Roof Air Problams

[1985air345]

It appears that my roof A/C units (Coleman Mach) are at the end of their life. They struggled to cool the 345 in the intense 95 degree heat at a Florida beach. They both seemed to be operating at 60-70%. The rear cooled at night. The compressor seemed to kick on frequently. The bigger problem is water leaking into the coach (front and rear) from the units AND roof lining. I think the seals are shot somewhere.

I know Coleman, Duo-Therm, and Carrier make roof units.

1) Is any one unit better than the others? I was thinking about the high efficiency units since they draw less amps.

2) Are these units worth trying to repair or are they a replacement item? If so, what's the best way to get on top of the motorhome to service it?

[thenewkid64]

Fred,

I am always keeping my eye on AC prices as my 1976 Armstrong (the original), one day is gonna quit and then I will have to decide, Fix or replace?

When we replaced the Armstrong on our 77 Airstream TT we went with a Coleman beacuse we could get a 15000 BTU model. It worked well but was LOUD.

The new carrier units are aggressively priced; I have seen them at 499.99 for the 13500 BTU with the inner and outer shroud. They have some special kind of system that spays the condensate water (the stuff that runs down the outside of the MH) on the coils to help make them more efficient. The Colemans are good, but in the 660.00 range and the duo therms list close to 800.00.

Lower amperage makes sense, but with your Generator it really shouldn't matter.

Almost all RV places will recommend replacement vs. repair as the install time on a new unit is usually less than the diagnostic time on a old one. To DIY you will need an extension ladder, some plywood a few carpet scraps, rope and some help with a good back.

Pull the inner shrouds, and disconnect power and remove all fasteners that hold the system to the skin on the inside.

Place the extension ladder against the side of the coach on top of the main awning. The awning roller will distribute the weight as you climb the ladder. Place carpet scraps soft side down on the skin between the AC unit and the ladder, place plywood over the carpet. The carpet stops scratches and the plywood distributes weight. Use a wide enough piece of plywood that you span 3 or more ribs. Remove outer shrouds, remove any additional fasteners, disconnect any wiring, and pull the unit off of the roof.
After placing the unit on the plywood, tie the rope around it.


This is where the help with a good back comes in. You will be on the roof with a 100+ pound AC unit that you DO NOT want to drop. Things dropped off the top of the MH tend to bounce. Bouncing alongside the MH tends to make nasty non-removeable marks. Give the gift of old AC to your helper while you hold on to the rope. Let the old unit slide down the ladder. Once you pull it out there is no reason to be gentle with it we just want to avoid the bounce.

New install instructions will be provided with whatever brand you buy. Remember where they are so you can refer to them later.

Here is a link I have to a place that ships the Carrier for free.

http://www.rvsupplywarehouse.com/car...nditioner.html

The only drawback to the carrier is that they could bail out of the RV market and leave you stuck with a unit that is hard to get parts for. But they have been around forever, and this is a unit they build not a re-branding of someone else’s unit. Just a little food for thought.

[1985air345]

Camping World's catalog says they charge only $25 for installation. At that price, why bother doing it myself? Do they do a good job? I wonder if that price holds up for Airstream units?

[1985air345]

I wonder if my Kohler 7,000 struggles to keep both of them running since the compressors on both are running more frequently than normal?

My thought behind the high efficiency units was that the generator could run them both with some to spare while driving on a hot day (we have a few in Florida).

[thenewkid64]

Good Idea on Camping World, I forget we have one so close. I am used to having to drive 5 hours to get to a good dealer.

The reason that the kohler may be struggling is that when an AC starts to lose efficency it will draw more amperage than if it is running at it's peak. The compressor will draw more amps to create pressure, and will not stay off for long due to not running efficently. Also the largest current draw comes when the compressor starts, especially if the compressor has not been off for 5-10 min.

I am with you on the high efficency mode, not only for Generator use but also for campground use. If you can run with lower amperage, a power problem in the campground is less likely to affect you or damage your AC's.

[PeterH-79MH]

Fred, have you checked the temperature right at the unit. A good working A/C should read about 60 degrees. During a hot day the compressor will stay on continously. At night the temp control should be set down to prevent the coils from freezing up.
If it's 95 outside and humid, you are doing good getting the coach down to 80 degrees.
Have you checked you A/C drain lines, they could be plugged up and causing your leak problems.

[1985air345]

I know the rear one drains because I see it coming out of the tube above the rear tires. The front one used to drain. I couldn't find the drain tube but I need to look harder. Before I buy a new unit, I may just get up there and pull off the covers, blow out the drain line, and seal any old and cracking seals. I did have Walt's RV check it in October and he did clean out the drain lines.

It's just a pain because my AS is stored at a storage facility instead of next to my house. I also need a taller ladder.

I believe the June 1st RV Today show will talk about A/C maintenance.

[1985air345]

I'm going to buy a ladder. I put it up against the awning.

1) Do I need carpet and plywood just to take the shroud off and clean the inside? How/where should I step?

2) In choosing between Coleman and Duo-Therm, is there a drain issue? i.e. Will the new unit be able to use the existing drain hose? The Coleman SHOULD be able to. Will the Duo-Therm be able to use the drain hose? I don't want water down the outside (or the inside ).

[ALANSD]

do you mean you are going to open the awning and put the ladder up against it? I have tried to get up there with a bent 45 degree angled ladder thing, and used a 7 foot step. I still haven't quite figured on how to climb up on the roof and get back off without bweaking my widdle neck. I hope to get an 8 foot step ladder or use a scaffold I know of th dosome a/c maintenance.
Everyone says you can just climb up if you stay off the end caps.

[1985air345]

Brett recommends resting the ladder against the rolled up awning as it is strong enough to handle the load. I figure 8' is not enough to go higher than the awning with enough room to safely get down. Before I replace the A/C's, I'm going to give the units a once over.

[1985air345]

Well I was all set to run to Camping World and replace both A/C units with Coleman Mach PS units but Camping World does not have the replacement pans for Airstreams!

I did find a fin straightener do-dad at Lowes so I may just try to clean the units, straighten the fins, and caulk the pan, and clean the drain. My biggest issue is the leaking inside the coach.

I guess when these go bad I'll either replace them myself or pay through the nose to an Airstream dealer to replace them.

(I copied this to the Interior Restoration - A/C section)

[winner]

You might be interested in knowing that when I put Belle in the shop for all the extensive repairs, the air conditioners were not doing as well as they should., My mechanic got up on the roof by using a ladder leaning on the canopy cover with protection under it and plywood sheet over soft padding. We found residual bird nest material small twigs, leaves, volumes of dirt, and bent fins. He straightened the fins, removed all the dirt and detritus, charged them, and now I have two perfectly functioning air conditioners, so you are on the right track on having those serviced before you buy new ones,

[dienst1]

The air conditioner on my motorhome was toast when I bought it; the polisher/detailer that is working on it recommended the Carrier AirV unit over other units available. According to him (he has installed several for his customers) it has superior cooling capabilities and is quieter than most. The one downside to this unit is that "- Also got to make a water drip catcher for your AC, the Carriers have no drain, they need to fine tune the Fan Box!!" (his quote). He is an aluminum fabricator and has built this drip catcher before.

Our unit finally moved to the front of the queue and will be ready to pick up and drive home July 1. I'll post pictures on our website as soon as I can. In addition to the new AC we've installed two Fantastic Fans and eight AstroPower solar panels (820 watts) on the top. He modified the battery box to accept four Trojan T-105 batteries and installed a Solar Boost 50 controller; except for the AC we can power everything using solar power.

[1985air345]

I did get a ladder and got up there. Fins weren't too bad. No bird nests or bee hives. Actually not much junk in the unit. I could not figure out how to lift up the unit. The pans ripped in several places on the sides. I'm not concerned because the drainage would run down the side of the coach.

I did blast the hose up the drain and then allowed the water to pour back out. I caught the drainage in a tub to monitor how dirty it was. Lots of little stuff. I did get water back in the coach (probably from overloading the system with my hose! ). I ran the A/C's and they cooled the unit and drained out the hoses. It rained something fierce on our way back to storage and water leaked in from the front windshield. .

My 345 also started mis-firing today for some weird reason. It has never done that before. It sounded like a backfire but deeper in the engine. It' always something!

One strange thing, the unit specs one the serial # panel said 20.0 AMPs. Ummm..