Home » Public Forums » GMCnet » Opinions Wanted - Rooftop AC
| Opinions Wanted - Rooftop AC [message #345129] |
Thu, 11 July 2019 10:07  |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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So when I bought my coach several years ago, it had what I believe is an early OEM rooftop AC, but I haven't been able to find out much info on it. It's a "John E. Mitchell Co." unit rated at 13.5k BTU. It runs great, but uses a lot of power based on the fact that if it is above 95 degrees, it will trip a 20amp breaker in the shorepower panel, even set to low. (For some reason though, the genset seems to run it fine.... Even on high when it is 105+, it never trips the 20amp on the onboard panel whether on shorepower or the genset)
Anyway, I figured when we bought the coach, we would run the Mitchell AC for a few years, then get something newer down the road. Last year, we had a week long trip planned to Florida in August, and I figured it would be a good time to change out the old AC, so I picked up a 15K btu Atwood Air Command. But, one thing led to another, and I was never able to perform the swap before the trip, so we ran the Mitchell AC. It ran all the way from here in Texas to FL on the genset, spent a week at the beach there (hooked to a 50amp service), and then ran it all the way home, and the Mitchell AC never missed a beat.
So now, here we are, a year later, and this coming August we are again going to Florida, and I'm in the same boat of considering to change out the Mitchell for the Air Command, (which has been sitting on a shelf since last year) but now based on how well the Mitchell unit ran, I'm sort of on the fence on whether or not I should. My thoughts are this:
(Let me preface this with the fact that my coach lived most of it's life in a cooler climate than where we live here in Texas, so I don't sense the Mitchell AC had much use)
1. The Mitchell AC is obviously built like a tank to last 45 years and still work great. Would a newer Atwood be more reliable? I realize it is doubtful the Atwood would last 45 years, but say over the next 5 or 10 years, which unit would most likely give me less trouble? I'm also weighing the fact that I have no problem doing minor repairs on either....
I could probably carry a spare run capacitor, or contactor or other spares for the Mitchell unit and swap them out if needed. OTOH, I assume the Atwood is more dependent on electronics, so in the event that either one had an issue, I could probably fix the Mitchell with less down time... But then, the Atwood is new, so it may run trouble-free for the foreseeable future, which makes repairing it a moot point.
2. The Mitchell unit is rated at 13.5K btu, the Atwood is 15k, but are the ratings equivalent? In my experience, it would not be unusual for things that were built back then to be somewhat under-rated... Which unit do you think would ultimately cool better?
Those are the main things I'm considering... But also weighing in on my decision are the next few questions:
3. On high, the Mitchell unit is somewhat loud, but at low cool, it really is pretty quiet and low tends to do the job most times on our coach. The compressor sounds more like an old sealed industrial refrigeration unit (which is probably what it is, based on the history of what I read on the Mitchell Co.) than an AC compressor... I've heard the Atwood is quiet as well. Which do you feel would produce the least amt of noise?
4. The Atwood should put less load/stress on the genset, has a heatpump, wireless remote, etc.... The Mitchell can't match any of these.
So that's kind of where my head is at... Since the coach only has one AC, our vacation enjoyment is going to be pretty tied to how well the AC performs, as the wife and our young children are not going to handle being in Florida, near the beach, in August in an un-air-conditioned coach.... Not to mention the drive back and forth through southern Mississippi, Alabama, East Texas, etc. with only the dash AC, which as we all know, does not cool well stock.
I've also toyed with the idea of putting in the Air Command in the center, and adding a second unit in the rear in place of the fantastic fan we have back there for some redundancy.... But I like the simplicity of having one unit, and it's less weight/drag on the roof... Since one unit seems to cool my coach well, would you trade redundancy for simplicity?
Going with 2 units, I've read several of the ACs available now will fit in the rear opening mounted backwards, but does anyone know if an Atwood 13.5k BTU unit would fit back there mounted forward? If not, are there any current units available that fit mounted forward?
Anyway, sorry for the long post and thanks in advance for your opinion, info, etc.
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] Opinions Wanted - Rooftop AC [message #345131 is a reply to message #345129] |
Thu, 11 July 2019 10:44  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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The newer units are more efficient and quiet, as the compressor is more
advanced. Your gambling with time.
It only takes about a hour to swap it.
On Thu, Jul 11, 2019 at 8:32 AM Mark Sawyer via Gmclist <
gmclist@list.gmcnet.org> wrote:
> So when I bought my coach several years ago, it had what I believe is an
> early OEM rooftop AC, but I haven't been able to find out much info on it.
> It's a "John E. Mitchell Co." unit rated at 13.5k BTU. It runs great, but
> uses a lot of power based on the fact that if it is above 95 degrees, it
> will trip a 20amp breaker in the shorepower panel, even set to low. (For
> some reason though, the genset seems to run it fine.... Even on high when
> it
> is 105+, it never trips the 20amp on the onboard panel whether on
> shorepower or the genset)
>
> Anyway, I figured when we bought the coach, we would run the Mitchell AC
> for a few years, then get something newer down the road. Last year, we had a
> week long trip planned to Florida in August, and I figured it would be a
> good time to change out the old AC, so I picked up a 15K btu Atwood Air
> Command. But, one thing led to another, and I was never able to perform
> the swap before the trip, so we ran the Mitchell AC. It ran all the way
> from
> here in Texas to FL on the genset, spent a week at the beach there (hooked
> to a 50amp service), and then ran it all the way home, and the Mitchell AC
> never missed a beat.
>
> So now, here we are, a year later, and this coming August we are again
> going to Florida, and I'm in the same boat of considering to change out the
> Mitchell for the Air Command, (which has been sitting on a shelf since
> last year) but now based on how well the Mitchell unit ran, I'm sort of on
> the
> fence on whether or not I should. My thoughts are this:
>
> (Let me preface this with the fact that my coach lived most of it's life
> in a cooler climate than where we live here in Texas, so I don't sense the
> Mitchell AC had much use)
>
> 1. The Mitchell AC is obviously built like a tank to last 45 years and
> still work great. Would a newer Atwood be more reliable? I realize it is
> doubtful the Atwood would last 45 years, but say over the next 5 or 10
> years, which unit would most likely give me less trouble? I'm also weighing
> the fact that I have no problem doing minor repairs on either....
> I could probably carry a spare run capacitor, or contactor or other
> spares for the Mitchell unit and swap them out if needed. OTOH, I assume
> the
> Atwood is more dependent on electronics, so in the event that either one
> had an issue, I could probably fix the Mitchell with less down time... But
> then, the Atwood is new, so it may run trouble-free for the foreseeable
> future, which makes repairing it a moot point.
>
> 2. The Mitchell unit is rated at 13.5K btu, the Atwood is 15k, but are the
> ratings equivalent? In my experience, it would not be unusual for things
> that were built back then to be somewhat under-rated... Which unit do you
> think would ultimately cool better?
>
> Those are the main things I'm considering... But also weighing in on my
> decision are the next few questions:
>
> 3. On high, the Mitchell unit is somewhat loud, but at low cool, it really
> is pretty quiet and low tends to do the job most times on our coach. The
> compressor sounds more like an old sealed industrial refrigeration unit
> (which is probably what it is, based on the history of what I read on the
> Mitchell Co.) than an AC compressor... I've heard the Atwood is quiet as
> well. Which do you feel would produce the least amt of noise?
>
> 4. The Atwood should put less load/stress on the genset, has a heatpump,
> wireless remote, etc.... The Mitchell can't match any of these.
>
> So that's kind of where my head is at... Since the coach only has one AC,
> our vacation enjoyment is going to be pretty tied to how well the AC
> performs, as the wife and our young children are not going to handle being
> in Florida, near the beach, in August in an un-air-conditioned coach....
> Not to mention the drive back and forth through southern Mississippi,
> Alabama, East Texas, etc. with only the dash AC, which as we all know, does
> not
> cool well stock.
>
> I've also toyed with the idea of putting in the Air Command in the center,
> and adding a second unit in the rear in place of the fantastic fan we have
> back there for some redundancy.... But I like the simplicity of having
> one unit, and it's less weight/drag on the roof... Since one unit seems to
> cool my coach well, would you trade redundancy for simplicity?
>
> Going with 2 units, I've read several of the ACs available now will fit in
> the rear opening mounted backwards, but does anyone know if an Atwood 13.5k
> BTU unit would fit back there mounted forward? If not, are there any
> current units available that fit mounted forward?
>
> Anyway, sorry for the long post and thanks in advance for your opinion,
> info, etc.
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Opinions Wanted - Rooftop AC [message #345132 is a reply to message #345131] |
Thu, 11 July 2019 11:14 |
mghamms
Messages: 466
Registered: March 2016
Location: Ware, Massachusetts
Karma: 2
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Senior Member |
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I made the same preplacment you did with the exception I as going to put the new one in the back.
When I realized it interfered withe the roof lights it when replaced the old front one.
I still have it if anyone is interstellar, FREE.
I put a Brisk in the back.
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
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| Re: [GMCnet] Opinions Wanted - Rooftop AC [message #345135 is a reply to message #345132] |
Thu, 11 July 2019 11:46 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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Senior Member |
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I have the Atwood and it seems to be fine BUT I don't have enough time on it to give any kind of recommendation pro or con. The older units certainly seemed to be more robust than the new ones-just weigh the two and notice the huge difference. If you can mount the new unit while keeping the old one functioning without any major work, I think that's the direction I'd go. The extra weight and minimal drag would be a small price to pay IMHO. Besides, you may run into a situation where the single A/C won't be adequate and you'll be glad you have the extra cooling. Just my thoughts,
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: Opinions Wanted - Rooftop AC [message #345139 is a reply to message #345129] |
Thu, 11 July 2019 13:01 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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See my other post. I put the air
Command up front as my main unit. The original one in my
Coach on the rear fit and did not interfear. Some new one's do. Your "mitchell". Seems in my kind not to be original.
Coach's are freaking hot. Lots of glass is good, but A/C is key for comfort. I like having two. Both for quick cooling, but piece of mind on having a backup. I hope to get my dash a/c upgraded so I have 3 choices for air.
The heat pump is nice in MN. I still have a working oem furnace. But spring/fall camping the atwood heat pump does all the work to keep coach comfortable. Below 40 degrees the furnace has to take over.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Opinions Wanted - Rooftop AC [message #345141 is a reply to message #345129] |
Thu, 11 July 2019 14:46 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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Thanks everyone for their feedback.... I am liking the idea of leaving the existing AC and adding the new one more and more.... Have to take a look to see if either will fit in the rear...
While I was not really able to find anything on the internet concerning a Mitchell RV AC, I was able to find some information on the company... If you're a history buff like me, you might find this quick synopsis interesting: (Turns out I've also driven by the factory over in Dallas... It still stands, though it is loft apartments now 
So the John E Mitchell Co started off building agricultural machines during the 20s. At the start of WWII, they changed over to manufacture munitions for the Navy. Due to the war, they started running the plant 24 hours a day. However, they found the night-shift workers were having a lot of trouble sleeping during the day during the summer, due to the heat here in north Texas. The company ended up manufacturing "air conditioners" (really, they were swamp coolers) for the night shift workers, which they then sold below cost to allow the employees to sleep during the day. One thing led to another, and the company saw the market for this sort of thing, and switched over to primarily making AC components for cars after the war. From what I read, the powers at the big 3, (being from Detroit or other northern climates) did not understand their was a market for an AC system in a car. Mitchell was one of several companies (all located near Dallas, go figure) that built aftermarket AC systems for mostly luxury cars like Cadillac, Packard, etc., and I believe they were marketed as a dealer option here in the south.
Mitchell was also involved in the creation of the "ICEE" slushes you see all over. They designed and built the refrigeration units they used, and ICEE was originally division in the Mitchell co, but they sold it off sometime during the 70s. With the big 3 starting to offer AC as a factory option, Mitchell eventually closed sometime in the late 70s.
Pretty interesting, I thought...
lqqkatjon: are you saying you don't believe the Mitchell unit was original to the coach? I just sort of assumed it was based on the loose affiliation Mitchell had with the automakers for car ACs. Anyone else on here have a rooftop like this? It doesn't say Mitchell anywhere on the exposed portion of the indoor unit... I had to pull the shroud to see the manufacturer label. A previous owner had replaced the external shroud, and it also has no markings indicating who made it....
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] Opinions Wanted - Rooftop AC [message #345142 is a reply to message #345139] |
Thu, 11 July 2019 14:44 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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You need to not wait till it gets hot in the coach to turn on the A/C,
Once the interior furniture absorbs heat, it take a lot to pull the heat
out from the walls and furniture.
On Thu, Jul 11, 2019 at 11:22 AM Jon Roche via Gmclist <
gmclist@list.gmcnet.org> wrote:
> See my other post. I put the air
> Command up front as my main unit. The original one in my
> Coach on the rear fit and did not interfear. Some new one's do.
> Your "mitchell". Seems in my kind not to be original.
>
>
> Coach's are freaking hot. Lots of glass is good, but A/C is key for
> comfort. I like having two. Both for quick cooling, but piece of mind on
> having a backup. I hope to get my dash a/c upgraded so I have 3 choices
> for air.
>
> The heat pump is nice in MN. I still have a working oem furnace. But
> spring/fall camping the atwood heat pump does all the work to keep coach
> comfortable. Below 40 degrees the furnace has to take over.
>
>
> --
> Jon Roche
> 75 palm beach
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Opinions Wanted - Rooftop AC [message #345143 is a reply to message #345141] |
Thu, 11 July 2019 14:58 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Yours being a 73-
Painted desert. I can't say. I am not familiar
Enough with the 73-74. Seems lots of odd things.
My 75 had a duo-therm. See them in most coaches. Have helped swap a few and they are the same. So I know those are original.
Yours might be?? But it is not what I usually see:
Search photos and you always see same A/C.
But in 73 I have seen alternator on the right side. Kohler generators. All sorts of oddities.
http://lqqkatjon.blogspot.com/2015/04/blog-post_19.html?m=1
There is some photos
Of
My A/C swap.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Opinions Wanted - Rooftop AC [message #345147 is a reply to message #345129] |
Thu, 11 July 2019 15:40 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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The newer machines should have a scroll compressor (ask the vendor) which is somewhat more efficient than a piston unit.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Opinions Wanted - Rooftop AC [message #345165 is a reply to message #345129] |
Fri, 12 July 2019 08:16 |
Scott Nutter
Messages: 782
Registered: January 2015
Location: Houston/San Diego
Karma: 4
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Senior Member |
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Mark,
I have the Atwood up front, and a Coleman in the rear(bedroom).
Even in the hottest Texas days I don't need to run both at the same time.
I think you will really like the Atwood, especially in auto fan speed mode. It is the quietest AC I've seen.
Scott.
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI
Houston, Texas
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| Re: Opinions Wanted - Rooftop AC [message #345172 is a reply to message #345129] |
Fri, 12 July 2019 08:54 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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I did not know Mitchell made rooftop ACs, but we did have a dehumidifier by them as a kid. Buult like a tank.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Opinions Wanted - Rooftop AC [message #345183 is a reply to message #345172] |
Fri, 12 July 2019 11:26 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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John,
Mitchell was bought out by Colman, from what other SOB shops tell me.
On Fri, Jul 12, 2019 at 6:54 AM John R. Lebetski via Gmclist <
gmclist@list.gmcnet.org> wrote:
> I did not know Mitchell made rooftop ACs, but we did have a dehumidifier
> by them as a kid. Buult like a tank.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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