Replace air conditioners?

[saflyer]

'05 Holiday Rambler Ambassador

I have 2 Dometic 13,500 BTU ducted air conditioners with heat pumps.  Last week while on our first hot weather trip in some time we left the coach in the morning with temperatures inside and out in the lower 70's.  The A/C's were set in the lower 70's also.  The blinds were closed.  When we returned in late afternoon the outside temp was 99-100 with moderate humidity.  The living area temp was almost 90 degrees.

I'm wondering what I should do.  Is there a test for cooling performance other than what I described?  I have been told these units cannot be recharged with coolant and the only thing to try to service them is clean the cooling coils.  Is this correct?  Are there any other options for service?

My shop told me if that didn't work the only option is purchase a new A/C.  My units, like so many are terribly noisy.  I've even thought in the past of getting new units in the hope the noise could be reduced.  That being said, are the new units known to be quieter than the ones from the early 2000's?  Replacing them would be an easier pill to swallow if I got the secondary benefit of quieter operation but I read on some forum recently that a poster replaced his with a newer model and it was louder.

How difficult is it to replace an A/C?  How heavy are they?  I'm handy enough so if it's not too complicated I could do it with a little help.  My shop can't get to me until late July and we want to take a trip before then.

Any thoughts are appreciated.

[Ivan K]

The easiest test is to measure temperature of warm air entering the unit and the air leaving the closest duct. If you get even close to 20 degrees drop, the unit works. Opposite to popular belief, the units can be recharged but at least one test port has to be brazed in. Our original units use R22 and I had to recharge one of them after I stupidly cut the line when driving into my garage. I repair car AC systems when home so I had all tools I needed to get it done. Matter of finding someone reasonable and willing to do that on the roof, versus getting a new unit. I like to keep things running if they still can and if it makes sense.

[jimc99999]

I recently switched control boards in my air conditioners when installing a new thermostat, and took the time to blow the dust out of the coils. The front AC unit had very dirty coils, both external condenser and evap coils. Previously I had thought that AC unit was must be running low on freon, since it didn't cool very well compared to the rear unit, but now it works pretty well.

I also installed new foam strips that press against the cover. The old ones were stuck to the cover, I just stuck the new ones to the top of the coils and they stayed in place. You can find the 1" high expanding foam weatherstrip in the weatherstrip section at Lowes, it installs easily. It curves well enough to follow the curve of the condenser coils with no problem. 

[dennis.mcdonaugh]

I replaced the front Penguin 13.5K AC/Heat Pump in 2016 with a Penguin II High Capacity unit and the rear unit in 2021. Both units are quieter than their predecessors, but I still wouldn't call them quiet.  I may have actually made a mistake by buying a high capacity unit for the rear because I get condensation on the first two vents when its really humid.  The unit puts out a lot of really cold air. I wasn't willing to throw money at a 16 year old unit.

[Dr4Film]

7 hours ago, dennis.mcdonaugh said:

I may have actually made a mistake by buying a high capacity unit for the rear because I get condensation on the first two vents when its really humid.  The unit puts out a lot of really cold air. I wasn't willing to throw money at a 16 year old unit.

Dennis, when parked in a really humid environment never run the fans on Auto or Low, set the fans to run on high all the time and the moisture on the vents will disappear.

Edited June 4, 2021 by Dr4Film

[Just Jim]

I replaced the unit on the front.  There is nothing really difficult except they are pretty heavy and I'd recommend having someone help you get the new unit up there.  I managed with a rope and protection on the side of the coach, but it was not fun at all.  Its been several years, but I seem to remember one of the bolts broke when I was removing the old unit, of course it had been there for 20 years.  Also, the wiring can be a problem.  My front AC thermostat also was the control for the furnace and was not compatible.  My solution was to install separate thermostats instead of a combination.