Carrier split A/C noises

Old 03-07-15, 04:51 PM
Thread Starter
Join Date: Mar 2015
Location: Venezuela
Posts: 9
Upvotes: 0
Received 0 Upvotes on 0 Posts
Carrier split A/C noises

I've got a challenge for anyone that knows their A/C units, specially the "split" kind.

I am having issues with my room's split a/c unit (carrier 42kce)

At complete random intervals, it starts making some noise, like water/pipe noises ending sometimes in a loud bang, so i keep getting waked up, sometimes as much as 5 times per night, some nights not at all.

I tried getting the unit serviced (just cleaning) and it didn't help.

The small pipe (drain) goes to the shower and seems to be working properly.

I can't feel or find water in the a/c unit. It's weird. Other than the noise, the unit is cooling just fine.

I recorded a whole night of noises and condensed the issue into a 2 minute audio file which i attach below. Never mind my ipod's alarm at the middle of the audio. Can you tell me what's wrong with my unit?

You should hear three types of noise. The first one is the "blowing/venting" noise. Then you will hear some kind of (water?) drops immediately following by a loud bang.

You can hear the short recording at

Any help would be appreciated!
Old 03-07-15, 06:20 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,265
Upvotes: 0
Received 0 Upvotes on 0 Posts
I didn't hear a loud bang but the first thing that I would check it the bearings in the fan. Is there any play in the fan? If it's belt driven, check the belt.
Old 03-07-15, 06:40 PM
Houston204's Avatar
Forum Topic Moderator
Join Date: Oct 2009
Location: Texas
Posts: 6,480
Received 90 Upvotes on 83 Posts
I can barely hear that recording but it sounds like defrost cycle.
Is this mini split style air handler connected to a heat pump?
Is this noise occurring in heat mode?
Old 03-07-15, 06:42 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 63,877
Received 3,749 Upvotes on 3,362 Posts
Welcome to the forums.

It's a little hard to hear on the recording but I think the unit is going into defrost mode.
Old 03-07-15, 09:45 PM
Thread Starter
Join Date: Mar 2015
Location: Venezuela
Posts: 9
Upvotes: 0
Received 0 Upvotes on 0 Posts
The first group of noises go all the way until 1:15.
Then you hear what i call "water drops" from 1:25 to 1:30
At 1:30 you hear the loud bang (and my ipod alarm) and then the cycle (first group) repeats.

I didn't have any issue recording or hearing the audio on three devices, maybe try raising your volume.

Weather in my town is about 34 celcius all year, sometimes between january and february it drops to 29-30. My a/c is set to 23 celcius, cool, high fan and i have tried setting it to medium and 26 degrees and still the noise happens, so i don't think it's going into defrost mode.

I don't use heat mode. For the one that asked about a belt, i really don't think there is one, the manual is located here

I have asked some guys and they think it's water hitting something and going back, blocking the passing of water, however i think the draining is working fine. Others said that it may be gas, not water hitting something.

On the manual i saw something regarding air purging, i don't know if it's related

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