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09-10-2004, 07:21 AM
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#1
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Rivet Master
1991 34' Excella
Princeton
, New Jersey
Join Date: Aug 2003
Posts: 7,070
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Refrigerator temp rising over time
My refrigerator temperature rises the longer the refrigerator is on, if the outside temperature is above 80 degrees. When I first turn thr box on it will come down to a reasonable temperature, 35 degrees, in about a day. After several days the temperature will climb and can reach 49 degrees. I have removed the box and insulated the sides in such a way that there is zero clearance thinking the exposed side to the high temperature that exists in the back of the box was effecting the box. This did not have a notisable effect. I have installed a fan on the coils. This did not have a notisable effect. I contacted Dometic and they acknowledge this as a problem under some conditions. They sent me an installation manual addressing this problem that required no more than a 1 in. clearance between the rear of the coils and the wall to the rear of the box. This has never been accomplished in any Airstream, so my question. Do you notice an increase in temperature over time in your refrigerator?
This is the second refrigerator that had acted this way in this trailer.
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles
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09-10-2004, 12:44 PM
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#2
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Rivet Master
2019 25' Flying Cloud
Airstream - Other
Airstream - Other
North Central Texas
, USA
Join Date: Jan 2004
Posts: 1,003
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What part of the country are you located in?? Is this something you've noticed this past summer or is it year round?
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09-10-2004, 01:28 PM
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#3
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Rivet Master
1991 34' Excella
Princeton
, New Jersey
Join Date: Aug 2003
Posts: 7,070
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I live in NJ but the problem is not location sensitive, only outside temperatures that are about 80 degrees anywhere. In fact if I leave the thermostate set where I would normally have it set for summer operation and the temperature drops below 75 degrees the box will freeze dropping to 29 last weekend.
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles
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09-10-2004, 01:53 PM
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#4
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3 Rivet Member
Join Date: Oct 2003
Posts: 132
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HowieE
It sounds like a clogged roof vent or at least the hot air generated by the coils is not venting. Perhaps the hot air that should rise and exit at the top of the vent shaft is not getting out causing a build-up of heat in the vent shaft over time and therefore the inability of the air circulation to cool the coils sufficiently to cool the refrigerator.
Rick
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09-10-2004, 01:58 PM
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#5
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3 Rivet Member
Join Date: Oct 2003
Posts: 132
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Have you noticed a performance difference between propane and electric?
Rick
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09-10-2004, 02:11 PM
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#6
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Rivet Master
1991 34' Excella
Princeton
, New Jersey
Join Date: Aug 2003
Posts: 7,070
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The vent is clear and there is no differance between gas and electric.
It is Dometic's comment that the refrigerator will not work in high ambient temperatures with more than 1 in. clearance behind the coils that I am looking for conformation of from others. Since all Airstreams have that wide area behind the refrigerator they should all experience the same problem.
I had hoped a fan word cause enough circulation but it did not.
I will be on the road till Tuesday before I can respond to any additional comments.
Thanks
HowieE
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles
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09-10-2004, 03:50 PM
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#7
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Contributing Member
2018 Interstate Grand Tour Ext
Austin (Hays County)
, Texas
Join Date: Jun 2002
Posts: 7,164
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Vent area
The only place that there needs to be no more than 1" clearance is right at the fins. Anywhere else is of no concern. The clearance at the fins needs to be small so that the rising air mostly goes through the fins.
In my Airstream, there is a plywood "shelf" right at fin level that meets the 1" clearance criteria. I do have a thermostatically-operated fan, but the box cools nicely without the fan. It does cool down faster with the fan operating. My fan is in the bottom and augments the thermal air currents across the fins.
My former TrailManor had very poor venting and myself and a lot of other owners used aluminum sheet to direct the airflow over the fins. That change made the boxes operate very well when they cooled very poorly before.
RV Mobile has some good graphics that show good and bad venting. They like to see the baffles with 1/4" of the fins for best performance.
__________________
John W. Irwin
2018 Interstate GT, "Sabre-Dog V"
WBCCI #9632
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09-11-2004, 04:19 AM
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#8
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3 Rivet Member
Join Date: Oct 2003
Posts: 132
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Pahaska, Wonderful graphic!
I am stumped. How could Dometic sell an appliance that performs poorly in temperatures most of us experience during our camping.
Rick
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09-11-2004, 04:24 AM
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#9
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3 Rivet Member
1993 29' Excella
Jonesboro
, Louisiana
Join Date: Apr 2002
Posts: 125
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For what it's worth, my frig. works ok in the Airstream. I did put a thermostaticly controlled fan in the bottom to gently move the air to the top and it helps a lot. Have you checked the door gaskets for air leaks? It sounds like the losses exceed the cooling capacity. One or the other has to be addressed. A clogged vent would not be good as would anything that can restrict the flow of air into and up the frig. compartment. I have to admit that my new frig. does not work as well as the old one that I replaced but it is satisfactory. The new design that permits off level operation somewhat does not do much for thermal efficiency-everything must be just right for it to work well. One last thought, be sure the frig. is level when you level the trailer. Check it with a bubble inside the freezer compartment on the shelf.
Good Luck,
__________________
James Schmidt
29 ft Excello 1000
97 Expedition/Hensley Hitch/
McKesh mirrors
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09-11-2004, 10:06 AM
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#10
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Contributing Member
2018 Interstate Grand Tour Ext
Austin (Hays County)
, Texas
Join Date: Jun 2002
Posts: 7,164
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Some poor Airstream venting
Quote:
Originally Posted by Rick Alston
Pahaska, Wonderful graphic!
I am stumped. How could Dometic sell an appliance that performs poorly in temperatures most of us experience during our camping.
Rick
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The current Airstream trailers under 25' are prime examples of poor venting as shown in the bottom graphic on
the RV Mobile page That is the reason for the noisy fan that has resulted in numerous posts on this forum.
My previous 22' International not only suffered from the noisy fan syndrome (I replaced the fan, baffled it, and ran it at part speed), it also suffered from the vents being partially blocked by door being open. The 22' Safari still has that problem. Shame is that in both the 22' International and 22' Safari, the situation could have been greatly improved by simply locating the upper vents somewhat higher on the trailer side. As it is, the fins are in a pocket of hot air and depend on the fan to move any air at all.
__________________
John W. Irwin
2018 Interstate GT, "Sabre-Dog V"
WBCCI #9632
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09-11-2004, 11:24 AM
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#11
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Rivet Master
2006 28' Safari SE
Currently Looking...
Colorado Springs
, Colorado
Join Date: Jun 2003
Posts: 703
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Thermostatically controlled fans?
John & James, Tell me more about the fans you installed. Where you have them mounted, power connection and brand. Our refrigerator in the 25' CCD works great compared to our 22' (much quieter also), but there is always room for improvement especially in AZ.
Thanks,
Ken
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4CU Charter Member
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09-13-2004, 03:56 AM
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#12
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3 Rivet Member
1993 29' Excella
Jonesboro
, Louisiana
Join Date: Apr 2002
Posts: 125
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Quote:
Originally Posted by silverback
John & James, Tell me more about the fans you installed. Where you have them mounted, power connection and brand. Our refrigerator in the 25' CCD works great compared to our 22' (much quieter also), but there is always room for improvement especially in AZ.
Thanks,
Ken
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Ken,
The fan that I installed is of the homemade variety. I happened to have and old computer type muffin fan that would operaten on 12 volts. I installed it in a small box and equiped it with and on-off switch and an old window a/c unit thermostat. It was installed on the floor, just in front of the coils in the outside frig. compartment. It runs automatically, operates on 12 volts from the frig. wiring and gently moves the air upward across the coils. I realize that it would be more effective if it had been mounted in the top of the vent but my choice was much easier to install and seems to work fine. My AS does not have any baffles as recommended in the drawings that John posted. It also has considerable space at the bottom, between the coils and the outside wall of the trailer. I wonder what Airstream has to say about this problem and why they build units this way.
James
__________________
James Schmidt
29 ft Excello 1000
97 Expedition/Hensley Hitch/
McKesh mirrors
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09-13-2004, 06:06 AM
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#13
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3 Rivet Member
Join Date: Oct 2003
Posts: 132
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Pahaska, and all
I looked at the diagram you referenced, and it seems that a simple fix is in order.
First, add a light weight alluminum deflector at the top of the vent shaft to direct the air flow towards the top of the vent louvers on the skin. Instead of mounting the deflector on the refrigerator unit or walls, perhaps mounting the deflector to the vent panel would be easiest; this means that when you remove the vent panel the deflector would come with it. Maybe attach the light weight alluminum deflector to the panel with rivets.
Second, add a fan at the bottom of the unit to drive cool air up in the direction of the fins and the deflector to force air over the coils and out of the vent.
Rick
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09-14-2004, 03:40 AM
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#14
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3 Rivet Member
1993 29' Excella
Jonesboro
, Louisiana
Join Date: Apr 2002
Posts: 125
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Rick,
Help me here. What are you referring to as the vent panel? I'm not sure what you mean here.
Jim
__________________
James Schmidt
29 ft Excello 1000
97 Expedition/Hensley Hitch/
McKesh mirrors
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09-14-2004, 07:06 AM
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#15
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3 Rivet Member
Join Date: Oct 2003
Posts: 132
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Jim,
I am under the impression you have the "Bad Venting 2" refrigerator setup as shown in the graphic provider by Pahaska. Is that right? If not, what is your setup?
Rick
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09-14-2004, 07:20 AM
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#16
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3 Rivet Member
1993 29' Excella
Jonesboro
, Louisiana
Join Date: Apr 2002
Posts: 125
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Quote:
Originally Posted by Rick Alston
Jim,
I am under the impression you have the "Bad Venting 2" refrigerator setup as shown in the graphic provider by Pahaska. Is that right? If not, what is your setup?
Rick
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Rick,
Mine is more like bad venting 1, I am not at all sure what is behind the frig and near the top as I have never seen it. My frig is a large one not the double door type but has two doors. I was confused about where you recommended installing the baffle but I think we are talking about two different models.
thanks,
Jim
__________________
James Schmidt
29 ft Excello 1000
97 Expedition/Hensley Hitch/
McKesh mirrors
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09-14-2004, 10:53 AM
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#17
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3 Rivet Member
Join Date: Oct 2003
Posts: 132
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Jim
Ok, now I got the correct picture. If both bottom and top areas are free and clear, then the only thing I can think of is that you need to do away with the dead air space in Bad Venting 1 because you are not able to create the chimney effect needed to move the hot air out fast enough. In addition, you can minimize the suns effect on the trailer by parking in the shade or at least shading the refergerator side of the trailer from the direct sun; but you probably know that. The awning will also provide beneficial shade to help cool the skin of the trailer - assuming the refrigerator is on that side of the trailer. I figure if the skin gets hot and heats the coils, the refrigerator must work harder to dissipate the heat.
I still believe you have a problem with the build-up of heat because of the way you described what happens. Do you know if you can get to the dead air space to add a deflector?
Rick
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09-23-2004, 06:16 AM
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#18
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3 Rivet Member
1993 29' Excella
Jonesboro
, Louisiana
Join Date: Apr 2002
Posts: 125
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Quote:
Originally Posted by Rick Alston
Jim
Ok, now I got the correct picture. If both bottom and top areas are free and clear, then the only thing I can think of is that you need to do away with the dead air space in Bad Venting 1 because you are not able to create the chimney effect needed to move the hot air out fast enough. In addition, you can minimize the suns effect on the trailer by parking in the shade or at least shading the refergerator side of the trailer from the direct sun; but you probably know that. The awning will also provide beneficial shade to help cool the skin of the trailer - assuming the refrigerator is on that side of the trailer. I figure if the skin gets hot and heats the coils, the refrigerator must work harder to dissipate the heat.
I still believe you have a problem with the build-up of heat because of the way you described what happens. Do you know if you can get to the dead air space to add a deflector?
Rick
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Rick, There is no way to access the top of the frig without removing the whole thing from the trailer. I can't even see the top very well when viewed form the bottom with a flash light. Like I said earlier, I was not having much of a problem anyway and the little fan improved the performace noticably. If i were you, I'd try a fan. They are cheap and easy to install.
Best wishes,
__________________
James Schmidt
29 ft Excello 1000
97 Expedition/Hensley Hitch/
McKesh mirrors
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