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Yes, that is what seems to be happening.
I have a followup, the board was replaced yesterday afternoon. When testing the new board it has the exact same symptom of the old one.
I did a little testing myself and after the unit had shut off I still heard a buzzing, I pulled the reversing valve lead off the defrost board and sure enough the buzzing stopped.
I reconnected it, went inside and kicked on another heat cycle, the unit did a proper defrost, fan didnt start, compressor ran, about 45 seconds later the fan kicked, a blast of warm air (from the coils) then i heard the reversing valve go back to heat mode.
I shorted the test pins after 5-10 minutes and the unit went into defrost, the reversing valve hit, and the unit got really loud, the fan still running.
Is it possible that my unit isnt supposed to kick off the fan if it goes into defrost mid cycle?
The Model is: NHP036AKC2
As I sit here typing this I heard the unit get quiet again, probably went out of defrost.
Its wired correctly best I can tell.
The reverse valve was only energized when the board was calling for defrost or in cooling mode, in cooling mode the valve stays energized the entire time.
At least thats what the Electrician who came out said (for background he is the one who installed it 8 years ago)
I called him again this morning, he thinks we may have gotten a bad board and/or the sensor is bad. I suspect something more.
Regardless if the thermostat initiates a cooling cycle then O is energized (I think) and the defrost board reverses the valve and keeps that energized regardless of whether the thermostat is calling for cooling or not.
When the board is in defrost mode it was energized as well, to me it seemed like this morning it started a defrost cycle just as the thermostat was satisfied, so when i realized the RV was energized I went inside and forced the thermostat to kick another heating cycle, which made it run what seemed like a normal defrost.
So it seems like the reversing valve is good (when he was out yesterday he manually reversed it mid cycle, by energizing the orange wire to the board) The sensor seems good by the fact that when it defrosted normally as soon as it hit the temp it un-reversed and the fan kicked on, The contactor seems normal since things are turning on and off (I dont know much about this)
So could I have just gotten a bad board with the exact same symptoms as the first one?
My system does not have pressure switches, and as such has a jumper wire between the pins.
I cant think of any more detail to give, it befuddles me that it could be that the replacement board was bad, but it has the exact same symptoms...
What else could fail that would cause everything to operate normally except the defrost cycle when the unit is mid cycle?