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Author Topic: "Basement" A/C  (Read 2502 times)


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"Basement" A/C
« on: December 08, 2014, 10:08:17 AM »
We have one of the "wonderful" basement type A/C units.  It has performed well for years but now seems like it needs some refrigerant since it does not cool as well. 

Where would you take it for this work?  I mean, do we go to a place that normally works on residential AC units?  A strictly RV A/C repair shop which probably works on roof type A/C units usually?  A Winnebago Dealer, ugh?  Looks to me like the unit has to be lowered, somehow, to get access to the needed areas.

Thx for your thoughts and comments.
07 Itasca Meridian 34SH.  '08 Jeep Sahara.
Taos, NM.


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    • The Empty Nest
Re: "Basement" A/C
« Reply #1 on: December 08, 2014, 12:47:52 PM »
The unit does have to be removed for that type service, but should never need freon added unless the sealed system has been opened for compressor replacement, or damaged somehow. Some must be dropped, while many simply slide out the side. Any competent ac tech should be able to service it if they are familiar with the standard rooftop package unit that many homes/businesses use. But they are not likely to be willing to remove it from your rv. Some service (electrical, trouble-shooting, start capacitors, etc) can be performed w/o pulling the unit. Most are not terribly complicated to pull out, and the wiring can normally be left intact so the unit can be tested etc right there.

Poor cooling could be indication that the second compressor is failing to start. The most common cause is a bad start capacitor. Poor cooling is very often caused by separated ducts behind the rear cap or at the bottom of the duct where it turns upward. That can be cured by retaping the joints which is often possible w/o having to remove the fiberglass cap.

The RV Comfort website does have a listing of service locations ...the code "uf" indicates they service the basement units, but I have found you must always call to confirm that as it is not always true.
« Last Edit: December 08, 2014, 12:49:33 PM by afchap »
Paul ... (KE5LXU), was fulltimin', now parttimin'...
'03 Winnebago Ultimate Advantage 40e
'05 Honda Odyssey toad
Escapees, FMCA, SMART, WIT


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    • Bill's Website
Re: "Basement" A/C
« Reply #2 on: December 08, 2014, 02:32:50 PM »
There is a Basement A/C Removal procedure in the Library section of this forum that I wrote 6 yrs ago and many members have found it quite useful.  The illustrated photos give a step-by-step procedure and tips on replacing the problematic brass bearings with ball bearings, outdoor blower metal squirrel cage, cleaning, etc.

When my #2 compressor lost all the freon due to the #1 compressor rubbing a whole in the line, I pulled it out and on a bench.  I had the lid of, so the mobile a/c guy could work on it and test.  He did have to add schrader valve and was done with the whole repair in 45 min.  Total cost for freon and his time was $115.   If you can locate a mobile a/c guy that works on refrigerated  truck/trailers you may have a winner (and you pull the unit yourself).

Checkout the link to procedure here:
Good luck,
« Last Edit: December 08, 2014, 02:34:49 PM by Duner »
Bill & Helen
2004 Chieftain 39T W22 -- "The Last of the Chieftains"
Toad: 2017 Lincoln MKZ Hybrid

John Hilley

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Re: "Basement" A/C
« Reply #3 on: December 08, 2014, 07:05:30 PM »
You may only need to clean the condenser. Also check your filter.
2003 Winnebago Adventurer 38G
1999 Jeep Cherokee Sport
1999 Winnebago Brave 35C
  Handicap Lift & Hospital Bed


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Re: "Basement" A/C
« Reply #4 on: December 10, 2014, 07:33:55 PM »
I just went through the same thing back in September. It started with with the A/C not keeping up with cooling the coach, was putting out 75 or so out of the vents before she gave up the ghost. I opened up the access door to the A/C and removed the cover from the electrical panel to see if there was any obvious signs of burned up or broken components. Saw that one of the jumpers wires was corroded and the start motor on one of the start capacitors was burned up. The second cap and it's associated starter were looking okay, however, i ended up replacing both and ordering spare capacitors just to have on hand. The caps are readily available and easy to find on line, however, the "starter motor" not so much. I found a kit on amazon and ordered it and replaced both sets on the A/C unit. Also replaced the jumper wire with one of the extra wires i didn't use from one of the kits. End result, got cooling and unit was putting out 42 at the bedroom vent with an outside temp of 65. Here's the link to the kit for cap/starter device on amazon:
Hope this helps out.
2000 Ultimate Freedom 40JD


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Re: "Basement" A/C
« Reply #5 on: December 10, 2014, 08:50:01 PM »
When you drop the unit out check the seals where the AC unit contacts the duct, mine were old and crumbly so I replaced them with some closed cell neoprene foam insulation
Will and Jane
95 Winnebago Luxor


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Re: "Basement" A/C
« Reply #6 on: December 11, 2014, 08:23:17 PM »
I have the basement air in mine also and went through all the motions to check cooling just as it sounds like you are. Found that I didn't have a problem, just overwhelmed the unit so you might check all the simple stuff to verify if you actually have a problem. Look at your monitor panel to verify that both comp are coming on by the amp draw. You should see the 15a then around 22a when the 2nd compressor kicks in.
Mine has the fresh air intake filter by the side of the bed, make sure it is clean.
Start early in the day before it gets overwhelmed and with both compressors running check the air temp coming out of one of the bedroom ducts. Mine would easily show a 20+ degree difference than ambient. If you are close to these temps then you prob don't need freon. If you do need to add freon then a tech will prob have to add the taps like Duner as mine didn't have a place to add more freon either.
You can also get under the rig in the back and look up at the ductwork to make sure it is still reasonable sealed up as other have suggested.
In the end mine was working fine, we were just in an area without shade, high temp & humidity and the unit got overwhelmed so we had to deal with it until we could get some more shade. I have heard some have added another roof air unit to help if they are in high temp areas often where the basement air gets overwhelmed. Good luck with it.

2009 Tiffin Allegro Bus 43 QRP
Powerglide Chassis, 425 Cummins, Allison 6 Speed
2010 CRV - Blackhawk 2 - Air Force One
2002 Heritage Classic
Washington State