To replace or repair air conditioner

[stanleyz]

05 36 TK3 front a/c has bad motor, runs fine on low dies after 15 mins on high. I've done all the cheap stuff, no help. So, I can pull the motor and replace it or I can replace the A/C. BTW it is a 12.5 Dometic on the comfort control system, ducted of course. My lean is to replace the A/C then I have to decide whether to do it myself or have it done.

So has anyone ever replaced one? If so are there any snakes I need to know about? I'm thinking pull the shroud, open up the covers, remove the bolts and lift it off. Now, I'm wondering will the replacement just fit on and match up to the duct or will I get in to modifying it? All the you tube stuff I can find is for units with the panel on the bottom of the A/C (ceiling of the RV) All answers will be appreciated, knowledgeable answers will be cherished. Thanks for reading this.

[Cummins12V98]

Piece if cake to replace! I would opt for a 15k and would also get the extended warranty.

[Dapperdan]

The biggest issue for me, if I were doing it would be getting that AC on the roof. That too me spells too much risk pulling something or straining something.

Don’t they fork lift those things up there if a shop does the replacement?

Dan

[Stripit]

I have pulled mine up and off to fix a loose piece of tape that was making noise. Easy to pull off, weighs maybe 80 lbs? If I was to try to replace myself, I would have to have another person to help hoist the new and old up and down off the roof. A hi-lo would be best but using a extension ladder and ropes to use as a slide would work too. The replacement should bolt right up and fit exactly in the old opening.

[Notanlines]

I'm going to side with Cummins on this topic, although only the first half of his advice. We wouldn't buy the extended warranty. Do it yourself. Then you'll "have a story to tell.":

[wingnut60]

Stanley,
I believe somewhere I have read that the newer Dometics don't exactly PnP with the old wiring/thermostat. Might check on that with Dometic if they are reachable.
Joe

[porthole]

I replaced my 7 year old 15K with a new, much better insulted unit. Updated to the digital thermostat as well and ordered it with the heat strip again (not a heat pump). Also a new matching interior grill.

Hardest part as mentioned is getting it up on the roof.

I used ropes and pulled it up a ladder.

Old unit just took a nose dive off the roof.

[Cummins12V98]

On the unit I replaced I layed a pc of plywood over the top edges of my truck bed with truck backed tight to front of RV. Sat unit on plywood then lifted to top front of RV. I just chucked the old unit over the edge. The Dometic extended warranty from what I remember was cheap for the extra years.

[stanleyz]

Thank you one and all. So for those of you who have done this with a duct system, how is it secured to the roof. Mine looks like it has four lag bolts screwed into the plywood roof, is that correct? If so, did you just re-bolt in to the same holes? It seems to me that second bite would be a little less robust, what do you think? Thanks

[porthole]

Most have 4 very long machine screws from the bottom, inside.

[stanleyz]

Most have 4 very long machine screws from the bottom, inside.

Don’t think so with my ducted system. I have nothing on the BR ceiling but air ducts. The long bolts work with stand alone units.

[Notanlines]

Stanley, the four lag bolts are screwed into a wooden cross member. I will say that once you've taken those bolts out and ready to put a new unit in, how bad can it be? What could pull the units loose? Oh, that's right. The Comcast cable left at 12' in the RV park. Camping World replaced four of the beams, the entire roof, all the plumbing vents, no telling what else and all is good.

[stanleyz]

Stanley, the four lag bolts are screwed into a wooden cross member. I will say that once you've taken those bolts out and ready to put a new unit in, how bad can it be? What could pull the units loose? Oh, that's right. The Comcast cable left at 12' in the RV park. Camping World replaced four of the beams, the entire roof, all the plumbing vents, no telling what else and all is good.

Are you serious, that really happened to you? The cable was strong enough to destroy part of the roof? That may be the worst RV experience I've heard about except highway events. Sorry about that. I guess if they are in cross members that are solid the reinstalled lag bolts would hold. Thanks

[Chad Heiser]

Most have 4 very long machine screws from the bottom, inside.

Not on the ducted DRV AC installations. There is no acces to the bottom of the AC from inside the trailer. If it is an older non ducted installation, then removing the vent cover from inside the trailer would give you access to the screws that sandwich the AC to the roof.

[Stripit]

Mine had the 4 lag bolts and I just reused the same holes when I lifted mine up and cleaned the fan.

[porthole]

Not on the ducted DRV AC installations. There is no acces to the bottom of the AC from inside the trailer. If it is an older non ducted installation, then removing the vent cover from inside the trailer would give you access to the screws that sandwich the AC to the roof.




Was going by my old fashioned set up :D

I do have ducted AC on the main unit, but it is the style with the dump, so I can just drop the big bezel and unscrew the rooftop AC.

[Notanlines]

Keep in mind that the TV cable is supported by a 1/2 steel cable, pole to pole. RV park did have the brains enough to warn us. Pictures are worth thousands of words....

[Chad Heiser]

Keep in mind that the TV cable is supported by a 1/2 steel cable, pole to pole. RV park did have the brains enough to warn us. Pictures are worth thousands of words....

OUCH, that will put a damper on your day.

[Dapperdan]

Jim, where did that happen? I'm curious, everybody at the campground made it under the cable line but you didn't? :confused: That's really amazing.

How long did CW take to do the repair?

Sorry for highjacking this thread!:oops:

Dan

[Notanlines]

I happened at Sunny Pines RV Park in Sebring, Florida. Hurricane damage brought down the cable back in the early fall. Comcast apparently came out, repaired the TV cable but left it too low, saying they would be back to raise it to the acceptable height. The eventual end was Comcast insurance covered all repairs, Camping World in Fort Myers did the repairs in five days (let me say, their new roof installation is neater in appearance than the original) and all is well. When DW and I pulled it to get things started CW put a tech and a helper on it immediately and in 2 hours the roof was patched and we were on the road back to our spot at our regular RV park in Clewiston. They called in three weeks, we brought the RV in early Monday morning and picked it up the following Saturday morning. Oh, seventeen thousand dollars will buy a complete new roof, two 15K AC/heat exchangers and all new vents, etc. We still harbor evil thoughts towards the cable repair person, but life goes on.

[Dapperdan]

Thanks for the info Jim, I wondered how that all happened! Wow, that's a heck of a lot of damage!! I wouldn't guessed that much! :mrgreen:

Dan

[stanleyz]

Wow, that's some story to tell. Glad they got you all repaired without a court being involved.

[stanleyz]

Thought I would update this for anyone trying to deal with the same problem. Jim is correct above. the new replacement Penguin will not work with the CCC thermostat system. So I would either have to replace both air conditioners and the thermostat with the new CCC2 system. Or, replace the board in the new penguin with a modified control board to dumb down the penguin so it would work with the CCC system. Given all thatI decided to take a shot at the fan motor. I'm no wimp when it comes to working on stuff but removing and reinstalling that fan motor is a chore. Both fans are held on by clamps not set screws like the book says and they are a PITA to get off and a double PITA to put back in. Anyway, I pulled the motor and it had a couple spots where it looked a little burned and a couple black wires. I took a couple pics and sent them to my brother in law who is knowledgeable about motors. He says it is toast so I order a new one. Got it in and everything buttoned up and of course there is no change. The AC will run forever on low but only about ten mins on high. So, I'm back where I was except I'm a hundred sixty bucks poorer and have a lot of cuts on my hands and arms. The only thing left is the control board or more likely the relay on the control board. There are some trouble shooting checks I found on line for that so Ill open it up soon and run the checks. More when I know it.

[stanleyz]

OK, I'm going to post this as a close out on this thread. This will be long but if you are experiencing similar problems to mine it will be worth your time. First let me say I did not repair this unit so much as I pestered it in to submission. Here is the sequence of events.

1. Over a year ago my bed room air conditioner started running away and could only be stopped with the circuit breaker.

2. Problem was the control card in Zone 2 air conditioner so I replaced it. That corrected the problem.

3, In Feb, that unit began failing if left on Cool fan high or on cool fan auto with a temp spread of 9 degrees or more. It would run for a short time and then the fan would stop and the compressor would hum. On cool fan low or auto with a temp spread of 8 or less it would run and cool all day.

4. I replaced both capacitors but nothing changed. When I got home I removed the fan motor and found some black winding and some burnt paper. A knowledgeable electric motor guy looked and said it was toast.

5. I replaced the motor. That is a real chore. I wouldn't do it again. Anyway with the new motor the unit continued to fail on fan high cool setting but run forever on cool fan low.

6. I floundered around working on it off and on and reading a lot of forums but I had no clue. Checked amps and it was pulling like 22 amps. Too high. Checked the temp of the fan motor and it was really hot, like 170 degrees just before it stopped. That was a major clue. I then knew what was happening: motor was getting too hot and seizing or being stopped by an internal heat sensor. Now what was causing it.

7. On another forum a guy mentioned that he had the same symptoms and it took two techs 4 hours each and they couldn't figure it out. The final answer came from Dometic that some wire had to be cut but he didn't know which one,

8. I was about to remove the control board from my good unit to install in the bad unit when I pulled on the yellow wire that says medium speed on my chart. It was loose with a cap on the end. Holycrap. I went to the problem unit and dis connected the yellow wire and from then on it is running like a new one. That was it, the yellow wire was causing the fan motor to over heat on cool fan high.