This is an odd one... Trane system. - http://www.hvacmechanic.com/ Forums
Original message
| csmpez
 |  "This is an odd one... Trane system."
, posted Fri 15 Aug 01:37  
I have a Trane XR90 gas heating and air conditioning system for my first floor. The programmable T-Stat is set to go from 79 to 86 at 10pm. When it was 10pm the T-Stat did its thing and switched to 86 degrees following its programmed schedule. However, I could still hear the air handler running down in the basement and there was air still coming out of the vents. I got up and checked the T-Stat and it was 79 degrees in the room and the T-Stat was set at 86 degrees for its 10pm program, on COOL w/fan set to AUTO. I went downstairs in the basement and could hear the furnance exhaust. I went to the breaker box and shut the power off for the gas furnance, which shut off the air handler/furnance. I turned the power back on and the gas furance came back on again. I went upstairs and pulled the T-Stat from the wall wondering it was the T-stat... gas furnance still continued to run. I went outside to see if the a/c unit was running... NOPE. Went back downstairs and pulled the panel to the air handler while it was running disconnected the green wire thinking it could be a fan relay issue, no affect... disconnected the yellow wire... furnance stopped. Reconnected the yellow wire, furnance still stayed off with the little red led light blinking (seems to blink all the time). Went back upstairs, reconnected the digital T-Stat, turned the temp down to 75 degrees to see if the system would come on w/out the furnance. A/C came on w/out furnance running, so I clicked on the schedule button on the T-Stat to set the temp to 86 degrees and the a/c subsequently clicked of off... furnance stayed off.
Can anyone here explain why on earth did the furnance come on while the a/c was running and then wouldn't shut off? Also, the air coming out of the vents wasn't warm, so I doubt the gas burner came on. I'm just trying to understand what happened as this just didn't make any sense. Thanks.
Scott
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Replies:
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| envirosystemtec
| "Re(1):This is an odd one... Trane system." , posted Sat 16 Aug 11:45
go though the low voltage wiring check for shorts what kind of stat do you have ?may your control board is going bad
tim
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| | csmpez
| "Re(2):This is an odd one... Trane system." , posted Sun 17 Aug 03:48:
The T-Stat is a Honeywell 8000 series (8321). I looked over the wiring in the AH and everything looked pretty good. I did fix some wiring outside in the A/C unit several months back that was damaged by a bird who made a nest inside where the wiring is located.
[this message was edited by csmpez on Sun 17 Aug 03:51] |
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