Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Alpine Coach Owner's Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Thread Tools Search this Thread Display Modes
Old 03-25-2010, 11:44 PM   #1
Senior Member
Alpine Owners Club
Join Date: Dec 2006
Location: Olympia
Posts: 686
Interior Noise When Air Conditioner Runs

Last fall we had our front air conditioner replaced as the old one went kaput. The new unit works well except for one problem. It is extremely loud in the kitchen area. It seems that a resonance is setting up (best guess). It is so loud next to the sink that I have to yell to talk to DW if she is next to the sink . The noise actually gets louder moving from the center line of the coach to the sink. Has anyone had this noise problem or one similar? If so what was causing it and what did you do to fix it? Any ideas on what to look for that may be causing this? Or suggestions for a fix? Thanks.

'99 Alpine Coach
Jeff and Cheryl is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 03-26-2010, 12:31 AM   #2
Senior Member
Join Date: May 2004
Location: Auburn, CA, Havasu, AZ & Mulege, BCS
Posts: 5,263
Sounds like a "standing wave" phenomenon, where sound reverb is bouncing off interior surfaces and colliding in a spot where it is additive. I took some noise measurements in my 06 when working on the AC noise and found the interior to be fairly "hard," i.e. noise hits the walls & windows & bounces back. In cases like that you can double or more the perceived sound because you get it going by, then again bouncing back, etc.

Pull the AC vent and check three things- first how tight are the screws holding the AC unit down to the donut of foam that forms the seal? If they are cranked down real hard the compressor vibration will drum on the roof. This is easier to make happen in the front than the rear where the roof is supported by walls closer than just the sides of the coach. Loosen the screws a bit at a time and see how it affects sound. You can re-tighten as needed to maintain a good seal, but sometimes an RV tech will resort to WRV'ing the screws (you can do a search for the technical meaning, basically put 400 ft lbs on a 40 ft lb fastener).

Second, dress up the wads of wiring and fasten it out of the way of the air path. This dropped 3dB for my 06. I also moved the electrical box out of the airpath; basically anything that will require the fast moving air to buffet around it will make noise.

Third, check to see if they properly aligned and taped shut the interface between the down-duct and the fore-aft plenum. These should be sealed so there is no leak of cold air into the return air path. The return air goes up and around the plenum into the AC unit's cooling coils then comes back down the down-duct. If left untaped (HD & Lowes have aluminum tape just for this chore), the cold & return air mixes in rambunctious ways making noise. Not to mention you lose a lot of efficiency mixing your cold air w/the return air.
Hope this helps.

Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project
EngineerMike is offline   Reply With Quote
Old 03-27-2010, 11:24 AM   #3
Senior Member
Alpine Owners Club
Join Date: Dec 2006
Location: Olympia
Posts: 686
E Mike,
Thank-you for the help/suggestions.
'99 Alpine Coach
Jeff and Cheryl is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Duotherm air conditioner tom49 Monaco Owner's Forum 13 07-13-2009 12:35 PM
Air Conditioner Not Working jrv 5th Wheel Discussion 5 08-27-2007 10:51 AM
Adding Air Conditioner Vette Racer RV Systems & Appliances 5 12-04-2006 05:11 AM
Extremely loud air conditioner fan noise on Kountry Star KTYSTR Newmar Owner's Forum 2 10-03-2006 03:01 PM
Basement air conditioner problem wagonmaster2 Winnebago Industries Owner's Forum 6 07-21-2005 07:13 PM

» Featured Campgrounds

Reviews provided by

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:48 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.