air conditioning not working properly

I have a side mount air conditioner on my 2000 2720. The problem is that when it is 95 outside,it is 86 inside with the air on high. I even purchased a new 7500 air conditioner thinking that the old ones life was running out.
The new one is no better. I did take the screen on the outside off and actually pulled the air conditioner out so 3/4 of the air conditioner is now outside. I now can get the temp. inside down to 79 which is more bearable but not ideal. I noticed that the roof is extremely hot. When I stand up after sitting on the couch the temp. has got to be near 100.near the roof. I don't understand how anyone could dry camp in the sun. It's like being in a closed car in the sun. any suggestions on how to cool the roof down, and or why does it get so extremely hot. Thanks ken.

[mjlaupp]

1) A 7500 BTU A/C will not cool the TM to the levels you want when camping in the sun @ 95 degF. Get the biggest A/C unit that you can fit into the hole. The roof mount units are 13500 BTU. Note that changing to a roof mount unit requires major structural changes = $$$.

2) Add a fan to your camping gear. You need to circulate the cool air away from the A/C so it does not short circuit back into the unit.

3) Keep the roof as clean and white as possible to minimize solar radiation heat gain.

Mike

I heard somewhere that a well tuned and operating A/C will only have a 20F differential between the inlet and outlet temps. 7500 BTU is the load capacity of your A/C unit. I would not be surprised if the TM in the heat and direct sun adds heat back into the unit almost as quick as you take it out. The fact that you can go from 95 degrees down to 79 degrees with what you have is amazing to me. I think your A/C is working like a champ but it is limited. It is like trying to tow my TM up a mountain side with my Trailblazer 6 cylinder. It gets there but not at the posted speed limit.

Bill

Mine works about as well as yours, and it is the roof mounted 13,500 BTU unit.

When I am parked in full sun and the outside temperature is a little over 100 I can drop it down to about 80. It seems like many of us are getting a 20 degree temperature differential.

When it gets that hot, we are not in the trailer. We are either swimming or sight seeing in the air conditioned truck.

[wbmiller3]

We have the side mount A/C as well and find that using a floor fan makes a huge difference. Otherwise only the area between the a/c outlet and thermostat stays cool! Blow that cool air out into the end of the trailer and it will help.

It never gets "frosty", but we stay comfortable.

[Bill]

I agree with all that has been said above. But the obvious first step, if you can do it, is GET YOUR TM OUT OF THE SUN! Especially the afternoon sun. Choose another campsite.

In the desert, I have seen setups where the owners threw a tarp over the roof, and pushed "something" - swim noodles? - between the tarp and the roof to form air channels and encourage air circulation. The tarp was relatively small, less than the width of the roof, so as not to trap hot air. And it was held down with weights hanging from corner ropes. Must have been exciting when the wind came up. But presumably it helped, by keeping the direct sun off the roof.

Bill

I have a free standing awning that can almost straddle across the top of the TM. I keep looking at it wondering. It sure would have a nice air gap if the legs were long enough.

Thanks everybody. I put a floor fan on floor and shut the curtain in the bedroom area and I actuallly got it down to 68 degrees which is great.I also put a wet towel on top of the roof vents.I'm just mad at myself for throwing out a perfectly good air conditioner and buying a new one. ken

The 20 degree drop that is referred to here means that the AC unit has the capability to provide a 20 degree drop in the temperature of the air that passes through the AC unit, it does not mean a 20 degree drop from the outside temperature. If you have a properly sized AC unit, the inside temperature should reach a reasonable setpoint (say 72 degrees) after the unit has been running for some time and the temperature has stabilized.

If the AC unit is undersized, the 20 degree differential through the AC unit can not be expected and therefore an inside temperature of say 72 degrees cannot be expected no matter how long the unit runs.

The key here is that the AC unit must be sized to remove more BTU per hour than is gained due to sun radiation, internal heat generators such as lights and appliances, heat generated by occupants and any other internal heat source. The larger the differential between heat gained and the unit's capability to remove this heat will determine the amount of time required to reach the desired internal temperature. Obviously, if the AC unit's BTU rating is less than the heat gained in a particular situation, the desired interior temperature may not be attainable.

[Wavery]

The reason that the performance improved when you shoved the unit out of the camper is because it could then get fresh air to cool the condenser.

I am currently installing an AC unit in my 2720. I chose a 10,000BTU but the big thing is, I cut the wall out big enough to allow fresh air in from the outside to cool the condenser. I am installing separate grills for the intake and baffles to separate the exhaust air from the intake air.

This is essentially the same thing that happens when you push the unit out the side of the camper.

See this thread:
http://www.trailmanorowners.com/foru...oner#post51942