A/C FREEZING AND MAKING ICE

[RSPECT]

Hey y'all,
So we have a Cyclone 4005. A few months back while we were camping the a/c in our master bedroom built up ice in it so I shut it off and never used it again. This past weekend while camping again, the living room a/c sounded like it was creating ice as well. I shut it off and tried using the bedroom a/c and it worked fine with no issues. I am having a feeling they are low on coolant. The question is has anyone recharged the a/c themselves? Is it fairly a straightforward procedure? Or is it something we HAVE to take it to a repair shop to get done?

BAMA

 

[Dahillbilly]

RV a/c units do not come with charging ports, Make sure you have good air flow & set the thermostat on AUTO not low or high and see what happens. Also above in the TOOLS tab- User guides you will find lots of infomation on this topic among other topics.

 

[RSPECT]

RV a/c units do not come with charging ports, Make sure you have good air flow & set the thermostat on AUTO not low or high and see what happens. Also above in the TOOLS tab- User guides you will find lots of infomation on this topic among other topics.

I'll see what else I can find in the guides but I do "believe" there is good air flow. The reason I asked about filling the coolant is because I have read in a lot of places that low coolant can cause the freezing or making of ice. As far as the thermostat goes, mine does not offer a high or low option, you just turn the fan, heat, or in this case a/c to on and set the temp and that's it. I have tossed the idea around a lot of changing out the thermostats to allow more control.

 

[wdk450]

I wonder if the "ice sensor" that clips on the cooling coils and disables the compressor when the temperature in the coils gets too low is missing, or not clipped in place.
See Page 9, paragraph G of this document for more info :

https://manuals.heartlandowners.org/manuals/Heating-Cooling/A-C_Units/Dometic/Brisk-Air-AC_installation_EN.pdf

 

[RSPECT]

I wonder if the "ice sensor" that clips on the cooling coils and disables the compressor when the temperature in the coils gets too low is missing, or not clipped in place.
See Page 9, paragraph G of this document for more info :

https://manuals.heartlandowners.org/manuals/Heating-Cooling/A-C_Units/Dometic/Brisk-Air-AC_installation_EN.pdf

Thank you. I will definitely check that out!

 

[hoefler]

Make sure the filter is clean and the evaporator fins are clean as well. High humidity and running the fan on low will also make it more prone to freezing up.

 

[david-steph2018]

We had an air conditioner unit on our old freeze up while in Washington D.C. once. Issue was low voltage in the campground, as it was hot and allot of rigs were running all A/Cs to stay cool.

 

[RSPECT]

We had an air conditioner unit on our old freeze up while in Washington D.C. once. Issue was low voltage in the campground, as it was hot and allot of rigs were running all A/Cs to stay cool.

That's interesting. I don't "think" it should have been a voltage issue this time because I was on my generator and didn't have anything else running. But ya never know! I'm going to be checking the freeze indicator as mentioned above just to make sure it's in place correctly and hasn't fallen out or anything. I'll also check the voltage on the unit with the generator running to make sure I don't have any electrical issues. Thanks for the heads up.

 

[centerline]

if its building ice, its not low on fluid.... with the RV ac units, building ice is a normal thing when the airflow is low, or the humidity is really high.... its NOT desirable, but it happens.

after insuring the fins and air ducting is clean and allowing for maximum airflow, the only thing you can do is to turn the temp setting UP a little so that the unit will cycle off more often, giving it a chance to melt any ice that begins to form....

there is a happy medium somewhere that you need to find by experimenting.... there is a dynamic balance of humidity, airflow, desired temp and actual temp that has to be met to get the best cooling action from an RV AC unit, and these conditions can change thru-out the day and location....

most people usually just turn the AC on with a low setting and let it do its thing, but this does not always offer the best cooling, because as the unit runs for a long time it begins to build ice (long before we notice it) and begins to become less efficient.... and as the ice cube grows, it restricts the airflow more, decreasing the capacity to cool the RV.... as the ice still continues to grow until the airflow is blocked.

when the happy medium is found, the airflow will keep the moisture that is drawn out of the humid air from forming into ice, and will drain out of the AC uint as water....

in hot humid areas, setting the ac to about 75 usually gives better results, as the unit will properly cycle enough that it keeps the airway free of ice, and giving the air a chance to cool as it passes thru the unit.... YES, we want COLDER, but its just not possible when the unit starts to build ice....
and YES, they could build a more efficient AC unit for RV's, but to build one big enough to prevent the usual problems that we normally encounter WHEN the conditions are right to cause these problems, the unit would need higher voltage and be so big and bulky as to make it impractical as a mobile rooftop unit.... so we just have to find a way to run what we have within the parameters of its ability to cool in different atmospheric conditions.......

 

[RSPECT]

if its building ice, its not low on fluid.... with the RV ac units, building ice is a normal thing when the airflow is low, or the humidity is really high.... its NOT desirable, but it happens.

after insuring the fins and air ducting is clean and allowing for maximum airflow, the only thing you can do is to turn the temp setting UP a little so that the unit will cycle off more often, giving it a chance to melt any ice that begins to form....

there is a happy medium somewhere that you need to find by experimenting.... there is a dynamic balance of humidity, airflow, desired temp and actual temp that has to be met to get the best cooling action from an RV AC unit, and these conditions can change thru-out the day and location....

most people usually just turn the AC on with a low setting and let it do its thing, but this does not always offer the best cooling, because as the unit runs for a long time it begins to build ice (long before we notice it) and begins to become less efficient.... and as the ice cube grows, it restricts the airflow more, decreasing the capacity to cool the RV.... as the ice still continues to grow until the airflow is blocked.

when the happy medium is found, the airflow will keep the moisture that is drawn out of the humid air from forming into ice, and will drain out of the AC uint as water....

in hot humid areas, setting the ac to about 75 usually gives better results, as the unit will properly cycle enough that it keeps the airway free of ice, and giving the air a chance to cool as it passes thru the unit.... YES, we want COLDER, but its just not possible when the unit starts to build ice....
and YES, they could build a more efficient AC unit for RV's, but to build one big enough to prevent the usual problems that we normally encounter WHEN the conditions are right to cause these problems, the unit would need higher voltage and be so big and bulky as to make it impractical as a mobile rooftop unit.... so we just have to find a way to run what we have within the parameters of its ability to cool in different atmospheric conditions.......

Well.....that's not the answer I wanted to hear because we are definitely one of those couples that likes it COLD when we're in the camper! lol I will experiment with the temperatures next week. The difference right now is the change in temp. We've dropped about 10 degrees since it was freezing over. That's good in two ways. 1, we won't need to run it as much and 2, when we do run it we won't need to drop it so low. The two times they have built ice happened when it was pretty humid as you mentioned. We're down in Alabama which is regularly hot and humid so this is making sense. I am feeling much better about the problem though. Thanks for the info!

 

[centerline]

Well.....that's not the answer I wanted to hear because we are definitely one of those couples that likes it COLD when we're in the camper! lol I will experiment with the temperatures next week. The difference right now is the change in temp. We've dropped about 10 degrees since it was freezing over. That's good in two ways. 1, we won't need to run it as much and 2, when we do run it we won't need to drop it so low. The two times they have built ice happened when it was pretty humid as you mentioned. We're down in Alabama which is regularly hot and humid so this is making sense. I am feeling much better about the problem though. Thanks for the info!

its kind of a "catch 22".... the air mass of a cooler atmosphere does not hold as much moisture as warmer air can..... so, when you need your AC the most (hot, humid weather), that is when its least efficient.....

play with the thermostat settings for awhile, you will find that you can get the inside of the trailer cooler with the thermostat set at a warmer temp than you have been using...

now that you know what causes the ice to build and what to watch for, you will find that sweet spot on the 'stat that allows the AC unit to run as long as it can, and then just before it starts to build ice, the compressor cycles off to allow any ice crystals to melt, and then kick back on to resume its cooling action...... as long as the AC circulation fan inside the coach runs, there should be no noticeable difference in the temperature of the air exiting the AC unit, no matter if the compressor is running or has cycled off for a few minutes...

one thing to remember is, the "sweet spot" of the thermostat WILL change with outside temp and humidity changes, so its a good idea to keep a journal for awhile until you see where it works the best at different temperatures.... eventuallly you will get to where you can quickly "set it and forget it" for maximum efficiency at any given temperature.....

 

[sengli]

Thought I read somewhere a while ago that the normal operating routine for RV AC's is they are only good for efficiently cooling a unit approximately 10 degrees below ambient.

 

[RSPECT]

Thought I read somewhere a while ago that the normal operating routine for RV AC's is they are only good for efficiently cooling a unit approximately 10 degrees below ambient.

If that were true, wonder if 3 a/c units would equal 30 below ambient? I just need them to work and cool it enough for us (my wife) to be comfortable at night. We're outside most of the day so it doesn't matter then. Unless we're going somewhere the dog can't go then I leave her in the camper with the a/c running.

 

[2019_V22]

SO when an AC unit freezes up, there are several reasons. Low refrigerant, a low refrigerant charge will cause excess frost and some ice depending on how long it's been running. Usually the frost/ice pattern will encompass some of , or most of the coil, not all of it. A bad, misreading, or improperly mounted ice sensor may allow the unit to run to the point of frost over, this will usually present as most of if not all of the coil on a properly charged system covered in ice or frost. Poor air flow will do similar as the ice sensor, poor airflow can be caused by a dirty filter, and or a dirty evap coil. The evap coil can accumulate micro dust that passes through the filter, in addition to mold and mildew congesting the fins of the coil. High humidity may play a part of excess frost/ice, but an AC's job is to remove moisture in the first place, which may suggest a return air leak to the coil. Also, most of out cool only units are fixed metering of the refrigerant done with capillary tubes, this only allows a unit to cool at one level of effiency if you will. This would be apposed to a variable metering device like a TXV (thermal expansion valve) which will vary the amount of refrigerant to the evap coil and therefore help reduce frosting over. AC roof top units mainly today, and somewhat in the past do not have service ports. An inexperienced layman would not have the correct knowledge in the proper refrigerant charge, and or proper pressures. The main reason there are no ports in today's equipment is because of the R410A refrigerant, it operates at a much higher head and suction pressure. Improper charging of this refrigerant can cause something like the compressor terminals to blow out, this would extremely dangerous.
Charging is possible by a qualified tech. R410A refrigerant is a BLEND refrigerant, there is more than one compound used to comprise the final product. If there is a leak in the system, no matter the size, the refrigerant will leak out in unequal portions, at which some point what's left can no longer saturate and sub cool the evaporator. If a leak is suspected, a leak check must be identified first. If a leak is found, all the remaining refrigerant must be removed (recovered) for recycling, the repair made, and a fresh virgin charge added by weight only. See my post in the Terry forum linked below.

https://heartlandowners.org/threads/a-running-list-of-corrections-mods.74358/page-5#post-662848

 

[RSPECT]

SO when an AC unit freezes up, there are several reasons. Low refrigerant, a low refrigerant charge will cause excess frost and some ice depending on how long it's been running. Usually the frost/ice pattern will encompass some of , or most of the coil, not all of it. A bad, misreading, or improperly mounted ice sensor may allow the unit to run to the point of frost over, this will usually present as most of if not all of the coil on a properly charged system covered in ice or frost. Poor air flow will do similar as the ice sensor, poor airflow can be caused by a dirty filter, and or a dirty evap coil. The evap coil can accumulate micro dust that passes through the filter, in addition to mold and mildew congesting the fins of the coil. High humidity may play a part of excess frost/ice, but an AC's job is to remove moisture in the first place, which may suggest a return air leak to the coil. Also, most of out cool only units are fixed metering of the refrigerant done with capillary tubes, this only allows a unit to cool at one level of effiency if you will. This would be apposed to a variable metering device like a TXV (thermal expansion valve) which will vary the amount of refrigerant to the evap coil and therefore help reduce frosting over. AC roof top units mainly today, and somewhat in the past do not have service ports. An inexperienced layman would not have the correct knowledge in the proper refrigerant charge, and or proper pressures. The main reason there are no ports in today's equipment is because of the R410A refrigerant, it operates at a much higher head and suction pressure. Improper charging of this refrigerant can cause something like the compressor terminals to blow out, this would extremely dangerous.
Charging is possible by a qualified tech. R410A refrigerant is a BLEND refrigerant, there is more than one compound used to comprise the final product. If there is a leak in the system, no matter the size, the refrigerant will leak out in unequal portions, at which some point what's left can no longer saturate and sub cool the evaporator. If a leak is suspected, a leak check must be identified first. If a leak is found, all the remaining refrigerant must be removed (recovered) for recycling, the repair made, and a fresh virgin charge added by weight only. See my post in the Terry forum linked below.

https://heartlandowners.org/threads/a-running-list-of-corrections-mods.74358/page-5#post-662848

I've got a lot of info to work with now. I'll be able to look at the a/c's this weekend and hopefully come up with a plan. Thanks for the info.

 

[RSPECT]

OK, spent the weekend with the camper tailgating and didn't have any issues with the A/C's. I did notice that it wasn't hardly humid at all. Second, I removed the bottom cover of the roof a/c just to kind of keep an eye on what was going on which I'm sure helped with air flow but removes the return filter so I don't want to do that often.

I'm leaning to the problem was high humidity and possible air flow issues. I'll be back in it in a couple of weeks so I'll clean all the filters that trip and hopefully we're all ok! Thanks for all the ideas that were given!