Community Forums

steve11669 · 10-04-2020, 06:33 AM

After I arrived in south Texas a month ago, 1 of 2 ac's began freezing up. It would run for a couple hours then the air would reduce until no air would come out the vent. I saw ice in the blower area. I then turn that ac off for hours and restart it and it then performs normally for hours again. The outside hunidity is a bit high in S. Texas but a few days with low humidity saw the problem continued.
The other ac has never had this problem.

What might be a remedy?
Thanks for ideas.

hypoxia · 10-04-2020, 08:13 AM

The first suspect, IMHO, is the fan motor is running slow. The only way I know to test it is to spin it and see if it coasts freely. You can weep some oil into the bearings for a temporary cure that may last months. A dirty filter or coil will also do that.

Randy125 · 10-04-2020, 08:16 AM

Usually there are two major reasons for the evaporator to freeze up is low air flow or low freon.

ga traveler · 10-04-2020, 08:28 AM

It sounds like the freeze detector has fallen out of the coil. There is a either a small metal spear that plugs into the coil or there is a larger metal round can looking clip on detector. It senses the freezing of the coil and shuts off the compressor. You can see this by removing the cover inside and checking the coil surface.
In fifteen years as service manager, I have probably ran into this fifty times or so.

TXiceman · 10-04-2020, 09:04 AM

Per above, most freeze ups are caused by low air flow. Low air flow is usually dirty filters, dirty evaporator coil, running the fan on low, or bypassing air in the unit. Low refrigerant can occur at times but is the least likely cause.

It will help others to help you if you go in to the USERS CP, Upper left hand, teal tool bar and add a signature line that list the make, model and year of the RV. It also helps to include the make and model of the item giving you the problem.

Ken

steve11669 · 10-10-2020, 08:28 PM

I haven't had much time to do anything to the ac problem. The ac in question has a ceiling duct running the length of the rig whick blocks me from seeing the evap coil or cleaning it. As soon as I have time, I will try to move the duct so I can clean and inspect the coil.

hypoxia · 10-11-2020, 06:17 AM

Quote:

Originally Posted by steve11669

I haven't had much time to do anything to the ac problem. The ac in question has a ceiling duct running the length of the rig whick blocks me from seeing the evap coil or cleaning it. As soon as I have time, I will try to move the duct so I can clean and inspect the coil.

You can unscrew the metal cover on the roof and see the evaporator.

Jon_C · 10-11-2020, 08:35 AM

A friend had this happen to them, pushing it back in the coil solved the icing problem

steve11669 · 10-12-2020, 01:07 AM

Quote:

Originally Posted by Jon_C

A friend had this happen to them, pushing it back in the coil solved the icing problem

I don't understand. Push what back in the coil?

TXiceman · 10-12-2020, 08:20 AM

Quote:

Originally Posted by steve11669

I don't understand. Push what back in the coil?

You will have to go up top and remove the sheetmetal that covers the evaporator. There is a small thermistor that should be pushed between the fins on the coil. Typically mounted low near the center of the coil. This is a freezestat and will cut off the compressor when the coil starts to ice.

The coil should not be operating that cold in the first place. Most likely the problem is low or restricted air flow. The least likely cause is a refrigerant leak and it is low on refrigerant.

Ken

steve11669 · 11-09-2020, 10:43 PM

I got up on the roof, removed the ac cover and metal shroud and acessed the coil. I cleaned it well with a brush and checked that the temperature probe is securly in the coil fins. The unit still freezes up so I think my next step will be to check the freon level. I dont know if I can accomplish that myelf or need a shop to do it.

geordi · 11-09-2020, 11:26 PM

Also check the filters - try running the unit without the inner cover in place for a bit, that will tell you if the problem is an air restriction still or if it is something else.

95% chance that there are NOT ports on the unit, so unless you are good at brazing copper, you will need an A/C tech to add the ports and then vacuum / refill the unit (it will vent when the ports are added) to get it running again. They will hem and haw about not working on an RV... But it really IS just cutting the tubing, brazing on some taps, and filling it up again like they are familiar with.

Mudfrog · 11-09-2020, 11:49 PM

OP, have you closed any of your inside vents? Have you tried running the fan on its high speed to see if that helps?

As far as getting on top and cleaning the coil, are you sure it was the evaporator coil you cleaned? I know on ours, you get to the front of the coil by removing the filter cover from inside of the motorhome. Speaking of that, you have cleaned the filter, right?

ga traveler · 11-11-2020, 07:58 AM

You do not need to have a tech braze in a fitting. Supco makes a bullet piercing valve. The part number is BPV31. It is a bolt on valve. Anyone can install it. I used one on my daughters window air conditioner and it was still working ten years later when she sold the house. We also installed several at work with zero failures. I have had several people say they are leak prone, but when pressed, they admitted they had never installed one. I installed several with no leaks.