A/C not cooling, but seems compressor is on?

DirtyMax88

Well-known member
Good morning everyone,
I was reading through prior posts and couldn't find my exact problem, so I thought i would reach out. We have the 15k dometic whisper quiet system. Living room a/c works as it should. Bedroom a/c seems to be having issues. We have the power management system with display so you are able to see when just the fan is on, when the compressor kicks on, and when it's running. Anywhere from 11-13 amp draw while the a/c compressor is running is pretty normal I believe. Well, went out to the trailer last night to put things in for our trip this up and coming week and the bedroom ac was running, compressor was running but it didnt seem to be blowing cold air. I only had it set on 78 (and it was about 90 hear yesterday) but it wasn't cold air. Thus far, after 4 years we haven't had any problems with our units. It seems like the compressor is running (per the display on out PMS), so what should I start with to troubleshoot? Or are we part of that bad run of a/c that I have seen so much about.Thanks in advance!
 

Lynn1130

Well-known member
I am not familiar with the system you are using and someone may help there but my first guess would be that the unit has frozen up with the high heat and humidity. I have had that happen also and it means shutting the unit down and allowing it to defrost. If you have the ability to run only the fan on that unit I would do that without the compressor running. That will help move air and speed up the defrost. I would think that if it were something with the system, regulating power, that the compressor would not be running on both at the same time.
 

DirtyMax88

Well-known member
Have you cleaned the return filters?
I haven't checked them this year, we usually do that once a year, kind of an end of the season type deal, with a few other routine maintenance items. I will check the filters when i get home (had to run to the office for a bit). Thank you!

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I am not familiar with the system you are using and someone may help there but my first guess would be that the unit has frozen up with the high heat and humidity. I have had that happen also and it means shutting the unit down and allowing it to defrost. If you have the ability to run only the fan on that unit I would do that without the compressor running. That will help move air and speed up the defrost. I would think that if it were something with the system, regulating power, that the compressor would not be running on both at the same time.
This was what I thought as well. I did shut it down last night, in hopes that this may be the issue. As another person mentioned, I will check the filters when i get home and fired it back up, see how it does. Another person on the owners FB page mentioned low on Freon? Can it lose Freon, similar to a vehicles a/c system? Thanks...
 

Lynn1130

Well-known member
Can it lose Freon, similar to a vehicles a/c system? Thanks..
.

I am sure they can if there is some sort of a leak but from what some here who are much better at AC than me have said, that is not fixable. There is no way to add or replace freon.
 

DirtyMax88

Well-known member
As an update. I turned the a/c back on after sitting overnight (if it had frozen up i figured overnight would allow to thaw). I turned it back on here and its still blowing warm air. The EMS shows a 12 amp draw, so I'm assuming the compressor is on. I also checked the filters and they are pretty clean. I need to get up on the roof and pull the cover to make sure the fins and fan is clear of everything. Assuming that they are, what else should i look for?

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Doesn't your system have a freeze sensor? If so is it clipped on to the evaporator at the correct place? This sensor on Dometic AC's cuts off the compressor if it detects freezing temperatures, lets the fan blow warmer air through the evaporator until it warms up.

See Fig. 12 on page 9 of this manual: http://manuals.heartlandowners.org/...nits/Dometic/Brisk-Air-AC_installation_EN.pdf

Also, dirty evaporator fins/coils will contribute to freeze up.

I dont believe it is frozen, i turned it off to sit all night and just cranked it back up, and its still blowing warm, but seems as though the compressor is running. I can also vesually see water dripping off the roof.....

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Have you cleaned the return filters?

the return filters look good....
 

travelin2

Pennsylvania Chapter Leaders-retired
Time to replace it. Our 2yr old BR unit acted the same last May.
Mobile tech ordered and replaced on site within a week


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DirtyMax88

Well-known member
Time to replace it. Our 2yr old BR unit acted the same last May.
Mobile tech ordered and replaced on site within a week


Sent from my iPhone using Tapatalk
that's my thought. Which isnt a big deal except we dont have any mobile techs around us (in MD) and the local RV place is covered up (naturally, being summer). Not to mention we leave monday for a week long trip. Lol....great timing huh!
 

wdk450

Well-known member
If you are getting up on the roof with the AC running on full cool, you could feel the freon line going into the evaporator to see if it is cold, and look for any air obstructions. The cooling air circuit through the evaporator is probably going to be covered up.

This You Tube video on cleaning your evaporator coils might help. The AC cleaning spray can be found at home improvement stores.
https://www.youtube.com/watch?v=OCL_a_HPba0
 

travelin2

Pennsylvania Chapter Leaders-retired
that's my thought. Which isnt a big deal except we dont have any mobile techs around us (in MD) and the local RV place is covered up (naturally, being summer). Not to mention we leave monday for a week long trip. Lol....great timing huh!

Sucks!!! I went with the mobile tech from our local RV dealer (non-heartland) because they were booked 3 weeks out.
You sure the local dealer doesn’t have mobile service? Several mobile techs we’ve utilized over the years were from a local RV dealership


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DirtyMax88

Well-known member
If you are getting up on the roof with the AC running on full cool, you could feel the freon line going into the evaporator to see if it is cold, and look for any air obstructions. The cooling air circuit through the evaporator is probably going to be covered up.

This You Tube video on cleaning your evaporator coils might help. The AC cleaning spray can be found at home improvement stores.
https://www.youtube.com/watch?v=OCL_a_HPba0

Thank you, I will check that out when I'm up there. I appreciate the advice!

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Sucks!!! I went with the mobile tech from our local RV dealer (non-heartland) because they were booked 3 weeks out.
You sure the local dealer doesn’t have mobile service? Several mobile techs we’ve utilized over the years were from a local RV dealership


Sent from my iPhone using Tapatalk
I'm not sure honestly I can give them a call and find out. Thank you.
 

Chrisandsama

Well-known member
You say your getting water running off of the roof tells me there is heat transfer taking place as it should be, odd.....
 
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