duo therm ac?

mikf · 07-20-2015, 08:43 PM

I am trying to help a friend with his roof mounted duo therm 15000 btu ac. it quit cooling. when it worked ok you could hear the compressor kick very distinctly about 2 minutes after it called for cool. now about 2 minutes after you turn it on you have to listen closely, but it does kick on, but does not put out cool air and the compressor gets very hot. we figure it has lost its freon charge, but was looking for any other suggestions. it is a 2003 so we are thinking a new unit would be a good idea if that is the problem. I think we can have one in a week and the dealers are booked until the end of august and he does not want to loose the rest of the season so we are trying to fix it or buy a new one. and yes I know it is hot outside, but the air coming out of the vents does not even start to feel cool, so we are confident there is a problem.

jacwjames · 07-20-2015, 08:52 PM

Is this a heat pump type unit. If you are sure the compressor is kicking on it could be the reversing valve that is not working. This is a solenoid type valve. When the compressor starts it defaults to a heat pump and the reversing valve kicks in and turns to cooling.

I had a similar problem and found that a wire had rubbed and gone to ground not letting the valve reverse. Fixed the short and tied wire to where it wouldn't rub anymore, ~4 years later it's still working.

Also, check to make sure the compressor is starting, it could need a capacitor, they sell hard start capacitors.

Here is a place to look for parts, need model and SN
https://www.edometic.com/allusr/sp.nsf/spcac?ReadForm

jfran304 · 07-20-2015, 08:53 PM

PPL Motor Homes is having a sale on some of their AC units. I haven't replaced one myself but they say the hardest part is getting the new one on top of the coach.

I'm sure if you check you tube you will be able to find instructions on how to replace/install one.

https://www.pplmotorhomes.com/parts/...er-parts-1.htm

Jon

Old Scout · 07-20-2015, 08:58 PM

Not much of an expert on AC but unlike some roof top ACs [eg Coleman], Duo Therms are pretty good until they quit. Things like mother boards and capacitors can be replaced but almost no one will mess with refilling freon on these units. If the unit is OEM 2003, you got a pretty good run out of it--go buy a new one and dont look back!

Having said this--the main challenge with replacement is if you have two or more units, one is slaved to the other. New units have a different control system from your 03 so you have to order a "modified" mother board so your new unit can talk to your old unit. PPL was very good about helping me figure out what board was needed for the new unit.

Mr_D · 07-20-2015, 09:08 PM

Our OEM '02 13.5 Penguin heat pumps were still working just fine when we traded the DSDP in.

Thunderfoot · 07-20-2015, 09:27 PM

mikf, the reason I repaired my original Duo-Therm AC's when they failed was two fold... 1) parts were cheap and diagnostic help was readily available and 2) as Old Scout says, it's no picnic and costs some $$$ to upgrade the new generation AC's to the older coaches.

If the system has lost Freon you should be able to see an oily residue somewhere on the unit. If that's the case, it's probably time for a new one. As posted above, start/run capacitors, reversing valves, & chaffed/broken wires are a common cause of AC issues and an easy fix. Good luck with the repair

mikf · 07-21-2015, 06:35 AM

thanks for the replies, not seeing a oily residue any place is one of the reasons, I am hesitant to replace unit at this time. I am sure the compressor is coming on as I have been on the roof with cover off to hear it. and I was watching for the voltage when it came on. Like I said in the first post it does not make that loud noise when it comes on. and the compressor gets very hot when it runs for a few minutes.

Thunderfoot · 07-21-2015, 10:45 AM

For trouble shooting questions with a live person try the link below. Mr Hendrix has helped numerous members here, is a retired Duo Therm tech, and has many parts in stock, even for the older units. He is one of my most valued resources and great to deal with. You will find his cell number listed on his web page listed below. Good luck!

william hendrix - Home

shiggs68 · 07-21-2015, 03:01 PM

Quote:

Originally Posted by mikf

I am trying to help a friend with his roof mounted duo therm 15000 btu ac. it quit cooling. when it worked ok you could hear the compressor kick very distinctly about 2 minutes after it called for cool. now about 2 minutes after you turn it on you have to listen closely, but it does kick on, but does not put out cool air and the compressor gets very hot. we figure it has lost its freon charge, but was looking for any other suggestions. it is a 2003 so we are thinking a new unit would be a good idea if that is the problem. I think we can have one in a week and the dealers are booked until the end of august and he does not want to loose the rest of the season so we are trying to fix it or buy a new one. and yes I know it is hot outside, but the air coming out of the vents does not even start to feel cool, so we are confident there is a problem.

You really need to check with a clamp-on amp meter the current draw of the compressor. Getting hot is a symptom of a bad starting capacitor.

Here is a general service manual. Page 28 tells how to check the starting capacitor.
http://bryantrv.com/docs2/docs/acservice.pdf

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