stage one (low). What I have noticed is that the right burner is never initially lit. Just the left. To troubleshoot more, and possibly blow my house up, I bent the right flame sensor so that it would be in contact with the left burner. When I tried turning on the unit this time, it lit and stayed on. I watched the burner for a few minutes, and after a few minutes, the flame on the right burner was ignited. I assume it was ignited when the unit switched to Stage 2 (High) and enough gas flowed past the first burner to the second burner, enough to light it.

What does this suggest is the likely problem? Does the low side adjustment screw need to allow more gas into the feed? I don’t think this has anything to do with the computer since I essentially hot-wired the flame sensors to both show hot on the same burner. This also rules out the sensors being faulty or dirty. IF both burners are NOT supposed to be lit on startup (only the left on stage 1 and both on stage 2- I don’t think this is the case), then it is possible that the sensors were crosswired to the computer (the left sensor is plugged into the computer detecting the right side and vice versa).

Help/Advice would be appreciated.

12/27/2011 2:02:03 PM

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12/27/2011 2:33:28 PM

try this thread message_topic.aspx?topic=535582 and ask CalledToArms

12/27/2011 2:35:04 PM