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Old 08-11-2008, 02:23 PM   #1
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recharging the A/C

Hello I just purchased a 86 1550 and the only thing I can find an issue with is the A/C. Is it easy to refill the freon? I have done it to my truck but never to a camper type A/C unit. Do I have to take it to a shop? Is it even possible to recharge it? Any help would be greatly appreciated.


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Old 08-11-2008, 03:20 PM   #2
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Hi Willie,

From what I'm told, it isn't possible to recharge the AC units. They have to be replaced. I don't know the age of the AC unit itself (AC was a very rare option from the factory, later added by a dealer/owner), so at this point, if it's really old, you may want to replace it with a new more efficient model. It would probably cost around $800 for a replacement.


2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR
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Old 08-11-2008, 04:29 PM   #3
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I'm not sure about your air conditioner, but I was able to recharge the A/C on my Airstream and it was a 1975. And my buddy had the A/C on his pop-up done once also. I'm assuming that your A/C is a Coleman Mach II unit, which is what I'm thinking Sunline used in that time frame. You can have any knowledgeable HVAC tech take a look at it, and he could tell you wether it's worth it or not. Sometimes you only need a few ounces of freon for the unit to regain normal operation. To do it properly you need a set of guages to get the proper reading, and depending on the type of freon they may have to vaccuum pump out the old stuff and replace it with the new style. My buddy (who is a HVAC tech) gave my Airstream a few ounces of freon in a matter of minutes.
Also, before you go to all of the trouble, make sure you are getting the proper voltage to your trailer. You can buy a voltmeter that plugs into one of your trailer outlets at most RV dealers for about $15, I'd reccomend this anyway. If you arn't getting full voltage to your coach the A/C won't work properly, and you can easily burn out your fridge element too. I always keep an eye on the voltmeter. Hope this helps.
Lowell, Amanda, Marley, and Winnie
1996 T-2053 (First Sunline "Little One")
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Old 08-12-2008, 02:27 PM   #4
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Rich Nagel
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I'm not sure about one that old (mine is a 1991 Sunline Solaris T-2490 - see link in my sig below <G>), but the freon system in most semi-modern rooftop ACs is a sealed system. On a home AC the system has "Schrader" (sic???) valves (sort of like an automobile tire air valve) that an AC tech uses to attach his guages, freon jug, etc... but most RV rooftop units don't have the Schrader valves.

Now, that isn't to say that it can't be recharged. With the proper equipment, an AC tech (or someone with knowledge in this area) can drain the system, sweat in (weld) two Schrader valves (one for the suction line (low pressure side), and one for the discharge line (high pressure side)), and then vacuum and charge the system.

I myself have done the above last year, as I used to work in the AC trade, and had access to a vacuum pump, guages, and freon. I also had Dometic send me a service manual (which listed the proper pressures/freon amount). Hehe, my rooftop unit had developed a leak on the suction line, due to a bundle of wires that feed the blower motor rubbing against it for many years <G>. I had previously joked with my brother-in-law about it (who is still in the AC trade, and who loaned me the equipment to do the job)... "Here! You are in jail, and here is a piece of fiberglass wire insulation... Now, saw your way out!" <LOL>!

Anyhow that, in combination with cleaning the evaporator and condensor coils breathed a bit of new life into my old rooftop unit - Plus, the Schrader valves that I installed allow me to check system freon pressures, or add more if the need arises.

Anyhoo... not a simple process, unless you're experienced in copper welding, and have access to the equipment (guages, torches, freon, etc...).

P.S. You can clean the evaporator coil using "Simple Green", and the condensor coil using one of the commercially available foaming condensor coil cleaners (I bought a can at Home Depot, but don't remember the brand name of the cleaner offhand). Use a foaming cleaner that doesn't need to be rinsed off though.

P.P.S. Note that a rooftop (or home) AC unit doesn't use the same type of freon as an automobile's AC system, and unless you're brother-in-law works in the AC trade <G>, you might have a problem getting freon.

One problem that I ran into with my rooftop unit, was that absolutely NO ONE (RV repair places, home AC service places, etc...) wants to work on them, but rather opt to "Well sell ya a new one!"...


A) Wasn't an option ($$$),


B) A total waste of money, when all I needed was to vacuum and recharge the system.
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Old 08-12-2008, 04:09 PM   #5
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Great post Rich. Thanks for the info
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Old 09-18-2008, 05:41 PM   #6
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Thanks all for the info I really appreciated it. I have a friend thats an A/C guy. He came over and helped me out. Shes working fine now.

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