Air conditioner

I have a 26 foot towable trailer that has a 13,500 BTU AC unit. The unit blows cold air but I think it should be a lot colder. For example, there are four in the family and when we are all in the trailer, with the outside temperature in the high 80's or 90's it is really quite uncomfortable. Am I expecting too much?
I took the cover off and carefully cleaned the unit but didn't seem to help.

What am I missing?

RE: Air conditioner

travel trailer a/c systems are factor sealed. A good place to start is to check to spilt which is the return air temp at the filter and the temp at your output grill. This should be around 15 degrees differences . One other thing you should check is the suction line off the compressor up top at the unit. This would be the big line coming off the compressor it should be cold to the touch and sweating. Your unit should also be draining condensation off the roof. If you have to have gas added they will have to take out what is in it if any and put values in to charge the system. This could get expensive might be just better in that case to upgrade to a 15000btu. Hope for the best .


Senior Member
Re: Air conditioner

The standard for inlet temperature to outlet temp. change for a Dometic air conditioner is 18 degrees, minimum with 22-24 considered to be normal. A single air conditioner of 13,500 BTUs is not great for a trailer that is 26' long. You don't say just how well insulated the RV is nor if you have dual pane glass in the windows, but those also make a major difference in how well it will cool.

To check the temperature change through the cooling unit you need to have a good dial thermometer. First, place it in the inlet side of the air conditioner where it draws air into the coils. Allow it to stay there for at least 5 minutes. Read that temperature and then move the thermometer to the outlet side and wait for it to settle out, probably another 5 minutes or so. I would expect somewhere above a 15 degree change, 20 or more if the unit is in good condition. If it isn't that much, you probably need to clean the coils both on the outside and also the coils inside that cool the air. Both need to be clean and in good condition to have proper cooling.

The fins on the radiators also should be straight and if they are not, there is a comb that can be used to correct that. If this is good, next check the air passages for leaks. I would use the metal type of duct tape to seal any cracks or openings where outside air could be entering the interior from the inside blower. Keep in mind that there are two blowers, one to cool the outside coils to disperse the heat that is being removed and the other moves inside air through the cooling coils.

If you get the proper amount of cooling but the interior of the trailer is still not comfortable, look for air leaks where outside air is getting into the trailer. Anywhere there are openings for wires or pipes could be a source of hot air and thus should be sealed. The expanding foams are a good thing to use for such leak prevention.

Shade for the RV will also make a major difference in how well the unit is cooled. There is a significant heat gain through the roof and windows if the RV is sitting in direct sun.

Part of the issue is also what make and quality the RV is. Poorer quality RVs are always more difficult to keep warm or cool. How well insulated is the RV? What is the outside temperature that you are dealing with?