Roof top A/c not able to keep up.

[Marchos77]

My Allegro rooftop A/C unit up towards the front is having a hard time keeping up in this hot weather.  Right now the thermostat is set to 78 but at the moment its 87. The rear A/C works like a champ and it gets cold back there.  Anyone have any suggestions as to what might be the issue?  I wish I could get up top and check it out but the ladder on the back of the RV only holds 220lbs and I am about 100 over that.  It runs and when the day cools down it get cold but only at night.  Seems that during the day unless its shaded it can't get the temp down below 80-85.

 

[darsben]

can you stick a thermometer in the cold air outlet  and get a temp reading?

20-25 degree difference is the best to expect.
Could be you need to clean the coils

 

[Marchos77]

Probably what I need to do. How much weight can the roof support? Also, has anyone come up with another method of getting on the roof of the bus without using the rear ladder?

 

[darsben]

If you hand and knee it to the area you need to go you should be okay.
Does anyone near you  have an extension ladder?

Do you have a good mobile rv mechanic?

 

[Utclmjmpr]

Have you ever stopped to think of where most of the glass in the coach is located??  Cover as much as possible,, use window awnings and any other form of shade possible.>>>Dan

 

[Marchos77]

Have you ever stopped to think of where most of the glass in the coach is located??  Cover as much as possible,, use window awnings and any other form of shade possible.>>>Dan

You have a good point. There are several windows in the area in question but we have thrown out the awning and closed all the shades in the room.  Still gets pretty hot.  It has been over 100 degrees here so its stands to reason that it would not get better than 20 degrees from high which today and tomorrow will be 110.

 

[cadee2c]

I had the same issue with my front a/c a couple of years ago. Mechanic went through and cleaned out all the vents and stuff but it just wast able to cool the room. I ended up replacing it with a new one. However, even now, it doesnt work well in the direct sun if the outside temp gets up to 90. Do what Dan suggested, cover the glass.... on the outside if possible. That should help tremendously.

 

[Arch Hoagland]

cadee2c said:

". on the outside if possible. That should help tremendously."

I agree....covering the outside has worked better for us.

 

[John From Detroit]

One thing many overlook is cleaning the condenser (outside) coils.. Sometimes they need it.

Same for the inside filters.  Note I said SOMETIMES.

 

[Gary RV_Wizard]

The windshield is the huge sun & heat hole in the front of any coach. If you haven't covered that, preferably with a reflector, covering windows isn't going to change much. Also the rooftop skylights, if any. And finally, all the windows up front.

I personally think that cleaning the roof top a/c fins is vastly overrated as a solution to most any RV a/c problem.  The more sensitive area is the air filter and the inside heat exchange, where the interior air blows over the chiller.  You should check the effectiveness of that part of the system by taking air temperature measurements at the room air intake and the first available cold air exit. The difference should be 20-25 degrees if ithe a/c is working as designed.  If less than that, you will need to dig further into the a/c internals, but if it meets that criteria than forget about any further cleaning or repairs cause it is doing all it can ever do.

 

[sightseers]

in most every RV....if it's 100+ degrees outside.

  80 degrees inside is about all you can hope for.

 

[Marchos77]

Thanks for the info. I will try that.

 

[House Husband]

The condenser is an important part of the system. It's responsible for transferring ALL the heat in the system to the outside air. Any contanament on those fins greatly reduce that capacity. You can blow out the fins with a water hose or compressed air. Just make sure the air flows freely through the fins. A little Dawn will help also.

 

[johnhicks]

  My a/c runs around 10F under summer ambient. That said, the thermometer in the shade indicates 95F and the indoor therm indicates 84F. However,  the entire length and breadth of the MH is exposed to direct Florida sun all day. That's about as good as it gets for a heat-soaked RV.

  It was better in Texas when we had a steel pole barn.

  Don't expect more than reasonable.