control boards

[t-dog]

I have a question on trane control boards but could pertain to any board. I have had 3 or 4 calls with intermiten problems. the dia. lite flashes 4 on trane that is an open high limit. When i check limit it is fine. Is it normal for these board to give false readings. Change board?

[bryancorfu]

I would check everything before condeming an ifc. check your temp rise,gas pressure. cycle furnace and see whats hapening. When in doubt jump it out. Be patient and use your head.

[fixer]

I have had to change 3 boards and Trane furnaces this heating season due to false readings saying open high limit switch.
It was the board on all 3 counts.

[hvac wiz 79]

not familiar with tranes controllers on resi equip but do they store error conditions ? maybe last error is one being indicated or is unit locked out on that code while u check it to be fine. also a high or unstable ohm reading across the limit may cause voltage drop enough for board to think switch is open. other than that if ur not familiar with this stuff call a pro

[BaldLoonie]

One of the many bugs of the Intell-ignition board. If you find that error code but your meter disagrees, dispose of board. Look for the latest version, CNT3798 for single stage. Supposedly more reliable.

[hvac wiz 79]

wow thats weird about those boards . now i have changed my fair share of boards (dif brands) but seldom find "alot" of defective boards in a calender year. Do these issues with trane boards happen during warranty period ?

[t-dog]

wow thats weird about those boards . now i have changed my fair share of boards (dif brands) but seldom find "alot" of defective boards in a calender year. Do these issues with trane boards happen during warranty period ?



Yes wiz 33 i have changed several that were still in warranty.

[BaldLoonie]

One of our poor customers is on her 4th Intell board. We had the tech rep from the supply house check out the job to be sure nothing we did 6 years ago is causing all these failures. Not only did they cover the 6 year old board but gave us labor money to change it out so we could satisfy the customer. Above & beyond but yes, that board was a lemon and hopefully by now fixed.

[kpsheets0580]

I bet I have replaced at least two boards every week this winter. Always the same problem. Light flashes four times with all limits closed. Check the back of the board and you will usually see a brown spot on it towards the bottom. We have seen this on both the silicone nitrate and silicone carbide boards. Seems to mostly effect downflow models. Possibly caused by excessive heat build up since the board is not in the airstream like they are on upflows.