A/C freezing up, and not cooling.

[AndyK]

We have a used 2015 Lacrosse 329-BHT we just bought. Last week I plugged it in Wednesday afternoon to prepare for our trip this weekend. The A/C was really struggling (It was about 93-95° with the humidity it felt like 103-105°), and froze up. Dropping some ice through the vent on to the floor. It also seemed to stop working completely, but no breakers we're popped. I just turned it off, then back on, and it came on, and ran. Now I also went up, and checked the coils. They weren't that bad the evaporator coil was really clean. The condenser coil was a little dirty, but I cleaned them both anyway. Also the sensor is in the evaporator coil, and working that shuts the compressor down when froze up. This weekend we were in the mountains maybe 73-80° tops. Barely any humidity. It still struggled, and froze up. Any ideas. Am I missing something? It's going back tomorrow to the dealer to get this, and a couple minor things fixed under warranty. He guarantees them for 90 days after thier bought regardless, and said he would take care of it.

[uncbearfan]

Could be a block in the duct somewhere? Are all of your vents completely open? I've also read it's better to set the fan to HI rather than auto to help reduce freezing up.

[AndyK]

Originally Posted by uncbearfan

Could be a block in the duct somewhere? Are all of your vents completely open? I've also read it's better to set the fan to HI rather than auto to help reduce freezing up.

I tried it running through the ducts, or dumping directly out the vent. Froze up both ways. Froze up faster going through the ducts. Also ran it on Hi, or auto still froze up.

[DavidBo]

Two things cause air conditioner evaporator coils to freeze up. The most common is inadequate air flow from a dirty filter, clogged coil or weak fan. If all that's good then a low refrigerant charge is another possibility. Your unit is pretty new so that seems unlikely in a hermetically sealed system, but possible. If you run it with the cover off (mind the fan!), the high pressure (small diameter) line leaving the compressor should be very hot, and the larger return line will be quite cold. If this isn't the case, you could have a slow leak and lost refrigerant. That means a trip to the service department.
Good luck!

[str8t six]

if its freezing up with the fan on all the time, then it is probably leaking refrigerant and thats why its freezing up.

[AndyK]

Originally Posted by str8t six

if its freezing up with the fan on all the time, then it is probably leaking refrigerant and thats why its freezing up.

That's what I was thinking. I put it on auto last night after it cooled down, and switched it to run through the ducts. My daughter said she heard ice fall off, and hit the vent when the unit kicked on.

[Witch Doctor]

Originally Posted by AndyK

That's what I was thinking. I put it on auto last night after it cooled down, and switched it to run through the ducts. My daughter said she heard ice fall off, and hit the vent when the unit kicked on.

Your low on Freon, sounds like to me, there are no ports to put gauges on, can you just run the fan and see if your getting good air flow, If you are it's differently a low Freon problem, they will have to change it out....

[Super Flag]

As noted in your initial post, you have made all the preliminary checks as to the icing problem. A dirty evaporator coil, a bad or misplaced sensor that controls the compressor's operation. A low charge of refrigerant is a great possibility. As noted by the Witch Doctor, a unit that is low on refrigerant means a new condensing unit. Low performance (no icing) is indicative of a dirty condensing coil. Some of the newer units use a 410A refrigerant which operates at a higher pressure. Higher pressure operation can attribute to leaks with the thinner wall copper tubing that is used now-a-day in refrigeration units, especially those made in China. Let us know what the dealer has to say about the unit. Please don't buy into a quick fix by an inexperience dealer's tech that is now schooled on A/C units.

[AndyK]

Originally Posted by Super Flag

As noted in your initial post, you have made all the preliminary checks as to the icing problem. A dirty evaporator coil, a bad or misplaced sensor that controls the compressor's operation. A low charge of refrigerant is a great possibility. As noted by the Witch Doctor, a unit that is low on refrigerant means a new condensing unit. Low performance (no icing) is indicative of a dirty condensing coil. Some of the newer units use a 410A refrigerant which operates at a higher pressure. Higher pressure operation can attribute to leaks with the thinner wall copper tubing that is used now-a-day in refrigeration units, especially those made in China. Let us know what the dealer has to say about the unit. Please don't buy into a quick fix by an inexperience dealer's tech that is now schooled on A/C units.

I agree.

[AndyK]

Update.....

I dropped the trailer off today, and talked to the tech. The one thing he said he needed to check was to see if the cold air was leaking through the divider into the return side. He said this would cause it to freeze up, and low volume out of the ducts. I asked about a obstruction in the ducts. He said that he would check, but most of the time that's not the case with a newer RV. The RV ducts suffer from poor design which means the fan has to build a little pressure per say to force the air down them. Hence if there is a leak in the divider it will take the path of least resistance back into the return side. This does make sense. What do y'all think?
He told me he wouldn't rule out a leak, because they've had them before. He would check the temperature of the cold air coming out of it. It could be a combination of a leak in the divider, and low freon, because it was taking longer than normal to cool down. He had a A/C guy once that had a camper install Schrader valve's on his unit to charge it. He said the unit didn't seem to last much longer. The one problem is that the manufacturer won't tell them any specs or exactly how much freon to put in them. It's a shame, but welcome to today's throw away society...🤷

[KRedburn]

I had same problem with my 2018 motorhome. Has Atwood a/c units. The divider was not properly installed in both units. Put divider in proper place and used furnace tape to seal. A/C is great now.

[AndyK]

Originally Posted by KRedburn

I had same problem with my 2018 motorhome. Has Atwood a/c units. The divider was not properly installed in both units. Put divider in proper place and used furnace tape to seal. A/C is great now.

Well maybe it's a simple fix. We have a Dometic A/C unit. I did ask about the cost to add the second unit later on since it was a option

[Witch Doctor]

Originally Posted by AndyK

Update.....

I dropped the trailer off today, and talked to the tech. The one thing he said he needed to check was to see if the cold air was leaking through the divider into the return side. He said this would cause it to freeze up, and low volume out of the ducts. I asked about a obstruction in the ducts. He said that he would check, but most of the time that's not the case with a newer RV. The RV ducts suffer from poor design which means the fan has to build a little pressure per say to force the air down them. Hence if there is a leak in the divider it will take the path of least resistance back into the return side. This does make sense. What do y'all think?
He told me he wouldn't rule out a leak, because they've had them before. He would check the temperature of the cold air coming out of it. It could be a combination of a leak in the divider, and low freon, because it was taking longer than normal to cool down. He had a A/C guy once that had a camper install Schrader valve's on his unit to charge it. He said the unit didn't seem to last much longer. The one problem is that the manufacturer won't tell them any specs or exactly how much freon to put in them. It's a shame, but welcome to today's throw away society...🤷

I doubt if it's a short cycle return air problem, your units 3 years old, there should have been a spec plate that gives amps , voltage and oz Of Freon and type, even a car ac has that, what brand is it? Nothing else you can do but let them check.

[AndyK]

Originally Posted by Witch Doctor

I doubt if it's a short cycle return air problem, your units 3 years old, there should have been a spec plate that gives amps , voltage and oz Of Freon and type, even a car ac has that, what brand is it? Nothing else you can do but let them check.

It's a Dometic unit. I don't know what model. They installed either 13,500, or 15,000 btu units on them with a second unit as a option. I assume it's a 15,000, but I don't know. They said they would find out, and let me know definitely.

[Super Flag]

Even with the possibility of cold air by-passing, the compressor should shut down and thus preventing the icing of the evaporator coil. Yes, some finessing of the air leaks in the duct work is somewhat normal, but this is not the root cause of the unit icing up.

If the unit is low on refrigerant due to a leak, adding a service valve in order to add a few ounces for refrigerant has not eliminated the leak. The only way to solve your problem if it is a leak is to replace the top unit (condensing unit). Chances of finding the leak, making repair and recharging is a shot in the dark. These units are evacuated and charged with the proper amount of refrigerant and then seal. A service tech at a RV dealership would not have the proper equipment/tool to perform the service needed as noted, speaking from experience as a A/C service tech.

[AndyK]

Originally Posted by Super Flag

Even with the possibility of cold air by-passing, the compressor should shut down and thus preventing the icing of the evaporator coil. Yes, some finessing of the air leaks in the duct work is somewhat normal, but this is not the root cause of the unit icing up.

If the unit is low on refrigerant due to a leak, adding a service valve in order to add a few ounces for refrigerant has not eliminated the leak. The only way to solve your problem if it is a leak is to replace the top unit (condensing unit). Chances of finding the leak, making repair and recharging is a shot in the dark. These units are evacuated and charged with the proper amount of refrigerant and then seal. A service tech at a RV dealership would not have the proper equipment/tool to perform the service needed as noted, speaking from experience as a A/C service tech.

The sensor in the evaporator core is working. It does shut the compessor off after it ices up. If in auto it shuts the fan off too. Then after a short time it will turn back on, and usually blow what's left of the ice off into the vent.

[KFX450RXC]

Originally Posted by str8t six

if its freezing up with the fan on all the time, then it is probably leaking refrigerant and thats why its freezing up.

Mine did the exact same thing on my Work & Play. It sometimes spit out chunks of ice big enough to put in my Coke Zero.

It was a small coolant leak. The AC unit was replaced. No problems after that.

[reddiver]

In my experience when the A/C freezes up it is most likely low or no refrigerant. check that if you can. I have never found schader valves on these small A/Cs so checking is difficult.

[Super Flag]

Based on the fact that the sensor is shutting down the condensing unit, the unit is most likely low on refrigerant. Most hermetically sealed units that behave in this fashion have a system leak and low on refrigerant charge. I could be wrong, been wrong before. Keep us posted on the outcome of the final solution. My desire is to provide you with enough ammunition to deal with the service department techs so that your A/C problem is totally eliminated.

[AndyK]

Originally Posted by Super Flag

Based on the fact that the sensor is shutting down the condensing unit, the unit is most likely low on refrigerant. Most hermetically sealed units that behave in this fashion have a system leak and low on refrigerant charge. I could be wrong, been wrong before. Keep us posted on the outcome of the final solution. My desire is to provide you with enough ammunition to deal with the service department techs so that your A/C problem is totally eliminated.

Thank You. I appreciate that. That is the good thing about these groups. It keeps us all better informed.