Community Forums

Dutch Star Don · 04-17-2011, 03:04 PM

I can fix many things, but I know absolutely nothing about A/C units. We went away for the weekend and hit some 95 degree weather on Saturday while boondocking. I fired up the generator and then both DuoTherm A/C units. The front came on and worked fine. The rear blew hot (really hot). I cycled it through a couple of times and had the same outcome. Sunday morning, while everything was cool, I started the generator and tried just the rear air. It started and blew cold. We drove home, I parked the coach and plugged into my 20 amp service. I tried the A/C and it blew hot air. Just to double check, I started the generator and tried again, nothing but hot air.

The fans are running and I'm showing that I'm drawing about 15 amps when the unit kicks on. I'm guessing the compressor is running???

I went on the roof and bypassed the "Klickson", (SP) switch that is located in a can at the back of the compressor and still the same problem.

I then located the "run capacitor" and the "start capacitor" on the side of the unit. DuoTherm had used a piece of metal plumbers tape to secure the two capacitors to the housing and the "run capacitor" was moderately distorted.

Okay......that's the extent of what I know and did. I've attached a photo of both parts below. Has there been a common problem where either of these have gone bad or would do what I've described above. I did a search and dib't see my iexact issue.

DuoTherm Model #630035.321

Thanks for any help.

bullydogs1 · 04-17-2011, 03:35 PM

Don...

Do you have heat pumps?...You could have a sticking valve in the rear air that is making it perform in heat pump mode (believe it or not, that's the default) and you need voltage and the brain to switch it. If you have generator on, try it again and see if you get cold air, then throw the front one on. If the rear one then fails it could be the control unit in the rear that gets the voltage to make it go back to AC mode.

Hope this helps...

wa8yxm · 04-17-2011, 08:10 PM

While you were on the roof, Did you clean whatever could be cleaned?

Bill2 · 04-18-2011, 08:02 AM

Don, did you smell anything burning when this happened? If so then it is the start compacitor. If not then it is the valve that switches over from heat pump to a/c. I don't know where it is located. I just had a unit replaced in Yuma because of the very same thing. The start compacitor went out and then burned up the compressor.
Bill

I went

Quote:

Originally Posted by Diplomat Don

I can fix many things, but I know absolutely nothing about A/C units. We went away for the weekend and hit some 95 degree weather on Saturday while boondocking. I fired up the generator and then both DuoTherm A/C units. The front came on and worked fine. The rear blew hot (really hot). I cycled it through a couple of times and had the same outcome. Sunday morning, while everything was cool, I started the generator and tried just the rear air. It started and blew cold. We drove home, I parked the coach and plugged into my 20 amp service. I tried the A/C and it blew hot air. Just to double check, I started the generator and tried again, nothing but hot air.

The fans are running and I'm showing that I'm drawing about 15 amps when the unit kicks on. I'm guessing the compressor is running???

on the roof and bypassed the "Klickson", (SP) switch that is located in a can at the back of the compressor and still the same problem.

I then located the "run capacitor" and the "start capacitor" on the side of the unit. DuoTherm had used a piece of metal plumbers tape to secure the two capacitors to the housing and the "run capacitor" was moderately distorted.

Okay......that's the extent of what I know and did. I've attached a photo of both parts below. Has there been a common problem where either of these have gone bad or would do what I've described above. I did a search and dib't see my iexact issue.

DuoTherm Model #630035.321

Thanks for any help.

chiefdave · 04-18-2011, 04:46 PM

Don, Had to replace two start capacitors on my rig over the last two years. Each one was completely burnt. Your picture does not indicate any burn marks so I would suspect that maybe the valve is sticking if you are sure the compressor is running. Another suggestion would be to swap out the run and start capacitors on units to confirm their performance. Additionally, the new Hard Start Kit, 3311883.000, includes the Start Capacitor plus the PTCR relay. I purchased an extra kit if you can't locate one. Just let me know. Good Luck

FLYING BUTCH · 04-19-2011, 06:38 AM

my middle ac blew hot air, it was some selenoid, dealer replaced for less than $100

itdave · 04-19-2011, 08:09 AM

Don
This sound like a reversing valve problem. The reversing valve requires 120 volts to go into cooling mode. The power for the valve comes from a tap off of one of the capacitors. On mine I found there was a particle short to ground so the reversing valve was only seeing 75 volts not enough to stay in cooling mode. I would replace both capacitors clean up any rust or arcing traces then reconnect everything. Use a meter to check the voltage at the reversing valve when switching between cooling and heat pump modes. BTW you can find replacement capacitors at any good electric motor repair shop. Price is much cheaper than buying from a Dometic or an RV shop.

Dutch Star Don · 05-04-2011, 09:57 AM

Just wanted to update everyone......After everyone's advice, it seems that my problem was most likely the reversing valve. We left for a trip to the Grand Canyon and I knew I wouldn't need the A/C so I held off doing anything else, other than removing all of the wires on the start capacitor, run capacitor and reversing solenoid and making sure everything was clean.

While at the Grand Canyon I used the heat pump side of the bad unit for several days (exercised it) since the heat worked fine. When I returned home the weather was hot so I turned the rear A/C on to see what would happen. It ran fine for over a half hour when I finally turned it off. I'm guessing a sticky reversing valve as you guys said. I rarely run that rear unit and is probably part of my problem.

My neighbor is an A/C guy so I'm going to see if he can get me the run capacitor, start capacitor and the reversing solenoid at a good price. I'll keep the two capaciotrs as spares and replace the reversing solenoid. If not, PPL has all three parts on line for about $60.00.

Thanks for everyone's help. Immediately after dropping $2100.00 for the sway bars, the A/C looked like it was going to need replacing and then I saw some things on the rear tires I didn't like. When it rains, it pours. Tires are at ridiculous prices right now!

Mike Canter · 05-04-2011, 10:24 AM

Don, if you need tires take a look at the thread I just started on the Monaco International RV Club Fleet Buy.

Dutch Star Don · 05-04-2011, 03:58 PM

Mike...You posted about a day late. I went back to what I did before. My buddy owns a tire store so he's ordering the tires for my to pick up from the distributor. He charges me $25.00 each for doing the ordering. These guys around here are even expensive for mounting and balancing. I'll pull the wheels myself and have a local shop mount them. I ordered Centramatics today for the rears.

jeepsrule · 05-05-2011, 06:17 AM

Let me piggyback on here with an AC question now that Don has all the AC experts warmed up.
My rear unit seems to cycle off very fast at times. I notice this in AC mode when I have them set and the temps outside drop close to the temp set on the thermostat. Lets say the AC is set at 76* and during the night the temps get down close to that. My AC will kick on and then turn off after about a minute. Not enough time to cool anything, then It will wait a while and do it all over. Only the rear unit does this and the unit seems to work fine when it's hotter out or if you turn the settings down lower. Any thoughts are appreciated???

I'm going up and pull the covers off and clean the units up this week, anything I should look for??

gregk · 05-05-2011, 06:51 AM

Thought I would offer my heat pump experience. On the 99 Endeouver I had I always used the furnace and never the heat pump. The heat pump got turned on by mistake after 6 years of ownership and of course would not return to a/c. Had to replace the unit.

The moral is exercise the unit on heat pump regularly.

Mike Canter · 05-05-2011, 06:53 AM

Jeepsrule...that problem of short cycling can occur if a vent is aimed right at the thermostat temp sensor. Do you have those little remote temp sensors or is yours located in the thermostst?

jeepsrule · 05-05-2011, 07:36 AM

Quote:

Originally Posted by Mike Canter

Jeepsrule...that problem of short cycling can occur if a vent is aimed right at the thermostat temp sensor. Do you have those little remote temp sensors or is yours located in the thermostst?

Mike I have the remote units and it's on the back wall by the electric panel and closet. Where the vents are pointed doesn't seem to matter, but generally are pointed at my DW not the sensor