SJ-Chris
San Jose, Ca
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I have 3 RVs and I seem to be addicted to adding stuff to them....lol.
They each have a standard Dometic 2852 absorption refrigerator. They seem to be working as expected. I did replace the cooling unit on one about 2 years ago and it has been working flawlessly.
My question is this... Under NORMAL OPERATION how hot does it get behind the refrigerator in the cabinet area and venting area out through the roof? And does adding a fan back there do much of anything to help with refrigerator operation (keeping interior of the refrigerator/freezer cool)? I'm not talking about preventing overheating and/or fires...just wondering if it helps the refrigerators perform better.
Something like this with some sort of thermostat such that it's not running all the time:
![[image]](https://i.imgur.com/DE8VnM8l.jpg)
This particular fan moves ~38CFM at 45dB (might be louder than I'd like, but behind a refrigerator would probably muffle the noise quite a bit). Maybe I could find something quieter...
Here is a nice but simple 12v thermostat that could be programmed to turn the fan "on" when it hits a certain temperature and then turn it "off" once the fan cools it down to some lower value.
https://www.mpja.com/Single-Zone-Intelligent-Thermostat-Temperature-Controller/productinfo/34757+MP/
Let me know what you think. Total waste? Or significant increase in summertime cooling inside your fridge? I sometimes camp or lend out my RVs in 100+ degree summer temps.
Does anyone have any "before and after" data points or personal observations after having added such a fan?
Thanks!
Chris
* This post was
edited 10/20/22 07:33pm by SJ-Chris *
San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs
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Fisherman
Angus, Ontario, Canada
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I'm not in the same temperature zone as you are but without a doubt adding a 4 inch fan at the upper vent made a fair bit of difference. It was a 3 speed fan and I was lucky enough to have 2 unused spade terminals on the back of the fridge made for this, on all but the hottest days I had it on the lowest speed, 90+F days I upped it to med or high as required and wouldn't believe the heat coming out of the vent. It definitely dropped the interior fridge temps and sped up the cooling process by about 1/2 the time. I don't know what the dB rating was but I could barely hear it at night during quiet times. I don't know what the brand name was, just 12DV DC with a 3 speed switch.
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RLS7201
Beautyful Downtown Gladstone, MO
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I have a Dometic 2708 in my old Bounder. I find that a small 4" box fan helps when the ambient temperatures get above 85°F........I tie wrapped the fan on the large tubes on the bottom of the unit.
One observation that I've made is the RV manufacturers don't follow the the instillation instructions. There should be NO air flow on the sides and the rear should be with in 3/4" of the wall. I've helped several friends by blocking the sides and baffling the rear.
Fortunately for me, Fleetwood used to get it right.
Richard
95 Bounder 32H F53
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toedtoes
California
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My motorhome never needed it. The heat easily rose up the vent and out. The fridge never had reduced cooling even in high temps.
With my trailer, it is vented out the side. The fridge cooling capabilities are significantly reduced in high temps. The fans are absolutely required - I also put a reflective window sheet on the wall below the vent to reduce the external heat.
If you have a significant difference in the fridge's cooling capabilities depending on external temps, then adding the fan may help. If there is no difference, then the fan is unnecessary.
1975 American Clipper RV with Dodge 360 (photo in profile)
1998 American Clipper Fold n Roll Folding Trailer
Both born in Morgan Hill, CA to Irv Perch (Daddy of the Aristocrat trailers)
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Tvov
CT
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Our frig always seems to work better when the daytime temperatures are hotter. My wife has mentioned that too, so I don't think it is just me imagining it. Our TT frig has side and roof vents, so I assume the hot air vents itself out.
I am not sure an exterior cooling fan would make much of a difference.
What I have heard a lot of people do is put a fan inside the frig to help even out the cooling.
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2021 F150 2.7
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enblethen
Moses Lake, WA
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I would check for clearance between outside wall of rig and the cooling fins. It should be less than an inch. By reducing the clearance as indicated in installation manual more air would move through the cooling unit coils increasing the efficiency.
Bud
USAF Retired
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pianotuna
Regina, SK, Canada
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SJ-Chris wrote:Does anyone have any "before and after" data points or personal observations after having added such a fan?
Thanks!
Chris
Yes.
Cool down from ambient without fans 4.5 hours to first cycle
Cool down from ambient with fans 3 hours to first cycle.
My twin computer fans are in a mask at the top of the chimney. They are thermostatically controlled.
This limits air flow in colder weather.
I do have a thermocube and a 40 watt bulb for freezing temperatures.
* This post was
edited 10/21/22 12:15pm by pianotuna *
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.
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Lwiddis
Southern California :(
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An interior fan is all I’ve needed.
Winnebago 2101DS TT & 2022 Chevy Silverado 1500 LTZ Z71, WindyNation 300 watt solar-Lossigy 200 AH Lithium battery. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist. 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad
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SJ-Chris
San Jose, Ca
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Fisherman wrote:I'm not in the same temperature zone as you are but without a doubt adding a 4 inch fan at the upper vent made a fair bit of difference. It was a 3 speed fan and I was lucky enough to have 2 unused spade terminals on the back of the fridge made for this, on all but the hottest days I had it on the lowest speed, 90+F days I upped it to med or high as required and wouldn't believe the heat coming out of the vent. It definitely dropped the interior fridge temps and sped up the cooling process by about 1/2 the time. I don't know what the dB rating was but I could barely hear it at night during quiet times. I don't know what the brand name was, just 12DV DC with a 3 speed switch.
Cooling in 1/2 the time seems very worthwhile. Thanks for the data point!
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SJ-Chris
San Jose, Ca
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pianotuna wrote:SJ-Chris wrote:Does anyone have any "before and after" data points or personal observations after having added such a fan?
Thanks!
Chris
Yes.
Cool down from ambient without fans 4.5 hours to first cycle
Cool down from ambient with fans 3 hours to first cycle.
My twin computer fans are in a mask at the top of the chimney. They are thermostatically controlled.
This limits air flow in colder weather.
I do have a thermocube and a 40 watt bulb for freezing temperatures.
Cools 33% faster....excellent data point!
Question: What does "in a mask" mean? Thanks!
-Chris
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