Home » Public Forums » GMCnet » What purpose are the refrigerator exterior louvers?
| What purpose are the refrigerator exterior louvers? [message #190159] |
Tue, 13 November 2012 13:12  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
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I understand that there is some heat generated by the coils but only in the summer is that a problem. The rest of the year it's 'free' heat.
I'd think that we could cover the louvers from the inside of the panel to keep the cold air out. During the summer, just uncover them.
Am I missing something?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: What purpose are the refrigerator exterior louvers? [message #190160 is a reply to message #190159] |
Tue, 13 November 2012 13:17  |
jknezek
Messages: 1057
Registered: December 2007
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Not to my mind. In the summer, especially in the hot and humid south, you need all the air flow you can get over those coils. I love my original fridge, never have to mess with propane or park perfectly level (we don't dry camp either!), but in the summer I start it cooling the day before we leave. The 12 volt operation is enough to keep it cold, but in the summer it won't make it cold.
Thanks,
Jeremy Knezek
1976 Glenbrook
Birmingham, AL
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| Re: [GMCnet] What purpose are the refrigerator exterior louvers? [message #190162 is a reply to message #190160] |
Tue, 13 November 2012 13:28 |
James Hupy
Messages: 6806
Registered: May 2010
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Kerry, those louvers are there to provide combustion air to the propane
burner as well as to circulate air over the coils. It would not be too
advisable to cover them when the propane burner is in use.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Tue, Nov 13, 2012 at 11:17 AM, Jeremy <jtknezek@hotmail.com> wrote:
>
>
> Not to my mind. In the summer, especially in the hot and humid south, you
> need all the air flow you can get over those coils. I love my original
> fridge, never have to mess with propane or park perfectly level (we don't
> dry camp either!), but in the summer I start it cooling the day before we
> leave. The 12 volt operation is enough to keep it cold, but in the summer
> it won't make it cold.
> --
> Thanks,
> Jeremy Knezek
> 1976 Glenbrook
> Birmingham, AL
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| Re: [GMCnet] What purpose are the refrigerator exterior louvers? [message #190171 is a reply to message #190164] |
Tue, 13 November 2012 15:48 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Should have said my fridge is a two way, 12V and 120V. Don't have to worry about combustible air or vent for the fridge.
| GALE GORMAN |
...
Yes. The way the refrigerator gets cold is by heating the gas in the tubes (propane or electric) and the gas cools as it rises. The quicker that happens the colder the box gets. If you park enough out of level, front to rear, you stop the cycle.
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Ok, I can understand that. However, why are the louvers at the BOTTOM instead of near the top of the wall where the heat rises?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
[Updated on: Tue, 13 November 2012 17:13] Report message to a moderator |
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| Re: [GMCnet] What purpose are the refrigerator exterior louvers? [message #190177 is a reply to message #190171] |
Tue, 13 November 2012 16:34 |
C Boyd
Messages: 2629
Registered: April 2006
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Sir: cause the outlet vent is in the roof..
[quote title=Kerry Pinkerton wrote on Tue, 13 November 2012 16:48]Should have said my fridge is a two way, 12V and 120V. Don't have to worry about combustible air or vent for the fridge.
[quote title=GALE GORMAN} ...
Yes. The way the refrigerator gets cold is by heating the gas in the tubes (propane or electric) and the gas cools as it rises. The quicker that happens the colder the box gets. If you park enough out of level, front to rear, you stop the cycle. [/quote}
Ok, I can understand that. However, why are the louvers at the BOTTOM instead of near the top of the wall where the heat rises?[/quote]
C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] What purpose are the refrigerator exterior louvers? [message #190178 is a reply to message #190171] |
Tue, 13 November 2012 16:31 |
powerjon
Messages: 2446
Registered: January 2004
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Kerry,
You should have a vent on top of the coach above the frig. That is
where the heat exits, the cold air enters from the bottom.
JR Wright
78 Buskirk Stretch
Michigan
>
>
> Should have said my fridge is a two way, 12V and 120V. Don't have
> to worry about combustible air or vent for the fridge.
>
> [quote title=GALE GORMAN} ...
> Yes. The way the refrigerator gets cold is by heating the gas in the
> tubes (propane or electric) and the gas cools as it rises. The
> quicker that happens the colder the box gets. If you park enough out
> of level, front to rear, you stop the cycle. [/quote}
>
> Ok, I can understand that. However, why are the louvers at the
> BOTTOM instead of near the top of the wall where the heat rises?
> --
> Kerry Pinkerton
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] What purpose are the refrigerator exterior louvers? [message #190181 is a reply to message #190171] |
Tue, 13 November 2012 16:44 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Kerry,
The side vents let cool air in, the roof vent lets hot air out.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Kerry Pinkerton
Should have said my fridge is a two way, 12V and 120V. Don't have to worry about combustible air or vent for the fridge.
[quote title=GALE GORMAN} ...
Yes. The way the refrigerator gets cold is by heating the gas in the tubes (propane or electric) and the gas cools as it rises. The
quicker that happens the colder the box gets. If you park enough out of level, front to rear, you stop the cycle. [/quote}
Ok, I can understand that. However, why are the louvers at the BOTTOM instead of near the top of the wall where the heat rises?
--
Kerry
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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] What purpose are the refrigerator exterior louvers? [message #190197 is a reply to message #190189] |
Tue, 13 November 2012 17:45 |
k2gkk
Messages: 4452
Registered: November 2009
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Cooler AND combustion air for the burner.
Heat of the fire or electric heater causes
the circulation of the air and heat upward
to the roof vent.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
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> To: gmclist@temp.gmcnet.org
> From: Pinkertonk@MCHSI.com
> Date: Tue, 13 Nov 2012 17:15:22 -0600
> Subject: Re: [GMCnet] What purpose are the refrigerator exterior louvers?
>
> Robert Mueller wrote on Tue, 13 November 2012 16:44
> > The side vents let cool air in, the roof vent lets hot air out.
>
> Ah, I get it now. Duh.
> --
> Kerry Pinkerton
> North Alabama, near Huntsville,
> 77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as an Art Deco car hauler
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| Re: [GMCnet] What purpose are the refrigerator exterior louvers? [message #190201 is a reply to message #190163] |
Tue, 13 November 2012 18:06 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
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| GALE GORMAN wrote on Tue, 13 November 2012 11:46 |
On Nov 13, 2012, at 1:12 PM, Kerry Pinkerton <Pinkertonk@MCHSI.com> wrote:
Am I missing something?
--
Kerry Pinkerton
-----------snip----------
Yes. The way the refrigerator gets cold is by heating the gas in the tubes (propane or electric) and the gas cools as it rises. The quicker that happens the colder the box gets. If you park enough out of level, front to rear, you stop the cycle.
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From what I understand, ALL GM upfitted coaches left the factory with all electric refrigerators. Other upfitters may have installed absorption (propane/electric) or compressor (all electric). The design of cabinets and venting should reflect the kind of refer being installed.
Electric refer do need some air flow this could be air from the inside or outside the coach. The early GM coaches did not come with side vents but most had them added later. (I am not sure if this was a factory directed thing or not.) Later coaches came with vents and these vents did change some over the years. The last coaches had louvers cut in the side, some low and some high on the side and no roof vents. <http://www.gmcmhphotos.com/photos/refrigerator-vents/p14139.html>
An absorption refer cabinet should have more venting and baffling to get the air flow to pass correctly over the coils. When in use, there should be draft to draw exhaust out the top vent. It also should have some kind of propane "drain" to allow any leaked propane to exit the coach... reducing the chance of fire and explosions.
Many (most???) GMC's have been upgraded(?) to three way (absorption) refers. Problem is that most cabinets have not been modified to work well (and safely) with the propane burning units.
Both my Birchs have the bottom of the cabinet level with the vented door. (As designed by Coachman for the installed absorption units.) On my 1973 xPainted D. with the GMC designed cabinet and a PO installed 3 way refer, I sealed the cabinet and installed a propane drain pipe into the wheel well. (I used an actual sink drain pipe with a 90 degree bend.) But as things go, I later replaced the refer with an all electric unit.
To much info?
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: What purpose are the refrigerator exterior louvers? [message #190310 is a reply to message #190159] |
Wed, 14 November 2012 16:12 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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| Kerry Pinkerton wrote on Tue, 13 November 2012 14:12 |
I understand that there is some heat generated by the coils but only in the summer is that a problem. The rest of the year it's 'free' heat.
I'd think that we could cover the louvers from the inside of the panel to keep the cold air out. During the summer, just uncover them.
Am I missing something?
|
Kerry,
It would seem that I know more about this than most...
The original coaches all shipped with 12/120V Norcold and no exterior venting. It was expected that the reefer - like a home unit - would be maintained by the interior of the coach and that would be maintained at comfortable levels just like a home. To this end, the reefers were installed with a 3~4' air space above and below to allow coach space air to circulate behind the reefer. This all worked fine as most of the testing was done in Michigan and by traveling test groups.
The problem came up when the coaches were used in warm and sunny places (not at all like Michigan) and parked where the sun could beat on the reefer side of the coach. That poor little 40w compressor just could not handle that and the ice cream melted. Bad, real bad..
GMC issued a "Good Will" recall. That recall authorized the dealer to install industry standard roof vents and side doors for all customers that had this problem. If you look behind my reefer, it is pretty obvious that this was an effective cobble job and that may be why the reefer access panel is about a quarter inch out square to the coach side. As the recall did not cover "paint to match", many coaches still have a door cut into the striping. The later coaches that were ordered with electric refrigeration just got vent louvers cut in the coach side and have no roof vent or side access door. A few of these show up at the larger rallies.
Ready for the funny story?
When they were done, that air space above and below for the original cooling now communicated directly with the outside world. Oh - Yeah?
Want to know when I discovered all about this?
It was the second night of out very first excursion. At that time, I had now owned the coach about a month. We spent the night at a state park in Minnesota. The campsite had electric and water, but we had no electric heat. I had installed a new 30k Suburban before departure. We set that and went to bed. It was 20°F when we got up. The Suburdan was firing as hard as it could and the floor was Coolldd. As I walked past the reefer, I could feel this fall of cold air pouring out from underneath it.
A combination of shopping bags and duck tape did a pretty good job of closing up those two vents. We still had to refill the propane for the next night.
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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| Re: What purpose are the refrigerator exterior louvers? [message #190347 is a reply to message #190310] |
Wed, 14 November 2012 20:26 |
bryant374
Messages: 563
Registered: May 2004
Location: Pleasant Valley, NY 12569
Karma: 1
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The production 1973's and early 1974's were built without refrigerator venting, this was not intended, here are the details.
The earliest preproduction and test coaches all had refrigerator vents.
A Service Bulletin was issued for 1973/4 production coaches without vents, stating that owners complaining of poor refrigerator performance could have venting retrofitted by GMC.
I spoke to John Locklin, asking why there were no vents in the early coaches, his answer was, "I forgot". John was the GMC Motorhome body engineer, the guy responsible for that item, he said there was so much going on at that time that it was one of those things that got missed. One of several things that didn't get caught until owners discovered some things that needed to be changed.
Bill Bryant
PO 1976~PB (owned 34 years)
1914 Ford (owned 70 years)
1965 Corvette (owned 39 years)
GMC Motorhome History
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