Coleman A/C Questions

[richard5933]

Finally have warm enough weather up here to test the a/c unit which came with our trailer when we bought it last year. It's a Coleman 48203A876, which I believe is a 13.5K BTU unit (not totally sure about that).

A few questions...

1) The air coming out of the vents is barely 10-12 degrees cooler than the air going into the intake. Seems to me from reading that this should be about 20 degrees colder. Am I correct about this?

2) The condensate appears to only drain when the compressor cycles off and the coil begins to warm up a bit. A few ice crystals blew down on us once. I'm thinking that the evaporator coil is freezing up. This is a sign of a failing system, correct?

3)Whoever installed the a/c unit did it in a way which has the condensate dripping over the roof/sides of the trailer. Is there a way to get the condensate on the Coleman units to go into the drain line? It's still there under the a/c unit but not connected to anything.

4) Where does the condensate line terminate? I've found a vinyl tube exiting the driver side of the trailer just about midway down the side, just in front of the wheel well. Nothing in either wheel well. I'm guessing it's the drain line but don't know for sure.

5) If this unit has failed, is there any reason so spend 2x as much on one of the low profile units? Or, am I fine with replacing it with a new one pretty much like the old one? Are the new low-profile units any quieter?

Thanks for whatever help you can give.

[John Ware]

Three things will cause an evaporator to freeze up: Not enough air flow across the evaporator and or condenser coils or return air filter (dirty), unit is low on freon, or the drain pan is not draining correctly.

[Glenritas]

Another thing that will cause the evaporator to freeze is the temperature control is set too low , just back off the setting a bit .

[richard5933]

Any thoughts on only having about 10 degrees of temp drop between the air going into the intake and coming out of the vents? This is before it freezes, and sometimes there is less than 10 degrees of cooling.

My thoughts are that it's time to start searching for a new one.

[WhatNext]

The low temperature drop while the evaporator is freezing up indicates the Freon part of the system might be ok. So if there is a way to improve the air flow will get the cooling performance back to acceptable.

[richard5933]

Originally Posted by WhatNext

The low temperature drop while the evaporator is freezing up indicates the Freon part of the system might be ok. So if there is a way to improve the air flow will get the cooling performance back to acceptable.

Interesting, as on the troubleshooting checklists I've seen both the poor cooling and the freezing coil indicated low refrigerant. Now I am confused. The coil looks clean and air flow seems good.

I did find that the installer didn't properly trim the boot on the outlet, but even after trimming it there was no improvement in cooling.

[WhatNext]

To me the freezing evaporator coils mean they are too cold for the amount of air blowing over them. But if the air flow seems ok, the cooling coils shouldn’t be freezing up as the system is setup to work with multiple fan speeds. So unless an AC tech can cheaply fix your unit, it might be time to replace it.

[richard5933]

Right now I'm leaning towards replacing the Coleman Mach 3 with a RecPro unit (https://www.recpro.com/rv-air-condit...5k-non-ducted/).

Only two details which are causing me to pause before ordering...

1) Not sure if there is a way to get the condensate drains to flow into the drain tube on the trailer, and

2) Not sure if there is a way to install the Easy Start on the RecPro.

Pretty sure that the Easy Start can be done, but so far cannot get confirmation about installing the drain kit from a Coleman on the RecPro.

[richard5933]

Ok - nix the RecPro. Too many unknowns, so I went with another Coleman Mach 3. Nothing fancy but I was able to find one locally.