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Do I actually need 2 roof ac units?

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06-06-2018, 12:54 AM
Mike/Cindi W
Do I actually need 2 roof ac units?
have 2 of the old Duo-Therm units, one works, the other just blows air. Am considering replacing one with a Dometic Brisk II Air Conditioner (anyone have this unit? cooling only, no heat..) . Am wondering if a coach really needs a bedroom ac unit? I have read that closing off the mid-coach shutter door, keeps the front area cool enough. At night, maybe opening that door would suffice. I don't need to be frozen out at night, especially if I fix my engine compartment heat bleed over. Any thoughts..? Amazingly enough, my dash air works well and I used it most of the way thru AZ/NM heading west on my trip recently..




M/C-W

1991 early XL-style (maybe 1 of 2?) Breakaway... but prior to that actual (XL) designation...
2nd Breakaway w/Cat 3208T 250 hp motor 4 spd MT643 Allison trans Gilig Air suspension chassis/brakes
Data Tag: 9010 3694 34-BG-1B
06-06-2018, 04:22 AM
Rusty
Rather than another Dometic, I'd recommend an Atwood Air Command. Its specs are understated, it includes a heat pump, and it's quieter than the Dometic it replaced.

My only gripe (but I got used to it) is its startup and cycling, which sometimes is in stages, and the fact the blower fan runs all the time OTOH, it has 2 fans. The other gripe is the registers only go up and down, no way to divert air to the sides.

The remote is handy.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
06-06-2018, 08:47 AM
Tom and Julie
I did this and can tell you DO NOT BY THE BRISK II! They do not tell you that you must install a dedicated 12v power source from your thermostat to the ceiling unit and that the unit will not work without it. Your Duo Therm has a analog control that does not include a power feed. The only 12v close to the unit was the Fantastic Fan and it is not a dedicated source so if the fan starts it sends spikes to the AC and could damage it. The Dometic requires a separate control box ($100) that the geniuses mount in the return air inlet, effectively closing off about 40% of the return air - thus reducing the cooling capability. They address that by adding a freeze sensing tube to shut off the unit when, not if, the coils begin to ice up, because the intake is too small! I have torn down my ceiling to mount the control box remotely from the unit and fished a new 12v feed through the roof. I just cannot stand to despoil the Barth with a new wire glued, screwed or clipped to my cabinets or ceiling. It is noisy, about half as efficient as the Duo Therm and then, when you finally read the paperwork, you will see a small note that says it is for OEM installation by coach builders. Easy if you are the builder but ridiculous if trying to add later. My advice is to check on the power needs first and get one that has the proper intake sizes unobstructed. Half an air conditioner in Texas heat is a non-starter. But, so far I have not found an easy replacement other than to ditch the wall mount thermostat and use the ceiling mounted controls of the old styles. If I had this to do over I would buy a new compressor and rework the Duo Therm as needed. It will probably cost as much as the new one but I don't have to deal with their "improvements".


1993 32' Regency Wide Body, 4 speed Allison Trans, Front Entry door, Diamond Plate aluminum roof &
1981 Euro 22' w Chevy 350 engine and TH 400 tranny
06-06-2018, 09:12 AM
Steve VW
I had two Dometics on my 33 Regal that barely worked. I removed them and installed a Coleman Powersaver AC in front and a vent fan in back. It worked fine for me. I have not been in 100 degrees and sun but no problems so far.
The Coleman runs only 11 amps but it is rather noisy.
The Monarch had two Dometics that also barely worked.
I installed an Atwood in the front and I am pleased with it. I was ok with the one AC but I think I will put a second Atwood in the back for really hot days.


9708-M0037-37MM-01
"98" Monarch 37
Spartan MM, 6 spd Allison
Cummins 8.3 325+ hp
06-06-2018, 10:59 AM
MWrench
Steve You like the Atwood right? I will have to do something as my front A/C does not blow as cold as it used to and is way warmer then the bedroom A/C which is not used as much. I will probably replace both as I am looking forward to many miles in HOT areas during summer months

Got a lot of catching up to do with things I should have done but-----

Have fun at the GTG missing that for sure, hello everyone!


Ed
94 30' Breakaway #3864
30-BS-6B side entry
New Cummins 5.9L, 375+ HP
Allison 6 speed
Spartan chassis
K9DVC
Tankless water heater
06-06-2018, 01:12 PM
Mike/Cindi W
Atwood Air Command it is then... cheers

went to the Atwood Site and clicked Air Command Web Site link and what comes up...Dometic AC's with an Australian URL (although a nice pic of a SF location just north of the GGate). Thinking that they maybe were hacked, I called their main number and they answered Dometic-Atwood products.. Was not aware they are now the same company..

here's the Atwood sides current AC brochure...


M/C-W

1991 early XL-style (maybe 1 of 2?) Breakaway... but prior to that actual (XL) designation...
2nd Breakaway w/Cat 3208T 250 hp motor 4 spd MT643 Allison trans Gilig Air suspension chassis/brakes
Data Tag: 9010 3694 34-BG-1B
06-06-2018, 07:29 PM
Tom and Julie
You will still need to run 12v power to the Atwood units. Just like the Dumbetic.


1993 32' Regency Wide Body, 4 speed Allison Trans, Front Entry door, Diamond Plate aluminum roof &
1981 Euro 22' w Chevy 350 engine and TH 400 tranny
06-06-2018, 09:03 PM
L78steve
I would not travel without 2 units. A back-up will save a vacation.



1993 34 Regency WB
8.3 Cummins 300HP
06-08-2018, 11:16 AM
Mike/Cindi W
Tom/Julie, I thought the Atwood Air Command units were AC , not DC.. what am I missing here..?

also, when you purchase these roof units, are they complete? Or is there a separate lower, inside coach assembly needed also? The brochure for the Atwood Air Command says it includes a IR Remote. To me that says its a complete ready to go unit.. or..?

M/C-W


M/C-W

1991 early XL-style (maybe 1 of 2?) Breakaway... but prior to that actual (XL) designation...
2nd Breakaway w/Cat 3208T 250 hp motor 4 spd MT643 Allison trans Gilig Air suspension chassis/brakes
Data Tag: 9010 3694 34-BG-1B
06-08-2018, 10:24 PM
Rusty
quote:
Originally posted by Tom and Julie:
You will still need to run 12v power to the Atwood units. Just like the Dumbetic.


Not so


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
06-08-2018, 11:58 PM
Tom and Julie
On page 5 of the Atwood manual it says the customer must provide three cables to the rooftop, including 12v plus and minus. In the purchase description for some sellers it says inside ceiling units sold separately. I have found some sellers include everything and others try to get you with a low ball, partial assembly. As noted apparently Atwood was bought by Dometic. Unless something changes drastically I am going with Coleman for our Euro.
The compressor and fan run on AC but the digital controls and signal circuits are 12v. The control board(dc) operates relays to turn on and run the compressor, fans and heater. The IR remote energizes a dc control system. All that does not exist if you get a unit with the ceiling mounted controls like the ones from years ago: on-off, fan, and temp which is a rotary thermostat control. Not modern but you don't have to add power through the walls and ceiling. This is the difference between analog thermostats and digital ones.


1993 32' Regency Wide Body, 4 speed Allison Trans, Front Entry door, Diamond Plate aluminum roof &
1981 Euro 22' w Chevy 350 engine and TH 400 tranny
06-09-2018, 09:43 AM
Steve VW
It depends on which model you are buying.

If you buy a ceiling unit, as I did over a year ago, it will come with built in flip down remote panel. No 12v required, self contained, 110V only. I originally bought it for the Regal but it ended up in the Monarch. Since the Monarch is a ducted system, I used the existing Monarch ceiling panel. I removed the remote from the Atwood ceiling panel and reused the old wire that ran to the Dometic thermostat (both use 4 wires) and mounted it on the wall.

Some suppliers sell the complete unit with inside cover, remote and main roof unit together. Some offer them seperately. Be sure you read carefully.

If you choose a ducted model, you get a different inside panel and a separate remote for wall mounting. This unit has a slightly different thermostat which allows choice of the Atwood for heat or your coach furnace. If you choose this option, you will need 12V at the unit to operate the coach furnace module inside the Atwood unit.

Since the Dometic takeover, this may have changed. I just ordered a second bare non ducted Atwood roof unit and a separate wall thermostat for the back of the Monarch. When I get it I will report on that.

The Coleman is MUCH more noisy than the Atwood.

PS: Just checked my emails. The Atwood order was cancelled. head bang

RVpartscountry.com is not reliable. I will reorder from someone else.


9708-M0037-37MM-01
"98" Monarch 37
Spartan MM, 6 spd Allison
Cummins 8.3 325+ hp
06-10-2018, 11:22 AM
Danny Z
Steve, I got my AC unit from PPL in Texas. They have good prices, ship fast, and have real knowledgeable people for tech support.


79 Barth Classic
06-10-2018, 07:01 PM
Mike/Cindi W
What is the Atwood product # ( 15026 ?... unknown which is which model mentioned below) that comes complete, non-ducted one.. and which one did folks get, the AC-135 (16K) or the AC-150 (18K) ?


M/C-W

1991 early XL-style (maybe 1 of 2?) Breakaway... but prior to that actual (XL) designation...
2nd Breakaway w/Cat 3208T 250 hp motor 4 spd MT643 Allison trans Gilig Air suspension chassis/brakes
Data Tag: 9010 3694 34-BG-1B
06-10-2018, 09:20 PM
Rusty
quote:
Originally posted by Danny Z:
Steve, I got my AC unit from PPL in Texas. They have good prices, ship fast, and have real knowledgeable people for tech support.


Same here. And I have a disconnected 12V line coiled up in an overhead compartment, no longer needed, now I have the Atwood.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields