Heat pump flickering/rattling sound

[pelikan61]

Hello everyone, I'm plugged in to shore power at home to 50 amp with a 30 amp dog bone to a 2021 Isata 3. Heat pump ON set at 70 degrees with the outside temperature 41 degrees. Everything seems to be working fine, and maintaining a constant 69-71 degrees inside. Except when it is running, it makes an obvious flickering sound outside on the roof. You can't hear it inside. Is that normal? Does it have anything to do with what I've read about heat pumps not being the most efficient around 40 degrees or below? I did run it a couple of days ago but did not hear the sound. Although, I can't remember what the temperature was then. Thanks again

[vlamgat]

You don't say what model of A/C is installed but my guess is that its the same Airxcel as installed in the Isata 5. In which case you are probably hearing the the chattering relay on the transformer of the control PCB. Several of us have experienced this and it comes from a defective component.

The procedure to address it is to download the AC performance validation sheet from the Airxcel web site and get an Airxcel distributor to complete and sign the document. They should then document the noise issue and submit a request to Airxcel for a replacement PCB. These are in short supply and you may have to wait weeks for the replacement to be sent so that it can be installed by the dealer. You cannot install it yourself without losing the warranty.

[pelikan61]

Thank you so much, what I have is a Airexcel 45000 series. I believe model number 45054-6792. So for now the noise has stopped.
However, I plan on going with your suggestion of AC performance validation.
Also, would there be additional damage with continued use assuming I'm out camping and the chatter starts again?

[bclemens]

Originally Posted by pelikan61

Thank you so much, what I have is a Airexcel 45000 series. I believe model number 45054-6792. So for now the noise has stopped.
However, I plan on going with your suggestion of AC performance validation.
Also, would there be additional damage with continued use assuming I'm out camping and the chatter starts again?

It would be helpful to shoot a video of the chatter so we can hear it. All of the people that have the board/humming issue have been able to hear it inside. So I would not automatically assume you have this. I also think it is heard when the A/C is NOT running...but not 100% sure of that one.

[pelikan61]

Roger that, unfortunately it has stopped for now. but I will certainly do that next time it does.

[vlamgat]

It was definitely inaudible when running and audible everywhere in the kitchen area. When I had the problem validated, I went up onto the roof with the tech to see for myself and it was much louder up there than in the coach.

So Brian is probably correct that you seem to have another problem. That it's disappeared and is only heard while running, seems more ominous but unless you can get it documented by a dealer, I would postpone getting the form completed.

[pelikan61]

Makes sense, thank you.