Ordering my new 5th wheel. Dealer recommended 3 a/c on a 39 ft model. They said in 2012 government made them use different freon and it doesn't cool like the older ones, according to Dometic. Anyone hear of problems with them?

We have a Flagstaff Classic model number 831 about 34 feet and our 15000 BTU in Billings, Mt last summer couldn't keep up and I doubt anything could have. JMHO

The newer units are using R410a, which has been out for several years. I believe Dometic started using it in their marine units around 2007 or so. There were grumblings about it not cooling as well as R22, but the main difference is in the amount of gas used in the charges, usually in oz. The average use is not going to know the difference. Charging with it is a lot harder than with R-22 because of the extremely high pressures it runs at and it has to be charged either by weight or by super heat because ambient temperature really affects the high side pressures and a few degrees change can send the high side pressures all over the map.I've heard that a replacement is coming for it, but I don't have any specifics, so it looks like we will be living with this one for a while. You can't just charge it and get it close with gauges like you could R-22. It's like when R-134a replaced R-12 in refrigeration. Nobody really noticed a big difference. I haven't noticed a difference in discharge air temps between the two. If you replace the AC in a stick & brick you are going to get a unit charged with R410a, trade name, Puron.

I think the campers just keep getting bigger We got our 08 new and the salesman said the 15,000 btu AC would be enough to keep it cool. Well it works 90% of the time but that 10% you need the extra cooling you REALLY NEED IT! I wish we would have put the 13,000BTU one in the bedroom:{ live and learn or add one or suffer through the heat. The saving grace is we are at the lake in the water on those hot days instead of sitting in the camper.

I was on another forum a couple of weeks ago and a similar subject came up. A couple were looking at a pre 2012 (not sure of the exact year) fifth wheel and on the same lot with a "new" fifth wheel. It was hot out and they noticed the used trailer was freezing inside, the 2014 unit wasn't quite keeping up with the heat. The sales person explained that "the newer air conditioning units don't do as good of a job as the older units". Made me wonder, we only have one air conditioner and here in Wi for the most part it does OK but what about down south? HmmmmMaybe somebody with real life experience can enlighten us.Dan

I can hang meat in our 40' fiver with both the 15000 and 13500 BTU A/C's running in the Alabama sun in August. Usually only run the 15000 during the day and at night turn on the bedroom A/C on low.

Did they change refridgerant type in newer A/C's ?

20 Replies

Huntindog
Explorer
May 14, 2014
woodman1 wrote:
All I'm saying is what the dealer told me. That Dometic said with the newer freon, it doesn't cool as well. Just saying.

Here is the deal.
The newer refrigerents have a higher boiling point. A pot of water boils at 212. No matter how much more heat you apply to it, 212 is the max. The extra heat is carried off as steam or gas.
R22, R410,R12, and R134 work the same way. Except the boiling points in all of them are below freezing. In a refrigerant system the Freon is boiled off at a controlled rate, absorbing heat from the air as it does so. The compressor then compresses the Freon gas into a liquid that is hotter than the ouside temperture so that it can be cooled by it, and then the process repeats.

So any of the Freons are perfectly capable of maintaining a comfortable temp. The hardware components need to be sized correctly/differently due to the different boiling points, but since they are ALL below freezing, they will all work equally. In fact, the ACs are designed not to allow the outlet air temps to get to the freezing point, to avoid icing up, and restricting the airflow.

And yes some new Freons are coming. It seems that they have just discovered that 410 and 134 are bad for the environment....
I say follow the money.
Dupont held the patent on R12. When it ran out everyone was making it and the price dropped to .79 a can. Dupont lobbied congress about the problems with R12, and got it outlawed. The new 134 had a brand name of Suva and was said to be problem free. Guess who held that patent? Dupont.
I never looked at the 22 vs 410 situation, but I bet it is very similar
mark1228
Explorer
May 14, 2014
dougrainer wrote:
woodman1 wrote:
All I'm saying is what the dealer told me. That Dometic said with the newer freon, it doesn't cool as well. Just saying.

This gives YOU a heads up that the "dealer" will say anything. So, how can you trust him in the future? Clarify, did a TECH state this or a "Salesman". BIG difference in where it comes from. Doug
..

Another factor to consider in cooling the newer units would be if it is going to have a white exterior or something darker like many of the new RV's have. With a darker exterior, you may need more btu's to keep it cool.
TechWriter
Explorer
May 14, 2014
TXiceman wrote:
I love to hear the stupid stories that RV dealers come up with.

Yeah, I think you could fill a book.
C_Schomer
Explorer
May 14, 2014
I just cleaned and combed the coils in our 08 Dometic and it's R22. We're changing our obsolete low pressure chillers at work to 134a screws. I hope the gov't doesn't phase it out now. Craig
dougrainer
Nomad
May 14, 2014
woodman1 wrote:
All I'm saying is what the dealer told me. That Dometic said with the newer freon, it doesn't cool as well. Just saying.

This gives YOU a heads up that the "dealer" will say anything. So, how can you trust him in the future? Clarify, did a TECH state this or a "Salesman". BIG difference in where it comes from. Doug
MrWizard
Moderator
May 14, 2014
woodman1 wrote:
Ordering my new 5th wheel. Dealer recommended 3 a/c on a 39 ft model. They said in 2012 government made them use different freon and it doesn't cool like the older ones, according to Dometic. Anyone hear of problems with them?

The normal Two might do it, but having the 3rd will be good insurance
There are time our 34 ft must have both A/C's on, and is still not quite as cool as we would like, other times one is enough even at 90+

Direction parked, aka broadside to the Sun, shade, hot winds etc..
Play a big part
Many people have a hard time cooling the RV with slides out
The 3rd a/C is a good idea
hypoxia
Explorer
May 14, 2014
Vehicles will be changing from R134 to R1234 soon also. I'm sure we'll hear the same stories with it.
woodman1
Explorer
May 14, 2014
All I'm saying is what the dealer told me. That Dometic said with the newer freon, it doesn't cool as well. Just saying.
Bob_Landry
Explorer
May 14, 2014
I agree that a BTU rating is what it is. Even if there were some slight difference, the casual owner would not know because he has nothing to measure it with. It gets down to engineering which is beyond the scope of most of us and certainly beyond the casual user.The big difference is the pressures they run at. My R22 units kick off on high head pressure at 425lbs while the R410a units kick out at 575lbs. The suction side runs at almost twice what the R22 units run at and all of that takes some getting used to.

Dometic started building their marine systems with R410a back around 2007, but we are just now starting to see problems with them, probably because of the age of the equipment. That's going to be the norm with any generation of equipment. And that is just a generalization. I have 20-25 year old R22 equipment out there that still have the factory seals on the service ports.
TXiceman
Explorer II
May 14, 2014
I love to hear the stupid stories that RV dealers come up with. The newer units have R410a as a refrigerant rather than the R22 which was phased out for all new production units. There is no difference in cooling between an older R22 unit and a newer R410A unit. Both produce the same 15,000BTUH.

Now where there was some capacity reduction or poor cooling was in converting an R22 unit over to a new refrigerant blend. New units are designed to operate on the new refrigerants.

Ken