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Roof Air Conditioner [message #331340] Tue, 24 April 2018 17:19 Go to next message
Bob Wheaton is currently offline  Bob Wheaton   Canada
Messages: 23
Registered: February 2004
Location: New Brunswick, Canada
Karma: 0
Junior Member
Hi All,
Has anyone had any issues with mounting the rear roof air conditioner backwards?
I will be replacing my rear unit with a low profile Carrier Unit and will have to mount
it backwards to get it to fit. My concerns are rain and wind entering the unit while driving.
Probably won't be necessary to operate it while driving but just wondering if anyone had any problems?
Thanks,
Bob Wheaton

'78 GMC Kingsley
NB,Canada

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Re: [GMCnet] Roof Air Conditioner [message #331343 is a reply to message #331340] Tue, 24 April 2018 19:24 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
Bob,

That's the way John Sharpe mounted his rear Carrier and he doesn't have any problems with it.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808



-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of bobwheaton@hotmail.com
Sent: Tuesday, April 24, 2018 5:19 PM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Roof Air Conditioner

Hi All,
Has anyone had any issues with mounting the rear roof air conditioner backwards?
I will be replacing my rear unit with a low profile Carrier Unit and will have to mount
it backwards to get it to fit. My concerns are rain and wind entering the unit while driving.
Probably won't be necessary to operate it while driving but just wondering if anyone had any problems?
Thanks,
Bob Wheaton
--
'78 GMC Kingsley
NB,Canada



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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426

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Re: [GMCnet] Roof Air Conditioner [message #331345 is a reply to message #331343] Tue, 24 April 2018 19:49 Go to previous messageGo to next message
tphipps is currently offline  tphipps   United States
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
Senior Member
I mounted the rear A/C backward on my Avion. Needed to clear the rear clearance lights. Worked just fine while stationary on shore or generator power. Never tried it while underway.
Tom

2012 Phoenix Cruiser model 2552 KA4CSG

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Re: Roof Air Conditioner [message #331363 is a reply to message #331340] Wed, 25 April 2018 09:40 Go to previous messageGo to next message
Chris Tyler is currently offline  Chris Tyler   United States
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
Senior Member
I think the problem with the rear AC is the original duoTherm units were much shorter in length and had a different footprint.

Areodynamics and aesthetics aside, I think the only problem is having the condensor fins facing forward, they may tend to scoop up dust , debris and bend fins.

76 Glenbrook

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Re: [GMCnet] Roof Air Conditioner [message #331364 is a reply to message #331363] Wed, 25 April 2018 09:49 Go to previous messageGo to next message
emerystora is currently offline  emerystora   United States
Messages: 4442
Registered: January 2004
Karma: 13
Senior Member
Many people have done this over the years and also run them going down the road with their Onan running.
I recall the Penguins were one of them that people mounted backwards.

Emery Stora

> On Apr 25, 2018, at 8:40 AM, Chris Tyler wrote:
>
> I think the problem with the rear AC is the original duoTherm units were much shorter in length and had a different footprint.
>
> Areodynamics and aesthetics aside, I think the only problem is having the condensor fins facing forward, they may tend to scoop up dust , debris and
> bend fins.
> --
> 76 Glenbrook
>
> _______________________________________________
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Re: [GMCnet] Roof Air Conditioner [message #331366 is a reply to message #331340] Wed, 25 April 2018 10:31 Go to previous messageGo to next message
Eric Mears is currently offline  Eric Mears   United States
Messages: 5
Registered: May 2017
Karma: 1
Junior Member
I'm not sure about other air conditioners, but the Atwood Air Command
manual specifically states not to install them backwards:

"- The front of the unit MUST face the direction of travel; failure to
follow this instruction will result in damage to the condenser fans."

http://www.atwoodmobile.com/manuals/ac/MPD_15078_AC_IOM_DUCTED_02_05_2016_Rev_9.pdf

Eric
(no GMC, but my friend has one)


On Tue, Apr 24, 2018 at 3:19 PM, bobwheaton@hotmail.com <
bobwheaton@hotmail.com> wrote:

> Hi All,
> Has anyone had any issues with mounting the rear roof air conditioner
> backwards?
> I will be replacing my rear unit with a low profile Carrier Unit and will
> have to mount
> it backwards to get it to fit. My concerns are rain and wind entering the
> unit while driving.
> Probably won't be necessary to operate it while driving but just wondering
> if anyone had any problems?
> Thanks,
> Bob Wheaton
> --
> '78 GMC Kingsley
> NB,Canada
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Re: [GMCnet] Roof Air Conditioner [message #331368 is a reply to message #331366] Wed, 25 April 2018 11:17 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
Probably because the fans will spin backwards.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Eric Mears
Sent: Wednesday, April 25, 2018 10:32 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Roof Air Conditioner

I'm not sure about other air conditioners, but the Atwood Air Command
manual specifically states not to install them backwards:

"- The front of the unit MUST face the direction of travel; failure to
follow this instruction will result in damage to the condenser fans."

http://www.atwoodmobile.com/manuals/ac/MPD_15078_AC_IOM_DUCTED_02_05_2016_Rev_9.pdf

Eric
(no GMC, but my friend has one)


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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426

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Re: [GMCnet] Roof Air Conditioner [message #331370 is a reply to message #331368] Wed, 25 April 2018 11:38 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
Senior Member
The Fan can free wheel backwards when not in use, but minimal.

On Wed, Apr 25, 2018 at 9:17 AM, Rob Mueller
wrote:

> Probably because the fans will spin backwards.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Eric
> Mears
> Sent: Wednesday, April 25, 2018 10:32 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Roof Air Conditioner
>
> I'm not sure about other air conditioners, but the Atwood Air Command
> manual specifically states not to install them backwards:
>
> "- The front of the unit MUST face the direction of travel; failure to
> follow this instruction will result in damage to the condenser fans."
>
> http://www.atwoodmobile.com/manuals/ac/MPD_15078_AC_IOM_
> DUCTED_02_05_2016_Rev_9.pdf
>
> Eric
> (no GMC, but my friend has one)
>
>
> _______________________________________________
> 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] Roof Air Conditioner [message #331372 is a reply to message #331370] Wed, 25 April 2018 11:57 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
I doubt the backwards freewheeling will be "minimal" at 60+ mph going down the freeway! :-)

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Jim Kanomata
Sent: Wednesday, April 25, 2018 11:39 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Roof Air Conditioner

The Fan can free wheel backwards when not in use, but minimal.

On Wed, Apr 25, 2018 at 9:17 AM, Rob Mueller
wrote:

> Probably because the fans will spin backwards.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Eric
> Mears
> Sent: Wednesday, April 25, 2018 10:32 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Roof Air Conditioner
>
> I'm not sure about other air conditioners, but the Atwood Air Command
> manual specifically states not to install them backwards:
>
> "- The front of the unit MUST face the direction of travel; failure to
> follow this instruction will result in damage to the condenser fans."
>
> http://www.atwoodmobile.com/manuals/ac/MPD_15078_AC_IOM_
> DUCTED_02_05_2016_Rev_9.pdf
>
> Eric
> (no GMC, but my friend has one)
>
>
> _______________________________________________
> 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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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426

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Re: [GMCnet] Roof Air Conditioner [message #331374 is a reply to message #331372] Wed, 25 April 2018 12:02 Go to previous messageGo to next message
Will Albers is currently offline  Will Albers   United States
Messages: 183
Registered: November 2017
Location: Detroit MI (Belleville)
Karma: 2
Senior Member
Is freewheeling the issue, or the fact that while running it in motion, the
incoming air pressure may slow or stop the fan?

On Wed, Apr 25, 2018 at 12:57 PM, Rob Mueller
wrote:

> I doubt the backwards freewheeling will be "minimal" at 60+ mph going down
> the freeway! :-)
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Jim
> Kanomata
> Sent: Wednesday, April 25, 2018 11:39 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Roof Air Conditioner
>
> The Fan can free wheel backwards when not in use, but minimal.
>
> On Wed, Apr 25, 2018 at 9:17 AM, Rob Mueller
> wrote:
>
>> Probably because the fans will spin backwards.
>>
>> Regards,
>> Rob M.
>> The Pedantic Mechanic
>> Sydney, Australia
>> AUS '75 Avion - The Blue Streak TZE365V100428
>> USA '75 Avion - Double Trouble TZE365V100426
>> USA '77 Kingsley - TZE 267V100808
>>
>>
>> -----Original Message-----
>> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Eric
>> Mears
>> Sent: Wednesday, April 25, 2018 10:32 AM
>> To: gmclist@list.gmcnet.org
>> Subject: Re: [GMCnet] Roof Air Conditioner
>>
>> I'm not sure about other air conditioners, but the Atwood Air Command
>> manual specifically states not to install them backwards:
>>
>> "- The front of the unit MUST face the direction of travel; failure to
>> follow this instruction will result in damage to the condenser fans."
>>
>> http://www.atwoodmobile.com/manuals/ac/MPD_15078_AC_IOM_
>> DUCTED_02_05_2016_Rev_9.pdf
>>
>> Eric
>> (no GMC, but my friend has one)
>>
>>
>> _______________________________________________
>> 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
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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1978 Palm Beach.
Detroit Michigan

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Re: [GMCnet] Roof Air Conditioner [message #331376 is a reply to message #331374] Wed, 25 April 2018 12:42 Go to previous messageGo to next message
mghamms is currently offline  mghamms   United States
Messages: 466
Registered: March 2016
Location: Ware, Massachusetts
Karma: 2
Senior Member
I don't like the look of the backward mounting.
I used an Atwood commander 15000 heat pump in the mid and a brisk 13500 in the back.

1977 Kingsley 455 as stock as it gets except lots of Ragusa parts

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Re: [GMCnet] Roof Air Conditioner [message #331383 is a reply to message #331374] Wed, 25 April 2018 16:26 Go to previous messageGo to next message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
Probably both.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Will
Sent: Wednesday, April 25, 2018 12:02 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Roof Air Conditioner

Is freewheeling the issue, or the fact that while running it in motion, the
incoming air pressure may slow or stop the fan?

On Wed, Apr 25, 2018 at 12:57 PM, Rob Mueller
wrote:

> I doubt the backwards freewheeling will be "minimal" at 60+ mph going down
> the freeway! :-)
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> Sydney, Australia
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
>
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Jim
> Kanomata
> Sent: Wednesday, April 25, 2018 11:39 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Roof Air Conditioner
>
> The Fan can free wheel backwards when not in use, but minimal.
>
> On Wed, Apr 25, 2018 at 9:17 AM, Rob Mueller
> wrote:
>
>> Probably because the fans will spin backwards.
>>
>> Regards,
>> Rob M.
>> The Pedantic Mechanic
>> Sydney, Australia
>> AUS '75 Avion - The Blue Streak TZE365V100428
>> USA '75 Avion - Double Trouble TZE365V100426
>> USA '77 Kingsley - TZE 267V100808
>>
>>
>> -----Original Message-----
>> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Eric
>> Mears
>> Sent: Wednesday, April 25, 2018 10:32 AM
>> To: gmclist@list.gmcnet.org
>> Subject: Re: [GMCnet] Roof Air Conditioner
>>
>> I'm not sure about other air conditioners, but the Atwood Air Command
>> manual specifically states not to install them backwards:
>>
>> "- The front of the unit MUST face the direction of travel; failure to
>> follow this instruction will result in damage to the condenser fans."
>>
>> http://www.atwoodmobile.com/manuals/ac/MPD_15078_AC_IOM_
>> DUCTED_02_05_2016_Rev_9.pdf
>>
>> Eric
>> (no GMC, but my friend has one)
>>
>>
>> _______________________________________________
>> 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
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426

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Re: [GMCnet] Roof Air Conditioner [message #331384 is a reply to message #331376] Wed, 25 April 2018 16:30 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
Senior Member
Blades that are curved to pull will be less effected by air coming at
opposit direction, plus the condenser fins are dense and there is enough
turbulense on the roof with other objects.

On Wed, Apr 25, 2018 at 10:42 AM, Mike Hamm wrote:

> I don't like the look of the backward mounting.
> I used an Atwood commander 15000 heat pump in the mid and a brisk 13500 in
> the back.
> --
> 1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
>
> _______________________________________________
> 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] Roof Air Conditioner [message #331389 is a reply to message #331383] Wed, 25 April 2018 18:01 Go to previous message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
This has been a really interesting thread, and a lot of what has been written is accurate as far as I know. But, as a sailor of wind powered vessels and a naval architect, I think that any problem with the ram air effect on the condenser fan could be erased but putting an obstruction in front of the air intake buy no less than a fan diameter. That would end that.

Now all you need is a good ladder and a roof pod.

Matt

Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

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