humming sounds from heat pump


Old 03-05-07, 08:21 PM
Thread Starter
Join Date: Mar 2007
Posts: 2
Received 0 Votes on 0 Posts
humming sounds from heat pump

Our Lennox heat pump compressor went bad. The unit is about 6 yrs. old. It was stalling out, and when service came it just seized up. They did diagnostics and could not find anything else wrong with the system. We asked a lot of questions about other possible problems and they mentioned a valve which couldnít be checked until the new compressor installed. Other than that, all other parts that could have caused it are being replaced anyway. They said they have had this happen with the compressor just going bad. The compressor had to be replaced and also the capacitator and some other parts. After the install, that valve and everything else was checked and ok.

We are new to heat pumps and wanted to mention, before the compressor was replaced and even now afterwards, when the heat pump would start, it would hum as usual but sometimes the hum would get louder, not ear piercing, just louder, then it would go back itís normal hum. Today it hummed normally, then got a bit louder for a few seconds, then normal, then louder for a few, then normal again. Or it may hum a bit louder for a few quick seconds right before it shuts off. Sometimes it just keeps a constant normal hum. I called and was told this was normal, that heat pumps make all sorts of noises, especially in winter, or they said it could be in defrost cycle, also normal. But I thought defrost cycle made a swooshing sound, not a louder hum. I also checked with neighbor and he said his does the same thing. When it does this, the heat is working fine. Just want to make sure this is normal.
Sponsored Links
Old 03-06-07, 12:33 PM
Join Date: Oct 2005
Posts: 149
Received 0 Votes on 0 Posts
I also have a lennox heat pump and the humming noise you are hearing is probably the unit in deferost. You will hear a "swishing" sound when its switching from defrost back to the normal heat cycle, but while it is defrosting you will hear a humming noise since only the compressor is operating on the outside unit during defrost. Also, if my unit has frosted up a bit it may sound a little louder since its working harder, but as soon as the defrost cycle clears it up it quiets down. I am not a tech by any means but thats possibly what you are hearing. I will say if you hear the humming noise a lot when running the a/c then you may need to get a technician out there.
Old 03-06-07, 12:53 PM
mjb is offline
Join Date: Dec 2006
Location: NC
Posts: 78
Received 0 Votes on 0 Posts
What type of compressor do you have? I have a Copeland Scroll Compressor that just hums away. I'm told some are louder than others. Oh well!!
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: