Heat pump Moose groan in defrost from scrolls

[gary_g]

I am used to the "swoosh" noise when the reversing valve actuates in the defrost cycle of a heat pump.

With my new Goodman heat pump, the scroll compressor makes a "Moose groan" for a few seconds, as well as the "swoosh", when going into/coming out of defrost.

What is the cause of this groan and why does it happen on scroll compressors only?

Other higher-end condensers have anti-Moose groan technology. What does it consist of?

I am thankful that there are no Mooses in Baltimore as the Goodman would have been mated by now.

Thanx from Bullwinkle, Jr.

[Swampfox]

Trane shuts the compressor off for 45 seconds going in and out of a defrost cycle, about all you can do to help with the noise you are hearing.

other than that, it is simply a noise issue, not damaging your compressor in any way

you should hear some of the first generation scrolls going into defrost :D

[woody19]

I have a 2 stage Bristol that does the same thing. Carrier engineering says it is caused by the reversing valve ( even with Quiet Shift) and they are working with the valve manuf. for some type of resolution. Apparently it has to do with the pressure of R410a and the orifice ports within the valve body. Not all will do it and it depends on what the pressures and amb temps are. I will be getting a test valve soon ( hopefully) to install and see what the results are.

[gary_g]

I have a 2 stage Bristol that does the same thing. Carrier engineering says it is caused by the reversing valve ( even with Quiet Shift) and they are working with the valve manuf. for some type of resolution. Apparently it has to do with the pressure of R410a and the orifice ports within the valve body. Not all will do it and it depends on what the pressures and amb temps are. I will be getting a test valve soon ( hopefully) to install and see what the results are.

Bullwinkle Jr has R22 refrigerant and a Copeland scroll.

[kuryakin]

If you had to hang around with a flying squirrel, making bad puns, you'd groan too!

Replaced a circa 1994 Bryant because the scroll compressor was SOOOOO damn noisy on startup and defrost. Once running, it was fine. The Lennox that replaced it made none of these funky noises, but then again, the compressor is in its own compartment and insulated.


I am used to the "swoosh" noise when the reversing valve actuates in the defrost cycle of a heat pump.

With my new Goodman heat pump, the scroll compressor makes a "Moose groan" for a few seconds, as well as the "swoosh", when going into/coming out of defrost.

What is the cause of this groan and why does it happen on scroll compressors only?

Other higher-end condensers have anti-Moose groan technology. What does it consist of?

I am thankful that there are no Mooses in Baltimore as the Goodman would have been mated by now.

Thanx from Bullwinkle, Jr.