1987 Nomad AC Blowing cold then warm then cold

[87nomaderwhat]

I have a 1987 Skyline Nomad 2440, with a Dometic AC unit that uses R22 freon. It blows semi cold air for about ten minutes or so then it changes to warm and then back to cool again and so on.

I blew out the fins.

Oh, and also the trailer was plugged into the 120v

What else can be wrong.

Please help!

I will be grateful NoMadder what.

[prolandsurveyor]

I work on havc for a living.....it could be going out on low pressure(I always put saddle valves on mine so I can check the charge but it Also could be a tstat problem.....my older units had a low medium and high settings...it wouldn't cut off the blower motor it would just cut off the compressor....

[87nomaderwhat]

well, I dont think this is the original unit because i have owners manuals for another unit that has different model numbers. also I noticed that my top cover is sheet metal instead of the plastic white cover. could this be a problem as well?

[krobbe]

If your ac unit is 27 yrs old, it very well may be worn out. Being a sealed system, no freon should be leaking out. And if it is, what is to be done about it to prevent the new freon from leaking out. The Clean Air Act doesn't allow R22 Freon to be vented to the atmosphere. This may be a problem for a repair shop's heating and cooling tech to install a tap and risk a violation. I wouldn't risk my electrical license in such a manner as it would definitely harm my lively hood.

[campigloo]

An a/c mechanic may be able to put a tap in the line.

[krobbe]

It might make sense from an industry point of view. Cheaper to manufacture, smaller footprint, and sell more units when they wear out. Plus, they are self contained unlike a home or auto unit that has external lines with connections from the condenser to the evaporator that can leak freon.

[87nomaderwhat]

well that doesnt make sense because you can recharge a car and a house but not your ac on you travel trailer! Now thats weird

[krobbe]

I was told by several RV parts places(Richfield Trailer Supply and American RV) that the ac units are sealed and are not rechargeable. I imagine they're similar to a window AC unit. I replaced one on an older MH I had. It was in the neighborhood of $400 discounted. The swap out was straight forward. They fit into a standard size vent opening. To lift the heavy things, I rigged a pulley to a rafter in my polebarn. My walls are 14ft to make that possible. Two strong guys could prob do it safely.
Here's some basic directions... Clicky

[87nomaderwhat]

Now is this something I can do myself. Can i purchase r22 and recharge the system or do i have to take it in. if so, do you have any idea how much a recharge would cost?

[CavemanCharlie]

Beachums wrote:
Sounds like you may be due for recharge.

If the compressor runs without any refrigerant it will burn up. So they use a pressure switch to stop the compressor once the refrigerant gets below a certain level. The refrigerant is being moved from the low pressure side to the high pressure side. When you are low, there is enough refrigerant to start. However, once it starts getting cycled through out the entire system, it drops below the minimum pressure needed to keep the compressor running without destroying it........
That's just my take on your symptoms

Ya, probley. I don't know if you can get them recharged anymore. Maybe if you find the right guy and you live in the right place. In the small towns around me they would probley just recomemend a replacement.

[Beachums]

Sounds like you may be due for recharge.

If the compressor runs without any refrigerant it will burn up. So they use a pressure switch to stop the compressor once the refrigerant gets below a certain level. The refrigerant is being moved from the low pressure side to the high pressure side. When you are low, there is enough refrigerant to start. However, once it starts getting cycled through out the entire system, it drops below the minimum pressure needed to keep the compressor running without destroying it........
That's just my take on your symptoms