We have a carrier 40QNB024 High Wall Fan Coil Unit, that has decided to not tell the outside unit to come on.
The manual states that there is diagnostic LED codes to help you to troubleshoot, but the system doesn't think there is an error.
- reset the unit completely (remote too)
- Bypassed the drain pump to ensure it wasnt a pump failure
- put new batteries into the remote..
the outside just doesn't get the signal when its operating in normal mode.
If i throw it to 'test' then it cools down fast, but if I set it to its normal day to day, it could work for a couple hours, then stop working (and again, no LED's blinking to signal an error). After going over it, my carrier dealer has determined that he thinks its the controller board ( 42KNAB850LF or 42KNAB5850LF). But Carrier (Canada) doesn't have the board, and carrier US says they aren't running production until Mid October.. and maybe 4 weeks after that they would have special order stock to send me one.
So.. I'm looking for someone that either may have one, or if anyone has any other thoughts. we're scratching our heads over it.