Community Forums

PORCHDOG · 07-26-2017, 01:17 PM

I have an ‘07 Winnebago 38T with basement air. It seems that the AC is not working as efficiently as it was in the past. I have had two different major RV service centers check it out in the past two years and both say it is running as it should after they tested it. We were away this past week and the outside July Florida temperature was in the 90’s. Inside the coach was 82 with four people and the front curtains open. We were on 50 amps during our stay. I must admit that the filter was dirty and I changed it. After we closed the curtains it would be anywhere from 75 to 77. I measured the inlet temperature at 78, and the register discharge at 59. The energy management system showed 23 amps when running on the generator while the tech was conducting his tests. One thing different is that two years ago our Norcold refrigerator failed so I replaced it with a Samsung residential refrigerator. I sealed and insulated the outside vents. Has anyone else had a similar experience or can anyone offer a suggestion as to what has happened to cause this change? Thank you for any help.

BFlinn181 · 07-26-2017, 01:28 PM

One of the common issues with basement A/C systems is leaking ducts between the A/C units that discharge up through the rear cap of the RV. Sealing those ducts can increase air flow and cooling.

A 19º drop is about all that you can expect, as you noted, closing curtains can dramatically increase cooling. Adding insulated sun shades, or using awnings to shade the side of the RV are also strategies that can help.

georgelesley · 07-26-2017, 01:29 PM

Depending on sun angle closing the front curtains may help. With four people and a residential refer 19 degrees difference between intake and discharge sounds right to me. 20 deg is considered normal. With the interior heat load you have what you are getting sounds about right. Maybe opening the vents behind the refer will vent some heat from the refer to the outside.

MutinyGuy · 07-26-2017, 02:30 PM

Quote:

Originally Posted by PORCHDOG

I have an ‘07 Winnebago 38T with basement air. It seems that the AC is not working as efficiently as it was in the past. I have had two different major RV service centers check it out in the past two years and both say it is running as it should after they tested it. We were away this past week and the outside July Florida temperature was in the 90’s. Inside the coach was 82 with four people and the front curtains open. We were on 50 amps during our stay. I must admit that the filter was dirty and I changed it. After we closed the curtains it would be anywhere from 75 to 77. I measured the inlet temperature at 78, and the register discharge at 59. The energy management system showed 23 amps when running on the generator while the tech was conducting his tests. One thing different is that two years ago our Norcold refrigerator failed so I replaced it with a Samsung residential refrigerator. I sealed and insulated the outside vents. Has anyone else had a similar experience or can anyone offer a suggestion as to what has happened to cause this change? Thank you for any help.

I have to agree any split of 15-20 degrees is acceptable...sounds like both compressors are running....the only thing you can do is park in the shade, insulate some of the windows, use your curtains/shades. I purchased a Magneshade for the front windshield. I think it help out a bit but nothing drastic like I was hoping for...the best part of the Magneshade is the privacy that it provides with the windshield curtains open during the day...

AFChap · 07-27-2017, 08:55 AM

When my unit output air gets down to only apx 20 degree differential I KNOW something is wrong, normally a leak in the rear duct. I routinely see a temp differential from input to output air of apx 20 degrees with only one compressor running, and 35-40 degrees with both compressors running.

As the OP found, the front window is a huge factor in hot weather comfort. In hot weather we try to avoid parking with the nose to the afternoon sun, and we keep the window covering closed when the sun is hitting the glass. We also have an additional set of fold out windshield sun shields we put behind the shades against the glass in extreme heat.

SuperGewl · 07-29-2017, 01:22 PM

You can also try opening a roof vent and turning on the fan to suck out some of the heat that is sitting along the ceiling. Your best best is to install an outside front window shade. One on the inside still allows the window to get hot and transfer the heat to inside of the MH.
AS others have said, double check all of the vents coming out from the AC up to the inside vents.
How is the actual air flow coming thru the vents? If it is weak it indicates a leak in the ducting.