Air conditioning problem

The Coleman 13.5 roof air unit does a terrible job when it approaches 90-100 degrees outside. We are lucky to have 85 degrees inside...

You are not the lone ranger. It is NOT your air conditioner.
It's the nature of the beast. An RV is nothing more than big box sitting out in the sun.

"YOU" have to make adjustments when RV'ing in real hot weather states.

1. Cover the windshield - Camco makes a good cover
2. Cover the side windows in the cab - they make ones that pop open to fit
3. Cover ALL your roof top vents - RV pillow inserts
4. Cover the windows in the coach area that are facing the sun. Slip van windshield sunshades under the day/night shades.
5. Cover window on entry door - camco makes one to fit door window.
6. If sun is on awning side drop awning to the lowest position to block sun.

7. If at all possible find parking where there are trees for shade and park 'facing' East or West. That way the sun is not hitting the full entire side of your RV in the morning and afternoon where all the windows are.

My first time in Florida I too freaked out how hot it was inside the RV with the air on. Then I learned about what you need to do to be proactive to help assist the ac and be comfortable inside.

The pillow vents alone dropped the temp inside the MH drastically. I have 3 roof vents and was amazed how much heat comes thru those and how much of your ac goes out them. The lids on those are not sealed. Covering the coach windshield and the rest made a BIG BIG difference.

And if you are in an area where the temps reach 100? You need to get a cover over the cab area too. Take a blanket whatever and cover that opening from cab to coach. I just slip the cover under the mattress on the cab over to hold it in place. THAT makes a huge dif also. One time the temps outside where so hot I also had to cover the skylight in the bathroom so much heat was coming in from there. Used removable limo tint on that!

dtappy3353; In referring to the dog house I'm talking about the tin structure that encloses the cooling coils.

2oldman wrote:

SkiingSixPack wrote:
Like others have said, the 20 degree drop is the inside air vs. the air coming out of the AC vent.

I don't agree with this.

My air gets down to the 50s, no matter what the intake air temp, but the best the temperature is going to get inside is about 20 degrees below ambient. I think that's the meaning of the 20 degrees.

Somehow I don't think 80 degree ducted air is going to do much cooling in a 100F trailer.

Am I understanding what you said ?

First worked with AC's in the early 70's and this one thing has not changed take a thermometer and measure the room temperature then measure the temperature coming out of the AC and if it is at least 20 degrees cooler then the AC is working correctly. Example the room is 100 and the air coming out of the AC is 80 it is working properly. No it does not mean that it will only cool to 80.
If you do not have to much heat gain and you are not trying to cool to large of an area for the size AC the 80 degree air will cool the 100 degree RV to 95 now you have 75 degree air coming out of the AC.
Again provided that the area that is being cooled is not to large and the heat gain is not to high the 75 degree air will cool off the 95 degree air and this process will continue to the max cooling of an AC which is approximately 65 degree air if you get colder great but do not count on it.
And as I stated one of the keys is not to let it get to 100 before you start trying to cool it off.
If you start early when it is 80 inside and the temperature climbs to 100 with the AC running and you have the 20 degree drop the AC is functioning properly then you are trying to cool to large of an area and or you have to much heat gain.

Try to camp under trees with awning out to reflect some of the heat and shad the side of the rig. Put reflective material in the windows and windshield to reduce heat coming in. Put a blanket or other barrier to contain heat in the cab area. Run the roof AC before sun can heat up the exterior of the RV.

We avoid camping or RV'ing in 90+ degree weather. Don't like being cooped up in an RV with barely adequate AC. No place like home "with all the comforts of home."

The " dog house " is the plastic thing with cup holders, etc., that covers the rear of the engine and is removable for access to the rear of the engine. The dog house has insulation inside to reduce heat from engine entering the cab area. It must be secured down properly to prevent hot air from leaking into the cab.

navegator wrote:
Get a Dometic, ours lasted 15 years in the California desert, and cooled the interior of the RV to 65 with an out side temperature in the shade of 108 degrees

Wow, that's some air conditioner.

The first problem it is a Coleman, they do not work after 85 degrees, very poor desighn.

Get a Dometic, ours lasted 15 years in the California desert, and cooled the interior of the RV to 65 with an out side temperature in the shade of 108 degrees with out having any problems until it got a leak in the condenser, the new one Dometic is just as good, we had a couple of days with 120 in the shade and inside we had 65.

Get a Dometic!

navegator

SkiingSixPack wrote:
Like others have said, the 20 degree drop is the inside air vs. the air coming out of the AC vent.

I don't agree with this.

My air gets down to the 50s, no matter what the intake air temp, but the best the temperature is going to get inside is about 20 degrees below ambient. I think that's the meaning of the 20 degrees.

Somehow I don't think 80 degree ducted air is going to do much cooling in a 100F trailer.

Am I understanding what you said ?

Throw out the anchor and put in a roof vent. Then, in the basement, add a minisplit or high wall unit. Less power, quieter, and cool air.

Like others have said, the 20 degree drop is the inside air vs. the air coming out of the AC vent.