Coleman central a/c unit freezing

[Rolfsted]

We usually camp in early spring/late fall so have only used the central air one time. This year we couldn't get away until first of June so we need a/c. It was fine the first few days but then started dripping from the cover. I got up on the roof and pulled off the cover and inner metal cover and one side was completely iced over. I didn't see any blockage and cleaned the filter on the cover up on the ceiling. That didn't help. I saw what looks like a valve to charge the unit but most say it can't be done.

Thank goodness the previous owner installed another a/c in the bedroom as it works fine. I do like the central unit better as it cools the whole place and shuts off just like home when the temperature is reached.

The unit is on my 1994 Tourmaster 5th wheel so I'm sure it's 20 years old.

Thanks

[Mich F]

The only time I've had an AC freeze up is when I've had the temperature setting to the max cold setting. I just don't turn it to the coldest setting anymore.

[Indy1951]

Originally Posted by Rolfsted

We usually camp in early spring/late fall so have only used the central air one time. This year we couldn't get away until first of June so we need a/c. It was fine the first few days but then started dripping from the cover. I got up on the roof and pulled off the cover and inner metal cover and one side was completely iced over. I didn't see any blockage and cleaned the filter on the cover up on the ceiling. That didn't help. I saw what looks like a valve to charge the unit but most say it can't be done.

Thank goodness the previous owner installed another a/c in the bedroom as it works fine. I do like the central unit better as it cools the whole place and shuts off just like home when the temperature is reached.

The unit is on my 1994 Tourmaster 5th wheel so I'm sure it's 20 years old.

Thanks

The most common causes are 1-dirty coils 2-dirty filters 3-blower motor not running at full rpm 4-low on refrigerant. Other causes not so common. 1-restriction in system 2-expansion valve faulty (if you have one).

[sk734]

Try running your fan on high when you use the air after you defrost it. If it has a defrost sensor make sure it is mounted at the coil to detect ice-usually at the second coil up from the bottom.

[jesilvas]

Originally Posted by Indy1951

The most common causes are 1-dirty coils 2-dirty filters 3-blower motor not running at full rpm 4-low on refrigerant. Other causes not so common. 1-restriction in system 2-expansion valve faulty (if you have one).

Spot on.

[94-Newmar]

Another way they will freeze is if the supply/return air divider has slipped out of the way or the gasket between them has failed. This allows chilled air to be drawn right back up into the unit - will cause freezing quickly.

[MnTom]

Also, the ice itself will give you an indication of what to check. White frosty ice is usually an air flow problem and hard clear ice is a plugged drain normally.

[Rolfsted]

Thanks all. The ice was clear and pretty thick on the side of the fins. First thing I noticed when I got on the roof and pulled off the cover was that there wasn't any water draining from the unit. In fact the area where it should be draining from was completely dry.

When I get it home I'll pull everything off and check it out.

[MnTom]

Originally Posted by Rolfsted

Thanks all. The ice was clear and pretty thick on the side of the fins. First thing I noticed when I got on the roof and pulled off the cover was that there wasn't any water draining from the unit. In fact the area where it should be draining from was completely dry.

When I get it home I'll pull everything off and check it out.

That tells me your drain is the problem. Hopefully an easy fix!

[Rolfsted]

I'll keep you posted

[kimbo]

looks like most people missed you saying you saw valve that looks like it was installed to charge unit. if it is charging valve then your unit might be low on ref.

[Rolfsted]

Well, that's what I thought too, but like you said nobody mentioned it.

I'll still take it apart and make sure it's clean and then see how I can get it charged.

[Indy1951]

Originally Posted by kimbo

looks like most people missed you saying you saw valve that looks like it was installed to charge unit. if it is charging valve then your unit might be low on ref.

See post number 3 item number 4 "low on refrigerant"