Community Forums

Biggestleo45 · 04-17-2022, 11:05 AM

My new to me rig has given me a surprise. The center and forward ac systems are not working. It appears to be lack of refrigerant. Sounds like it time for new ones. Just replaced the rear before we purchased it. So, there appears to be a back order situation for Dometic 15k btu units with heat pump. Has anyone replaced the 15k with 13.5 k and were the results acceptable? I have had several Monacos with 3 - 15k units and cannot recall ever needing all three to stay comfortable. We've lived a charmed life. In 27 years of RVing in motorhomes we have never replaced an AC unit.

ThunderRidge · 04-17-2022, 03:00 PM

Please post your year, make, and model in your signature line. It will help others help you.

Biggestleo45 · 04-17-2022, 05:24 PM

2008 Mountain Aire 4523.

craigd853 · 04-17-2022, 06:49 PM

Quote:

Originally Posted by Biggestleo45

My new to me rig has given me a surprise. The center and forward ac systems are not working. It appears to be lack of refrigerant. Sounds like it time for new ones. Just replaced the rear before we purchased it. So, there appears to be a back order situation for Dometic 15k btu units with heat pump. Has anyone replaced the 15k with 13.5 k and were the results acceptable? I have had several Monacos with 3 - 15k units and cannot recall ever needing all three to stay comfortable. We've lived a charmed life. In 27 years of RVing in motorhomes we have never replaced an AC unit.

Hello sir, another suggestion is to buy service taps for both a/c's and add a little freon to get the a/c's to temporarily work until you can get the units you want. Service ports are cheap and connect to your low side thru a piercing valve inside the service port thereby allowing you to add freon to your system. This should last you a while as long as the leaks are not severe. Any home a/c store like RE MIchaels for instance and they should have these and you only need to know what size the suction side of your a/c unit is so they can give you the right size. IE 1/8,1/4, 3/8 inch. Good luck

jacwjames · 04-17-2022, 07:05 PM

Old & new units don't work well together. It they installed a new unit using the old thermostat they probably used a different control board to make it work.

If you install two other new units you'll have to work out what needs to be done.

You might consider moving the 15K unit up front where a bulk of the cooling is required and put a smaller one in the bedroom and the other up front.

When I had questions I called and talked to someone at PPL where I bought my new units. I replaced both my 13.5 units with 15K units. In really hot weather the two smaller ones couldn't keep up, maybe due to age. Instead of buying a 10 button CCC I decided to go with an Easy Touch thermostat. Nice features, beside being bluetooth or internet capable inwhich you can start stop each unit you can check temps and it will send alerts if you have internet connected.

Biggestleo45 · 04-17-2022, 08:03 PM

Thanks for the input. I hadn't considered a temporary recharge. A great thought.

The new rear ac is the newest model and the control board was replaced to dumb it down to work with the old t-stat. I will swap out for the newest ccc2 when the replacements are done.

Fefanatic · 04-17-2022, 10:31 PM

Quote:

Originally Posted by jacwjames

Old & new units don't work well together. It they installed a new unit using the old thermostat they probably used a different control board to make it work.

If you install two other new units you'll have to work out what needs to be done.

You might consider moving the 15K unit up front where a bulk of the cooling is required and put a smaller one in the bedroom and the other up front.

When I had questions I called and talked to someone at PPL where I bought my new units. I replaced both my 13.5 units with 15K units. In really hot weather the two smaller ones couldn't keep up, maybe due to age. Instead of buying a 10 button CCC I decided to go with an Easy Touch thermostat. Nice features, beside being bluetooth or internet capable inwhich you can start stop each unit you can check temps and it will send alerts if you have internet connected.

Last summer I replace one of my Dometic units and the new unit is backward compatible. OP most likely has 5 button thermostat and all those control boards are still the same, even in the new units.

Fefanatic · 04-17-2022, 10:34 PM

Quote:

Originally Posted by Biggestleo45

Thanks for the input. I hadn't considered a temporary recharge. A great thought.

The new rear ac is the newest model and the control board was replaced to dumb it down to work with the old t-stat. I will swap out for the newest ccc2 when the replacements are done.

Are you going to have a ac tech look at them? Reason I ask is most of the time it's not a freon issue but possibly a starting/run capacitor issue. I find it odd that two units would run out of refrigerant in the same time period.

TXiceman · 04-18-2022, 12:29 PM

9 times out of 10 the issue is not low on refrigerant...lack of cooling is typically low or reduced air flow. Have you checked the temperature across the unit? Using a thermometer (not an infrared temp gun), run the units on high fan for about 10 minutes. Take a temperature reading at the inlet to the unit and then one at the closest air outlet. The outlet should be 20 degF lower at the outlet.

Have you done any trouble shooting? is the fan running, what amperage is the unit drawing, does the compressor try to start?

The saddle clamp valves are just a temperature fix and will eventually leak.

Ken

Biggestleo45 · 04-19-2022, 05:49 AM

I did the normal diagnostics. The compressors both run and the units each draw 12.2 amps. Only very slight cooling entering the evaporator cabinet on one and none on the other.
I will try adding refrigerant and cross my fingers. Currently the Penguin hi capacity units are back ordered and I would like to wait until they are available.

MrMark52 · 04-19-2022, 05:56 AM

Quote:

Originally Posted by Biggestleo45

I did the normal diagnostics. The compressors both run and the units each draw 12.2 amps. Only very slight cooling entering the evaporator cabinet on one and none on the other.
I will try adding refrigerant and cross my fingers. Currently the Penguin hi capacity units are back ordered and I would like to wait until they are available.

DO NOT JUST ADD REFRIGERANT! And in fact, you cannot just add refrigerant without adding a port or tap to the system.

If done incorrectly, it will leak again - as well as the original leak will still be leaking.

These units are “factory sealed” systems and there is a procedure for servicing the refrigerant side of the system - and that includes locating and fixing any leaks that may have developed.

If you want a lesson in how to follow the process of properly repairing the unit, I will be glad to describe to you. But DO NOT “just add refrigerant” to get it going.

Suburbazine · 04-20-2022, 03:13 PM

I don't know how your coach is set up exactly, but I just put a 15k RecPro (Houghton) heat pump on my cargo trailer and it outperforms my 15K Dometics by a huge margin. Both in better cooling and heating... and MUCH lower amp draw at running and startup. Granted, they don't have furnace controls so if your units control the furnace you'd have to find a workaround.

Dometic is certainly behind the times when it comes to AC.

craigd853 · 04-20-2022, 04:41 PM

Quote:

Originally Posted by Biggestleo45

I did the normal diagnostics. The compressors both run and the units each draw 12.2 amps. Only very slight cooling entering the evaporator cabinet on one and none on the other.
I will try adding refrigerant and cross my fingers. Currently the Penguin hi capacity units are back ordered and I would like to wait until they are available.

I do believe adding the service valves to your low side will fix the issue, one other thing to check before doing this is to remove the duct filter and make sure your evaporator is not covered in dirt. An extremely dirty evaporator will cause cooling issues as well. Good luck sir