Replacement AC Units

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Replacement AC Units

March 10, 2013, 06:44:15 pm

Hi all. We have a 1997 U320 in need of replacement AC units. Anyone have any thoughts on what brand/model would be a quality unit to replace our old Dou-Therms?
We don't really need any heat function and don't care if the new units work off a wall thermostat or have the ceiling controls.
Thanks for your replies!

Re: Replacement AC Units

Reply #1 – March 10, 2013, 07:47:07 pm

It appears the 97 320 came with ducted a/c units that are tied in with the same thermostat as the Aqua Hot heating system, so replacing with a ducted model would seem the better choice as replacement.

Re: Replacement AC Units

Reply #2 – March 10, 2013, 08:03:16 pm

Dave is right get the ducted unit with the wall control. I would also get the heat strips. Not that I use them alot they do a good job when I exercise the coach genny in the winter.

Re: Replacement AC Units

Reply #3 – March 10, 2013, 08:15:11 pm

Be aware that my experience with the new DuoTherms are that they are noisy as h.... Probably in ducted form they will be quieter. I have not found any way to quiet the new one in front, the old one is fine.
Gary B

Re: Replacement AC Units

Reply #4 – March 10, 2013, 09:32:38 pm

If the old units are still working I would not change them as the new dometic units are indeed very noisy even with ducted air

Re: Replacement AC Units

Reply #5 – March 10, 2013, 10:19:13 pm

Quote from: red tractor – March 10, 2013, 09:32:38 pm

If the old units are still working I would not change them as the new dometic units are indeed very noisy even with ducted air

Roger that. Big difference in noise between the two. The new ducted units are far noisier than the old non ducted.

Chuck

Re: Replacement AC Units

Reply #6 – March 10, 2013, 10:31:39 pm

We had new Dometic units installed in 2010 and are fighting the increased noise to this day (Steve has a couple of isolator kits from Dometic to try next). We have tried roof drain kits (with extra gaskets), replacing the gaskets, and Dynamat thus far without achieving the lower noise of the original units.

We noticed newer FTs have Coleman units installed (heatpump models, I believe). Obviously these require a different control unit but I wonder if they are quieter (and why FT changed brands)?

Michelle

Re: Replacement AC Units

Reply #7 – March 10, 2013, 10:37:30 pm

It'll be nice when variable speed inverter style rv units replace these dinosaurs. Why this hasn't been done yet is beyond me, guess they're still making enough money with their captive market with the old tech.

Chuck

Re: Replacement AC Units

Reply #8 – March 11, 2013, 01:09:37 am

Because of the many complaints on the new Dometic units being way too loud, I have been thinking how one can get a broken unit working again. I would much rather replace than fix, but maybe we need to learn how to fix them.

Problems are probably, roof blower motor, starting capacitors, circuit board, refrigerant gas leak and dirty coils.

Has anyone had to fix these problems and get the unit cooling again?

We don't ever use our roof air for heating as we can heat other ways, but can only cool with the roof unit. Since we don't want to put more wear then necessary, we save them for just cooling.

Re: Replacement AC Units

Reply #9 – March 11, 2013, 08:14:16 am

Barry, My front unit failed due to leakage from the condensor coil. There did not appear to be any way to repair it and I was in Wichita in the hottest summer they had had in years. ( Why don't these AC units fail in December ? ).
Gary B

Re: Replacement AC Units

Reply #10 – March 11, 2013, 09:01:27 am

Quote from: Barry & Cindy – March 11, 2013, 01:09:37 am

Because of the many complaints on the new Dometic units being way too loud, I have been thinking how one can get a broken unit working again. I would much rather replace than fix, but maybe we need to learn how to fix them.

Problems are probably, roof blower motor, starting capacitors, circuit board, refrigerant gas leak and dirty coils.

Has anyone had to fix these problems and get the unit cooling again?

As long as the condenser coils are in good shape (no signs of oil leakage, fins not corroded off excessively) these units are fixable. The #1 problem, and always the first thing to check, is a failed capacitor. The easiest way to check it is simply to insert a new cap, these are available from Grainger, Amazon, etc. The next issue will be failure of the fan motor, also a generic part available from Grainger, Johnstone, many other sources. The electronics board can be bypassed for testing of ac mechanicals, don't know if they are available but at worst you'd be looking at swapping the boards for ones compatible with a new 4 button thermostat. In this case thermostat will have to be changed out, along with boards in both units. Compressors...you're getting into the difficulty zone here, it'll take a good tech to successfully swap it out but it can be done if one is available.

Even installing a new involves a fair amount of effort and cost, it may behoove you to at least take a serious stab at repair. Of course, these things always go t.u. at the worst possible time.

Chuck

Re: Replacement AC Units

Reply #11 – March 11, 2013, 09:16:39 am

Hi Chuck,

I still have a few of the A/C boards for the Dometic four button thermostats. And those thermostats definitely are repairable.

Quote

As long as the condenser coils are in good shape (no signs of oil leakage, fins not corroded off excessively) these units are fixable. The #1 problem, and always the first thing to check, is a failed capacitor. The easiest way to check it is simply to insert a new cap, these are available from Grainger, Amazon, etc. The next issue will be failure of the fan motor, also a generic part available from Grainger, Johnstone, many other sources. The electronics board can be bypassed for testing of ac mechanicals, don't know if they are available but at worst you'd be looking at swapping the boards for ones compatible with a new 4 button thermostat. In this case thermostat will have to be changed out, along with boards in both units. Compressors...you're getting into the difficulty zone here, it'll take a good tech to successfully swap it out but it can be done if one is available.

Even installing a new involves a fair amount of effort and cost, it may behoove you to at least take a serious stab at repair. Of course, these things always go t.u. at the worst possible time.

Chuck

Chuck Pearson
1996 U295 36'

Re: Replacement AC Units

Reply #12 – March 11, 2013, 09:30:59 am

Quote from: chazb11 – March 10, 2013, 06:44:15 pm

Hi all. We have a 1997 U320 in need of replacement AC units. Anyone have any thoughts on what brand/model would be a quality unit to replace our old Dou-Therms?
We don't really need any heat function and don't care if the new units work off a wall thermostat or have the ceiling controls.
Thanks for your replies!

Here are some troubleshooting tips from Dometic to try first before thinking of replacing with louder units.
Troubleshooting Tips for Your RV Air Conditioner/ Heat Pump

Re: Replacement AC Units

Reply #13 – March 11, 2013, 11:36:28 am

We had a year plus long battle with Dometic over the noise of a new unit. They eventually sent a brand new unit which is a bit quieter but still not entirely happy. Stay away from Dometics.

Keith

Re: Replacement AC Units

Reply #14 – March 11, 2013, 04:42:15 pm

Does anyone have the specifications / part numbers for the capacitors? Are all three capacitors the same? We would like to replace them before they fail.

How would one find a replacement motor if the current motor does not have specifications?

Re: Replacement AC Units

Reply #15 – March 11, 2013, 05:02:42 pm

I matched the caps. at WW Granger they shipped all good.

Re: Replacement AC Units

Reply #16 – March 11, 2013, 08:49:28 pm

I have several 4 button boards and one 4 button thermostat. Also have several 5 button boards, but no 5 button thermostats.

Re: Replacement AC Units

Reply #17 – March 11, 2013, 08:50:45 pm

Hi Chuck,

The 4 button thermostats are repairable and currently I have some of the A/C boards for them should anybody need one.

Re: Replacement AC Units

Reply #18 – March 11, 2013, 10:37:46 pm

I replaced the fan motor in my front AC unit.
I tried to find that motor from sources other than Dometic.
Even found the company that makes it for Dometic, it's proprietary and could not buy it so gave up and went to a local Dometic supplier.
I think it was around $100. It came with new capacitors and instructions to install the new one.

Re: Replacement AC Units

Reply #19 – March 11, 2013, 11:20:09 pm

Quote from: John Duld – March 11, 2013, 10:37:46 pm

I replaced the fan motor in my front AC unit.
I tried to find that motor from sources other than Dometic.
Even found the company that makes it for Dometic, it's proprietary and could not buy it so gave up and went to a local Dometic supplier.
I think it was around $100. It came with new capacitors and instructions to install the new one.

We retrofitted a non Dometic fan motor but as I recall it was more than $100.00, AC fans tend to be expensive in general even at trade pricing. So, if it's available for 1/10 of a C-buck that's a pretty good deal.

Chuck

Re: Replacement AC Units

Reply #20 – March 12, 2013, 10:43:24 am

What does the increased noise sound like - guessing vibration (compressor or fan) or is it air flow? I think the rear Dometic heat pump unit on our coach may have been replaced as it is louder (vibration from the fan motor) than the front. Haven't gone up yet to check it out. BTW, I had Coleman heat pumps on my late model Tiffin and did not like them at all due to noise and lack of a defrost cycle which means that they cannot function well at lower temps like the Dometics can. The compressor will shut down and the unit turns on a heat strip to compensate. The Dometics put out much warmer air too.

It's a shame we don't have more choices but the supplier base for the RV industry never had much depth even when business was booming.

Re: Replacement AC Units

Reply #21 – March 12, 2013, 11:49:50 am

Jeff, The noise on my from Dometic AC is a combination of a low rumble and air flow noise. It is bad enough that you cannot watch the TV or listen to music with the front air on.
The other thing that I dislike is that there is a TWO MINUTE delay with the newer thermostats from when you turn it on til it starts to run, when it does start there is about a three second delay and then the Compressor comes on, must be a terrific amp draw at that point.

Gary B

Re: Replacement AC Units

Reply #22 – March 12, 2013, 04:48:45 pm

It's my understanding that the newer ac units with the latest iteration of "freon" require more air movement to provide cooling equal to the old units. So, lots more fan noise.

Re: Replacement AC Units

Reply #23 – August 16, 2014, 10:02:25 pm

which Dometic units are we talking about? New penguin? Brisk air? I just installed 2 new brisk air 1500 btu units with the digital boxes and thermostat. Yes they do move air, but I find it quite nice not like a lot of motels I have stayed in.

Re: Replacement AC Units

Reply #24 – August 17, 2014, 10:06:23 am

Quote from: Dave M – August 16, 2014, 09:40:34 pm

Since my heat pumps (2) are the 2001 year model using the 5 button thermostat, WHAT are the recommended replacement units for noise (noise of present units, no issues), BTU rating, compatible control wise etc. ?
Units still working fine, but maybe time to change - upgrade ?

Dave,

We haven't found any of the newer units to be quieter than the original Dometic Penguins that were on our 2003. In general the newer models are louder (although the 2014 Penguin II's seem to be quieter than the 2010 Penguins we had installed, one of which failed catastrophically after 3 1/2 years). If it were me (and granted this is limited experience), I wouldn't give up your current units until they fail to perform.

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