Air conditioner freezing up question

[tex_wardfan]

My trailer has an airxcel 48000 series roof top unit. My question is have any of you, who have this unit, had any problems with the evaporator icing up? I did not need to use the unit on our first trip but I'm sure I will have to on the next. The guy who made our trailer ready and gave us the walk through said we should always run the unit at max cool to keep it from icing up. I read the owners manual for the unit and this doesn't seem correct. It seems like that would make it ice up. Any thoughts on this would be appreciated.

[tex_wardfan]

smkettner wrote:
Best you can do with the selector knob is to adjust the setting to cycle the compressor if it seems to have frozen up.

It never froze up. I guess some people like to make ice cubes in their trailers and have theirs set to full cold. we were comfortable with it less than half full cold.

[time2roll]

Best you can do with the selector knob is to adjust the setting to cycle the compressor if it seems to have frozen up.

[tex_wardfan]

tpi wrote:
Sure if it works, it works-and yours may be set up absolutely correctly not to ice up. But be aware the conditions for ice up can be unusual. To be specific, a temperature which is relatively cool but keeps the compressor on for extended times.

Mine will rarely ice up at least partially. When looking into it the anti ice probe was installed in the wrong location on evaporator. These air conditioners, due to compact size and flow patterns do seem to run on the ragged edge of evaporator icing.

Even though yours worked, keep the tips in mind. You may need them someday under an unusual circumstance. If you do experience icing, keep fan speed on high, the filters spotless, and try to set the thermostat set to 72 or more (maybe as high as 75) to cycle the compressor before the ice forms.

It doesn't have a temperature selector just a knob that goes from blue to red. I set it right in the middle maybe a little to the red and the temperature in the trailer was very comfortable. You cannot hear the compressor cycle because the blower sounds like a jet engine especially on the high cool setting which is the max fan setting. It only has two speeds. Fast and semi fast its not really a low speed fan.

[time2roll]

tex wardfan wrote:
My trailer has an airxcel 48000 series roof top unit. My question is have any of you, who have this unit, had any problems with the evaporator icing up? I did not need to use the unit on our first trip but I'm sure I will have to on the next. The guy who made our trailer ready and gave us the walk through said we should always run the unit at max cool to keep it from icing up. I read the owners manual for the unit and this doesn't seem correct. It seems like that would make it ice up. Any thoughts on this would be appreciated.

If you have a wall thermostat you will have a freeze sensor. Very common for the sensor to be poorly installed. Sensor needs to be right up against the evaporator. When ice is detected it will cycle the compressor off. Very simple.

If you want to check the installation just remove the interior trim.

[tpi]

Sure if it works, it works-and yours may be set up absolutely correctly not to ice up. But be aware the conditions for ice up can be unusual. To be specific, a temperature which is relatively cool but keeps the compressor on for extended times.

Mine will rarely ice up at least partially. When looking into it the anti ice probe was installed in the wrong location on evaporator. These air conditioners, due to compact size and flow patterns do seem to run on the ragged edge of evaporator icing.

Even though yours worked, keep the tips in mind. You may need them someday under an unusual circumstance. If you do experience icing, keep fan speed on high, the filters spotless, and try to set the thermostat set to 72 or more (maybe as high as 75) to cycle the compressor before the ice forms.

[tex_wardfan]

Just got back from our second trip. Went back down to Galveston Island. Used the air conditioner almost constantly. Ran it on low fan cold setting at night. never froze up. So I guess what our make ready guy told us was wrong. He also told us that we had to run the refrigerator 48 hours before it got up to full cold. It really only took about 12 hours on both trips to make ice and keep stuff cold. He also never told us that we need to check the water level in the battery so we had an issue with it until I added some distilled water to it.

[Campinghoss]

When we had our fifth wheel the a/c would ice up when we left the fan on auto. This was not all the time only when outside conditions were right for it. Freon was perfect. We just put the fan on high, left the thermostat set where we wanted it and never had a problem again. At night we put it on auto as the a/c never froze up during the night time. I would try that before going to a whole lot of trouble checking things.

[malexander]

One time I had a brand new Coleman rooftop unit freeze up. Looked like a block of ice on top of the motorhome.
I took the inside cover down, found "a little probe" hanging loose from.......somewhere. I looked the evap coil over really well & noticed a small "hole" in the fins. I figured it was a temperature sensor to shut the compressor off if it got too cold. I shoved the sensor into the void, never had another freeze-up.

[wa8yxm]

I will explain the max cool thing.

The compressor has one speed, it always works at the same speed.

THE FAN and blower however have HI, Low and in some cases medium

MAX COOL moves more air, NOT more cold, just more air... Now this does result in a bit more cold (Since it's moving more air) but if the icing id due to low air flow.. Well more air = Less icing.

I should add. this applies to RV roof air... Dash air, (Car, truck or RV) is different, In this case MAX-COOL has to do with where the air to be cooled comes from (MAX is recirculated, regular is a blend of recirculated and fresh) ... I know, Screwy terminology but someone did write a decent joke about once. Sorry, forget all but the punch line.

[allen8106]

tex wardfan wrote:
My trailer has an airxcel 48000 series roof top unit. My question is have any of you, who have this unit, had any problems with the evaporator icing up? I did not need to use the unit on our first trip but I'm sure I will have to on the next. The guy who made our trailer ready and gave us the walk through said we should always run the unit at max cool to keep it from icing up. I read the owners manual for the unit and this doesn't seem correct. It seems like that would make it ice up. Any thoughts on this would be appreciated.

Two possibilities, you are running the AC on low speed. AC's should be run on high speed to prevent freeze up. The other possibility is a refrigerant leak. AC's that are low on refrigerant will ice up the evap coil.

[tex_wardfan]

DutchmenSport wrote:

tex wardfan wrote:
...Do you always run yours on high fan speed? Even at night?

Considering (most) of our camping is in the Northern States, nights cool down and most of the time, there's no need for Air. However, come late July and August, and it can stay pretty warm at night, and then those few times, yes, we do keep the Air turned on and windows shut.

We usually keep our AC fan on high all the time, even at night (in all 3 TT we've owned.) The thermostat stays at the same spot as it was during the day. We usually set it around 75. I'm not sure what the actual temperature is in the camper, I've not monitored the actual temperature inside, we just keep it where it feels comfortable.


Thanks again Dutchmen for addressing my question as stated and not aaauming I have a problem like low Freon. I don't even know if it will freeze up, I haven't tried it yet.

At night, as the outside temperatures cool down, and the inside temperatures stay cool, the AC will cycle on-off. More off than on after a while. Even in the hottest weather. But we don't do Southern Florida, or South Texas or Arizona in the Summer either.

Whenever possible, we turn the AC off at night and open windows. If the outside temperature is cooler than the inside temperature, the AC is off and the windows open. We also have several small fans throughout our camper to keep air circulating. When the fans and / or the AC runs (especially at night), it's like a constant white noise, which actually helps lul us to sleep. And if there are noisy neighbors, it helps drown out, outside noises.

In our first and second TT, had the roof top with the controls on the AC unit, and it was a forced air, straight down model. The fan never shut off, but the compressor cycled.

In our current trailer, it's ducked with controls on the wall, the fan and the compressor both turn off and shut down at the same time. So, actually, this is a bit more annoying, in the fact it turns on and off. And when it turns on, it usually get my attention (especially at night). We could set the thermostat so it runs on fan all the time for the steady noise. But then I also can't tell how much it's actually cycling on-off. (for some reasons, I really am in-tune with my camper. I listen for sounds and am always aware of everything going on. I'm kind of strange there. I have the same problem in my house too.

I'm in tune to everything... the refrigerator when it kicks on and off, to the water softener switching on. We have an in ground (submersed) water pump in a well 50 feet deep in the ground. For some reason, I can hear the pump when it kicks on through the sounds radiating through the floor, and .... really .... even outside when standing in the yard. I can tell when water is running inside the house when I'm outside. I hear it in the ground.

So, although constant steady sounds are a great white noise, the on-off does get my attention, probably more than most people. (funny, I've been this way all my life).

So, I guess to put a simply answer to your question, once the inside of the camper reaches desired temperature, we leave the thermostat set there, even at night, fan on high. When the temperatures are cooler outside than inside, we open the windows.

[wa8yxm]

Though I do not have that specific unit ANY AIR CONDITIOENR can Ice up if it is not properly maintained.. Some of the more common causes.

In high humidity if you run the fan on LOW or AUTO it is poissible for ice to build up during the "Down time" and not melt.

Dirty air filters can reduce air flow which can cause several issues, of which Icing is one (Niagra falls effect is another)

If the RV is not properly leveled it may cause some ice to build due to the water level in the drip tray being too deep.

If the condenser coils are clogged, the fan has to work harder and thus slows down, since the fan motor also runs the blower this reduces air flow. NOTE this will also trip breakers as the blower and compressor suck more current.

And if it is low on refrigerant it can ice up This one may (or not) be fixable.

[DownTheAvenue]

Old-Biscuit wrote:

DownTheAvenue wrote:

Old-Biscuit wrote:
MAX COOL.....

Just means uses High Fan Speed vs Low Fan Speed

Low air flow
Dirty evap coil
Dirty return filter
High Humidity

All conditions that will cause a perfectly functioning A/C Unit to Ice Up

The #1 reason A/C units ice up is low on freon!

Let me point out something for you in my post


......cause a perfectly functioning A/C Unit to Ice Up


That and the fact that OP has a NEW RV.......isn't actually 'icing up'
but was questioning statement by RV Tech to use MAX COOL

Comprehension/reading


And YES low freon will cause icing up-------hardly a perfectly functioning unit

Aren't we a little grouchy?

Nothing changes the post I made. An icing up air conditioner is usually low on freon.

And by the way, with my advanced, post graduate degrees, I am quite adept at reading comprehension, which is the term you were trying for when you typed, "Comprehension/reading."

No need to be so sensitive!

[DutchmenSport]

tex wardfan wrote:
...Do you always run yours on high fan speed? Even at night?

Considering (most) of our camping is in the Northern States, nights cool down and most of the time, there's no need for Air. However, come late July and August, and it can stay pretty warm at night, and then those few times, yes, we do keep the Air turned on and windows shut.

We usually keep our AC fan on high all the time, even at night (in all 3 TT we've owned.) The thermostat stays at the same spot as it was during the day. We usually set it around 75. I'm not sure what the actual temperature is in the camper, I've not monitored the actual temperature inside, we just keep it where it feels comfortable.

At night, as the outside temperatures cool down, and the inside temperatures stay cool, the AC will cycle on-off. More off than on after a while. Even in the hottest weather. But we don't do Southern Florida, or South Texas or Arizona in the Summer either.

Whenever possible, we turn the AC off at night and open windows. If the outside temperature is cooler than the inside temperature, the AC is off and the windows open. We also have several small fans throughout our camper to keep air circulating. When the fans and / or the AC runs (especially at night), it's like a constant white noise, which actually helps lul us to sleep. And if there are noisy neighbors, it helps drown out, outside noises.

In our first and second TT, had the roof top with the controls on the AC unit, and it was a forced air, straight down model. The fan never shut off, but the compressor cycled.

In our current trailer, it's ducked with controls on the wall, the fan and the compressor both turn off and shut down at the same time. So, actually, this is a bit more annoying, in the fact it turns on and off. And when it turns on, it usually get my attention (especially at night). We could set the thermostat so it runs on fan all the time for the steady noise. But then I also can't tell how much it's actually cycling on-off. (for some reasons, I really am in-tune with my camper. I listen for sounds and am always aware of everything going on. I'm kind of strange there. I have the same problem in my house too.

I'm in tune to everything... the refrigerator when it kicks on and off, to the water softener switching on. We have an in ground (submersed) water pump in a well 50 feet deep in the ground. For some reason, I can hear the pump when it kicks on through the sounds radiating through the floor, and .... really .... even outside when standing in the yard. I can tell when water is running inside the house when I'm outside. I hear it in the ground.

So, although constant steady sounds are a great white noise, the on-off does get my attention, probably more than most people. (funny, I've been this way all my life).

So, I guess to put a simply answer to your question, once the inside of the camper reaches desired temperature, we leave the thermostat set there, even at night, fan on high. When the temperatures are cooler outside than inside, we open the windows.