Trane Heat Pump-Odd Sound when Shutting off

[Jeepster04]

Recently noticed an odd sound when this unit it shutting off. Its heating fine, no issues other than this sound when shutting off. It almost sounds like the reversing valve is reversing right as its shutting off. Removed the side panel and found a dead mouse, **** and pee everywhere, and the defrost board is coated in pee. Looks like the mouse chewed on it a bit too. Hate to just throw parts at it, but what are the chances something is wrong with the defrost board? It looks like another mouse might have exploded on the top capacitor.

 

[fitter30]

Mouse needs cpr and vacuum would help. Pull on all connections and push on terminals looking for loose or broken terminals. Video doesn't work.

 

[Jeepster04]

Should be able to see the video now.

Mouse didn't make it.

 

[karoc]

Guessing it’s your reversing valve or compressor. I don’t have to much heat pump experience, so my guess is just that.

 

[TRWham]

Should be able to see the video now.

Mouse didn't make it.

Check the voltage rating of your mouse. Apparently that one was insufficient.

When did you first hear this sound? Does it do the same thing in cooling mode?

 

[chinboys]

Don't know your location but it sounds normal with the compressor stopping and rattling due to heat call being met. And check the compressors vibration mounts too. And the thump could be the reversing valve going back to the default position. For heat pumps based in the south, the reversing valve defaults to the cooling position.
For your peace of mind, have a tech check the system out for current draw, super heat and sub cooling as well as for signs of a leak of refrigerant and compressor oil.

 

[bonneyman]

On the older scroll compressor equipped units they would make a noise like that immediately upon shutdown. It was the compressor going backwards for a few seconds as the pressure in the system equalized. The way the original scrolls were designed allowed them to do that so upon the next call for heat the comp wasn't fighting against high pressure while starting, as the previous pressure was released on shut-down. I think they put a one way only mechanism inside newer models so they could vent the pressure but not rattle backwards.
Don't know if your unit has a scroll but that's what it sounded like to me.

 

[justinjoyal]

Sounds like the compressor is going backwards at shutoff.

 

[Jeepster04]

Update, compressor self destructed. Unit was installed in 2006 and the compressor was replaced under warranty in 2011. R22 of course. I feel like it would've lasted longer if the unit didnt short cycle so much. Going to try to fix that.

Estimate is $14k for a new 5 ton 16 seer dual stage.