Heat Pumps and Electric Heating - Solution to Heat Pump defrost cycle noise for Carrier and Bryant

I purchased a Bryant Heat Pump in July of 2003. That fall I noticed a loud wooshing/moaning sound whenever the unit went in/out of defrost cycle. I contacted my dealer and worked with Carrier tech support for over a year on this. They even gave me a new unit which made the exact same noise. Finally they told me they would take my old unit and run it in a tesing facility to isolate what was making this noise. They called it the "moose call". They determined it was the reversing valve and would replace mine as soon as they found a replacement that worked. The new valve was installed on 11/26/2004 and it seems to be fixed. My dealer ran the unit through multiple defrost cycles and it sounds completely different. The woosh is much quieter and the "moose call" is gone. So far so good. Hopefully it lasts. I give credit to the persistance of my dealer and Carriers tech support person, Kurt Peterson. He works for Carrier Northeast at 860-635-6500 ext 5.

All heatpumps will make some noise from the 4 way valve
in the outdoor unit. When it goes to defrost the valve works cause the unit is going into the AC set up. Some old units the valve would work when you went to heat. but they found out if the valve stoped then you didnt have any heat just AC. So now when the unit is off the heatpump is set for heat anytime . This way should the valve go out on you in winter you will still have heat but no AC or defrost.


ED ;)

Our newly installed Carrier Infinity heat pump makes a loud snorting noise, like an elephant call, or a tool box scraping on a cement floor. This noise lasts a second or two and only occurs in cooler weather near and below the freezing mark. Otherwise, it works fine. For the entire winter season on the coast, whenever the temperatures dips to freezing or below, we have been wakened during the night by this loud trumpet burst noise just prior to the unit going into its defrosting cycle. The unit goes into auxiliary heat to help defrost the outside coils outside and we see the steam rising.

Several visits by the installer and several calls to Carrier have been made but despite adjustments to dip switches and whatever else (no new parts) the noise persists.

It appears from the previous post that this noise problem has been around at least since 2004 and the fix required replacing the reversing valve which Carrier appears reluctant to do without putting the consumer to a lot of trouble.

Has anyone else experienced this problem?

My Carrier Heat pump is just one month old. It has started to get very cold - freezing temps and my heat pump also makes that loud Moose Call sound every once in a while. . . NOt impressed. It was supposed to be a quiet unit. I will call the installer and see if the noise can be repaired.

Alot of units come from the factory with the default settings on the defrost circuit board. These circuit boards are not set for use with newer scroll compressors by default. There should be a jumper on the board to set a delay of about 30 seconds before going into defrost so that the pressure can rebalance. With the delay set the unit will run quieter.

Has anyone come up with a solution for the defrost noise that happens with the Bryant Heat Pump? We've had the installer come out twice to make the adjustments, and the noise still wakes us up in the middle of the night, as well as as drowning out our television when we are awake. Any help would be greatly appreciated!

Thank you.

Alot of units come from the factory with the default settings on the defrost circuit board. These circuit boards are not set for use with newer scroll compressors by default. There should be a jumper on the board to set a delay of about 30 seconds before going into defrost so that the pressure can rebalance. With the delay set the unit will run quieter.

Is this for Carrier units? I have called the installer and he says the noise is 'normal'. grrrrr :madhell:

Has anyone come up with a solution for the defrost noise that happens with the Bryant Heat Pump? We've had the installer come out twice to make the adjustments, and the noise still wakes us up in the middle of the night, as well as as drowning out our television when we are awake. Any help would be greatly appreciated!

Thank you.

Anyone? My Bryant heat pump is doing the same thing, and with the darn thing right outside the master bedroom wall, it's ridiculous! What's the fix!?!? :wall:

In 2007 I bought a 5 ton Carrier Infinity. - the biggest and best that Carrier had then. I'm on acreage and I wanted the compressor put away from the house, but the coy gave me literature from Carrier saying it made the noise of a "household refrigerator" and said it should be put alongside the house and I'd never hear it.

What a load of collywobbles!

People talk about a loud whoosing noise - that's nothing - mine goes off like a truck's airbrakes - every 20 minutes in the cold season!!

And then there is the loud noise when the motor starts up after the defrost cycle.

And as for the household refrigerator noise - that is just a bald faced lie. In normal running during summer it is quiet, but in winter it drops into its second stage and is definitely noisy.

I wish I had stuck to my guns and got a geothermal unit - I have the space. Problem was the air source are so easy for the contractor to install - and when I bought mine it was the middle of the building boom and the contractors were picking and choosing their work - that the contractors here could not be bothered with the time to install a ground source.

My dealer is coming by today with a Carrier rep to repair the moose call noise. It is the reverse valve that Carrier admits it is/was having problems with.

Btw, when I first told my dealer of the noise he said it was normal but I was kindly insistant that it wasn't . . . so, it's now getting handled! Call your dealers be persistant. Loud defrosting noises is NOT normal.

June/08, installed a Infinity Series Carrier HP w/natural gas Hybrid 3 Ton unit. I have been living with this "Moose Call" noise since cold weather. Have had Carrier Rep here as well as the installer. We tried various things and did select the quiet shift but did not help. No solution yet found, so I was glad to read that my suspicions are confirmed that it is the reversing valve. I selected this unit because we live in close proximity to other homes and because of it's advertised "Quiet Operation" (like a refridgerator, ya right).