Air Conditioner not cooling

jimmymjr · 03-30-2019, 10:03 AM

I know, beat to death but.... My camper is 3 years old. I had the AC replaced at around 1 to 1 1/2 years under warranty, it is a Dometic. The symptoms are the same as the first time, it is not cooling enough. I live in Florida and we camp about every other month, the weather conditions are the same as last year and the year before that and so on. Normally when I turn it on it takes about 3 to 4 hours to cool down to 76 then it will cycle on and off from there. The last time I used it, I turned it on when we set up as usual, it was around 78 to 82 outside and around 95 or so inside, and overnight it dropped to the mid to upper 60’s outside. At 300 in the morning it was still hot inside to the point I was sweating, normally by 800 in the morning the windows are fogged over, so something is different than normal. The first time it was replaced the dealer said it was low on Freon, being a retired auto mechanic and seeing this type of problem in cars and trucks I agreed. They said it couldn't be charged and had to be replaced, is this true? Or could there be a possible cause I'm overlooking. The place I went to have it repaired last time sold out, I trusted them, but I don’t anything about the new owners. The large dealership in Tampa Florida I bought it from wrecked it when they had it and then had the nerve to charge me for the damage, I refused to pay it and after explaining it for about 4 hours at a volume everyone could hear, they agreed I shouldn’t have to pay. I don’t trust them to so I’m kinda on my own. The bottom line question is, should I buy a replacement unit?

**dcheatwood** · 03-30-2019, 10:12 AM

Wow. And summer is on the way!
Start with simple things. Clean filter? Even a little restriction in air flow can hinder cooling. Is it icing over? You can look up at coils with the cover off and see ice if it is. You know that's not good.
Is cool air leaking back into return air?
These are things I've dealt with thru 4 RVs.
Someone with way better info will chime in soon.
BTW, you can have connections added to you high and low pressure lines so it can be purged and recharged. Matter of feasibility. Best of luck.

A32Deuce · 03-30-2019, 10:21 AM

If its ducted, you can block off the ducts after the last ceiling vent. A lot more air flow and cooler. Did this to mine and it helped. Also awnings on side windows. Put on mine, both sides. Also helps.

Witch Doctor · 03-30-2019, 10:25 AM

There right about not being able to charge it, unless they added ports, how did they determine it was low on Freon? Only 2 ways to tell first is with gauges which they can't do. 2 nd could be what is called a delta T that is taking a read of the inside temp and the condition air temp, you should be somewhere 17 to 20 degrees different between the two, also they can measure the amps it is pulling. Other then that you have a thermister in the coil, make sure that is in the correct place. If your unit is truly low on Freon then your evap coil should be starting to freeze, that is where that thermister comes into play shutting down the compressor. I think it's to early in the year for Florida's high humidity. I would question how you could go through 2 units in a year and a half. Yes Dometic is garbage in my opinion, but not that bad.

myxkp · 03-30-2019, 10:27 AM

Quote:

Originally Posted by jimmymjr

I know, beat to death but.... My camper is 3 years old. I had the AC replaced at around 1 to 1 1/2 years under warranty, it is a Dometic. The symptoms are the same as the first time, it is not cooling enough. I live in Florida and we camp about every other month, the weather conditions are the same as last year and the year before that and so on. Normally when I turn it on it takes about 3 to 4 hours to cool down to 76 then it will cycle on and off from there. The last time I used it, I turned it on when we set up as usual, it was around 78 to 82 outside and around 95 or so inside, and overnight it dropped to the mid to upper 60’s outside. At 300 in the morning it was still hot inside to the point I was sweating, normally by 800 in the morning the windows are fogged over, so something is different than normal. The first time it was replaced the dealer said it was low on Freon, being a retired auto mechanic and seeing this type of problem in cars and trucks I agreed. They said it couldn't be charged and had to be replaced, is this true? Or could there be a possible cause I'm overlooking. The place I went to have it repaired last time sold out, I trusted them, but I don’t anything about the new owners. The large dealership in Tampa Florida I bought it from wrecked it when they had it and then had the nerve to charge me for the damage, I refused to pay it and after explaining it for about 4 hours at a volume everyone could hear, they agreed I shouldn’t have to pay. I don’t trust them to so I’m kinda on my own. The bottom line question is, should I buy a replacement unit?

Short answer, yes.
It is not normal for an a/c unit to fail so quickly. Newer units are more prone to refrigerant leaks because the tubing is thinner. Makes them cheaper to build and a marginal increase in heat transfer permits the claim of increased efficiency. I would make a very thorough inspection of the entire power supply. That was most common in my a/c repair career.

jimmymjr · 03-30-2019, 11:19 AM

Everything is good as far as clean coils and all. I haven't checked the duct work though.

jimmymjr · 03-30-2019, 11:28 AM

I've looked and its not freezing. 2 units in 3 years is to many. When they replaced it its been ice cold until this month.

jimmymjr · 03-30-2019, 11:32 AM

I'll give the power a look. I tried it at my house and at the KOA I stayed at last weekend and it did not work either place. I think the shore power is fine maybe a connection on the unit is the issue. Whatever the case I can't justify a new unit every couple of years.

tompetty69 · 03-30-2019, 01:43 PM

Not to hijack the discussion, but I have a question for Witch Doctor. Last year we were camping with two units going when the outside high temps reached 115 for a few days. Is it likely that the two units cooling the camper to say 95 would be normal? I just know it would be midnight before my sweating slowed enough that I could try to sleep. Doesn't it sound like I probably have problems as well?

Grey Wolf 26RR · 03-30-2019, 02:40 PM

My TH is 3 years old and on its 3rd Dometic AC. Both failures were due to loss of refrigerant and covered under warranty by Dometic. After the first failure I bought an extended warranty on the AC and am glad I did.

One way you can get an indicator of the problem is to measure the amps drawn while running. When mine was inoperative you could hear the compressor kick in but was only drawing about 7 amps.

My units were replaced by a local Dometic approved mobile RV service who came to my home for the repairs both times.

Witch Doctor · 03-30-2019, 03:21 PM

Quote:

Originally Posted by tompetty69

Not to hijack the discussion, but I have a question for Witch Doctor. Last year we were camping with two units going when the outside high temps reached 115 for a few days. Is it likely that the two units cooling the camper to say 95 would be normal? I just know it would be midnight before my sweating slowed enough that I could try to sleep. Doesn't it sound like I probably have problems as well?

Not really by what you stated, at a 115 degrees if you got it down to 90 you were doing good. The real problem and not to get to technical is that all the things in your RV are going to retain latent heat. Your a.c. is trying to remove that heat first. Plus all the heat stored in your ceiling and walls , rugs ,curtains and so on. That is just killer heat, in the morning if your in one place turn it on early and let it run. You will see the temp rise in the unit. Take a measurement from the supply air to the discharged air. If you are 17 to maybe 20 degrees different your unit is working. Do that early not when you inside temp gets 85 degrees. I use to make sure I'm in a CG by 3 pm ,so I didn't get the build up. Still it would take til 8 at night before I seen a drop in temp. In my 5er. Now with my M/H I just run my A.C.. as I travel with the generator on. If you have a 12v power vent run it as you travel with something open. You need to remove that hot stale air. Even if it's 90 degrees outside. I know that's not the answer you want to hear but try it....when you run your a.c. the first time take the temps and let me know...safe travels to you and yours.

Witch Doctor · 03-30-2019, 03:42 PM

Let me say also, I have seen 15 degree differential and that is pretty normal to depending on ambulant air at the unit. Another way to check is measure your air temp being brought across the coil on the roof and the discharge air on the roof you should see about 30 degree difference there. Hope all that helps. You know it's like walking into a conext box when everything has been closed up travelling in that type of heat. It's the pits I know, but I have never seen a unit built with good insulation.

MR.M · 03-30-2019, 03:53 PM

Quote:

Originally Posted by jimmymjr

I'll give the power a look. I tried it at my house and at the KOA I stayed at last weekend and it did not work either place. I think the shore power is fine maybe a connection on the unit is the issue. Whatever the case I can't justify a new unit every couple of years.

Is this the brisk air by dometic ? if so they have had more problems with the brisk aie then the other units they produce . the penguins , blizzards, and air commands seem to not have the same issues as the brisk air . if you can hear the compressor running and it's not getting cold then Freon leaked out nothing you can do. if you can tell if it running pull the cover on the roof off and touch it if it's hot as heck and not getting cold replace the unit with a different one other then the brisk air

PenJoe · 03-31-2019, 08:07 AM

Can you hear the compressor kick in? It is possible that an electronic part has failed as opposed to lost freon. Also, have you ever had a rodent problem? On our home AC, the compressor quite and we called for a repair. It was determined that mice had eaten through wires leading to the compressor and broke the circuit. I sealed the unit from further creature intrusion and the unit has been good 2 years later.

quick83 · 03-31-2019, 09:08 PM

Like many said the air coming out should be about 20 degrees colder than air going into intake. Takes about 30 minutes to do this. It’s that simple. If it’s 80 going in should be 60 coming out. If it’s 90 going in should be 70 coming out. If not you need anew Ac. Now, all that needs figured out , is why, so it does not happen again. I know running low on power will ruin them.

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