Community Forums

Bertha Mae · 04-01-2023, 03:52 PM

Hello everybody,
We have two Dometic, Duo-Therm, Penguin, rooftop heat pump, air conditioner on our 04 Mountain Aire.
One of them has failed and will not cool or heat. I would like to find a used one to purchase.
Part # is 630516 (although I believe a 630515 would work).
I have read on the forum, where some owners have replaced, both air conditioners when one failed to save the trouble of having to deal with it a second time.
[Mod Edit]

Skip426 · 04-01-2023, 06:36 PM

Did the roof top unit stop all together or is the unit not producing heat when the heat pump function is selected ?

When ambient air is in the low 40s the heat pump function stops producing heated air , and you need to use the propane furnace for heat.

Isaac-1 · 04-02-2023, 04:25 AM

You are very unlikely to find a used working RV Heat pump, as few people replace them until their old unit fails. Having said that you might try one of the big RV junk yards like Colaws in Missouri or Visones in western Kentucky. It looks like Visones is likely close to your route home.

Cassy · 04-02-2023, 06:53 AM

What is not working the air conditioner or the heat?

MrMark52 · 04-02-2023, 07:07 AM

What has failed on the one you have?

95% of A/C unit failures are electrical issues in the internal wiring of the unit, a failed relay or capacitor. A new unit you would buy will come with a fresh set of the same issues that will happen again at some point.

YC1 · 04-02-2023, 07:36 AM

When I replaced mine I advertised it on Craigs list and it got snatched up almost instantly. The guy that showed up had a trailer full of them as he drove around Florida buying as many and as much of the parts as he could find. They were for a fleet he managed so was not selling.

Someone may have just changed both of theirs when one died so Craigs list might find you one.

TXiceman · 04-02-2023, 07:39 AM

I doubt if you will find a serviceable used HP/AC to put on the RV. They are mostly pulled off because they stopped working.

Has the unit been properly diagnosed as dead? If it is just a fan motor, capacitor or control, it can be fixed for fewer dollars than a new unit.

Do you really use the HP? If not, just get a standard A/C unit which will be fewer dollars.

Ken

Bertha Mae · 04-02-2023, 08:24 AM

Quote:

Originally Posted by Skip426

Did the roof top unit stop all together or is the unit not producing heat when the heat pump function is selected ?

When ambient air is in the low 40s the heat pump function stops producing heated air , and you need to use the propane furnace for heat.

With the ambient temperature outside at approximately 70°, I can set the temperature on the heat pump to 90° and the fan comes on but there is no heat produced.
Conversely, if I set the temperature on the air conditioning to 55°, the same thing happens. The fan runs but no air-conditioning.
Upon inspection, I saw that the refrigerant has been seeping out of the black Reservoir so I presume the loss of refrigerant is causing the problem.

Bertha Mae · 04-02-2023, 08:27 AM

Quote:

Originally Posted by TXiceman

I doubt if you will find a serviceable used HP/AC to put on the RV. They are mostly pulled off because they stopped working.

Has the unit been properly diagnosed as dead? If it is just a fan motor, capacitor or control, it can be fixed for fewer dollars than a new unit.

Do you really use the HP? If not, just get a standard A/C unit which will be fewer dollars.

Ken

I am 90% sure that the refrigerant has seeped out of the system and I believe they are not repairable.
Your suggestion has some merit. I will consider it.

Bertha Mae · 04-02-2023, 08:30 AM

Quote:

Originally Posted by Cassy

What is not working the air conditioner or the heat?

Neither is functioning. There is some sweating around the black Reservoir, which I believe is the refrigerant that has leaked out.
I looked at the other air conditioner on the roof and the black reservoir on. It is perfectly dry… And of course both the air conditioning function and heat pump function are working well.

YC1 · 04-02-2023, 01:22 PM

Pictures would help of course.

funjnt · 04-02-2023, 03:11 PM

Yes these units can be recharged if you find the leak. I just went through this with my rear unit. The copper line developed a pin hole leak and the refridgerant leaked out and thus stopped working. I have an ac guy who put a self piercing line fitting on the low side, pumped it up with nitrogen and found the leak. He brased the copper line where the hole was, vacumed it down and charged it up. Works fine.

The hard part is finding an old school ac tech that is willing to work on it the old fasioned way. LOL. All ac systems are serviceable with piercing fittings. Had to do the same thing to our coke machine years ago.

MrMark52 · 04-02-2023, 04:22 PM

Quote:

Originally Posted by funjnt

Yes these units can be recharged if you find the leak. I just went through this with my rear unit. The copper line developed a pin hole leak and the refridgerant leaked out and thus stopped working. I have an ac guy who put a self piercing line fitting on the low side, pumped it up with nitrogen and found the leak. He brased the copper line where the hole was, vacumed it down and charged it up. Works fine.

The hard part is finding an old school ac tech that is willing to work on it the old fasioned way. LOL. All ac systems are serviceable with piercing fittings. Had to do the same thing to our coke machine years ago.

Pierce fittings will leak!

Closed AC systems are serviced via the process port “stinger” found somewhere within the refrigerant system.
A GOOD AC serviceman will know how to properly service the unit by tapping into the process tube, following the process you mentioned for locating the leak and recharging the system - then pinch off the process tube and re-solder closed.

MrMark52 · 04-02-2023, 04:29 PM

Bertha Mae -

I believe what your calling the “black reservoir” is the compressor.

When refrigerant leaks, it leaks out as a vapor.

There can be residual oil around where the refrigerant leaked, especially if the leak was a slow one.

The operating symptoms you are describing indicate either the compressor is not running or is running and is low on charge.

There can be condensation (water) on the refrigerant piping along the very small capillary tube that feeds the evaporator if there has been a loss of refrigerant.