Refrig Fan Concern - Fiberglass RV


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Old 08-24-2017, 10:54 AM   #1
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Name: Dick
Trailer: '15 17' LD Casita and '17 Tahoe LT
Texas
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Refrig Fan Concern

I have a 2015 17' LD Casita. we recently purchased. The fan (factory Rodale) mounted on the coils was not coming on so I removed it and it was defective. Had problems finding the specs. on it but found that it turns at 3100 rpm and the CFM was 105. Had difficulty finding one that met those specs. as well as the 120x120x38 mm dimensions. Without going to Dometic, I replaced it with one from Fry's Electronics. Seems like most computer fans are 25mm thick instead of 38 or 40s. Bought one that has 3 speeds that can be reset manually for 3 different speeds and volume. On the bench, it sounded fine but once I installed it, it seems pretty noisy. Not bad, but noisy. Ran it last night on the speed and volume similar to the Rodale. Without the fan running, the refrig was reading 150 degrees at the coil thermistor. This morning the thermistor was reading 90 degrees and fan running. Without the fan yesterday, the freezer temp was showing 0 degrees and the self temp was 37 degrees. After running all night, the freezer is reading about 8 degrees but the self them is still at 37/38 degrees. Can you move to much air over the coils? The setting I used was 2500 rpm/115 cfm. Other than the drop in rpm and slightly more cfm, the only difference that might make a difference is it has 9 blades instead of the 5 blade oem. I think that accounts for being noisy. But I have never heard a stock fan run so I do not know how quiet they are. Any responses appreciated.
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Old 08-24-2017, 01:21 PM   #2
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Name: Steve
Trailer: Scamp 13
California
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Your fridge is controlling the fridge temperature not the freezer temperature. It only runs enough to maintain that temperature in the fridge. During the day its feeding more cold energy into the freezer more often to maintain the proper temperature in the fridge. Over night there is much less load on the fridge due to the ambient air temperature drop so the fridge runs less but still keeps the fridge at proper temperature. The fridge running less allows the freezer temperature to rise a little while maintaining proper fridge temperature. The cooling system first goes through the Freezer and the freezer trickles the cold air down into the fridge box through its heat sink fins. On my fridge I mounted an external computer fan to the heat coils and then routed the power to the fan through a thermal switch. That way at night when the outside temperature drops the fan automatically shuts off. We camp in the desert allot and during the cooler part of the summer and spring we would get 60 degree temperature swings. The fridge was unable to control these situations and typically try to freeze the fridge contents in the early mornings. Your fridge is much more controlling with logic circuits and such than my 31 year old basic camper fridge. If it came with a factory fan on the coils they may already be controlling the fan and could also be controlling the fan speed too.
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Old 08-24-2017, 03:24 PM   #3
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Name: Dick
Trailer: '15 17' LD Casita and '17 Tahoe LT
Texas
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Thanks Steve. When I bought the computer fan, the salesman said it was variable speed and controlled by the computer. When I opened it I found it has 3 switch settings. 1500 rpm, 2500 rpm and 3500 rpm. The colums vary from 72 cfm,115 cfm and 154 cfm. I ran it overnight on 1500/115. Seems to work fine but just wish it was a little quieter. The amp ratings are .25/.60/1.3.
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Old 08-25-2017, 06:56 PM   #4
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Name: Jann
Trailer: Casita
Colorado
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Originally Posted by dmad1 View Post
I have a 2015 17' LD Casita. we recently purchased. The fan (factory Rodale) mounted on the coils was not coming on so I removed it and it was defective. Had problems finding the specs. on it but found that it turns at 3100 rpm and the CFM was 105. Had difficulty finding one that met those specs. as well as the 120x120x38 mm dimensions. Without going to Dometic, I replaced it with one from Fry's Electronics. Seems like most computer fans are 25mm thick instead of 38 or 40s. Bought one that has 3 speeds that can be reset manually for 3 different speeds and volume. On the bench, it sounded fine but once I installed it, it seems pretty noisy. Not bad, but noisy. Ran it last night on the speed and volume similar to the Rodale. Without the fan running, the refrig was reading 150 degrees at the coil thermistor. This morning the thermistor was reading 90 degrees and fan running. Without the fan yesterday, the freezer temp was showing 0 degrees and the self temp was 37 degrees. After running all night, the freezer is reading about 8 degrees but the self them is still at 37/38 degrees. Can you move to much air over the coils? The setting I used was 2500 rpm/115 cfm. Other than the drop in rpm and slightly more cfm, the only difference that might make a difference is it has 9 blades instead of the 5 blade oem. I think that accounts for being noisy. But I have never heard a stock fan run so I do not know how quiet they are. Any responses appreciated.
Is the fan from Casita? I've never heard of any manufacturer putting a fan on the coils. Maybe it is an add on by the previous owner.
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Old 08-25-2017, 07:15 PM   #5
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Trailer: Escape 21 & Jeep GC 5.7 (Previous 2012 Casita FD17 & 2010 Audi Q5)
Puget Sound, WA
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The factory fan on our 2012 Casita could be distinguished by two snap-caps on the outside of the trailer shell between the two refrigerator wall-vents. It's mounted to a piece of wood that's mounted on the shell. I found that the factory fan tends to resonate on the shell and make a bit more noise than I'd prefer. It seems you could probably get some soft rubber worked into the mounting arrangement to dampen the vibration a bit.
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Old 08-25-2017, 07:38 PM   #6
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Name: Dick
Trailer: '15 17' LD Casita and '17 Tahoe LT
Texas
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The old fan was an OEM by Rodale from Casita and mounted with the two rivets, etc. As I mentioned, the new fan I installed was noisy. I took it out today and installed a different brand, but it only moves 40 cfm but you can not hear it running. It does run at 1000 rpm vs. the 1500 rpm I had the other one set on. It is moving the air, just not as much as before. I have it running in the drive way and will let it run for several days and keep checking the temps. So far today, the freezer and inside temp has remained the same with both fans. Maybe I can get a refund or exchange on the noisy one.
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Old 08-25-2017, 10:14 PM   #7
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Name: Jann
Trailer: Casita
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Originally Posted by Civilguy View Post
The factory fan on our 2012 Casita could be distinguished by two snap-caps on the outside of the trailer shell between the two refrigerator wall-vents. It's mounted to a piece of wood that's mounted on the shell. I found that the factory fan tends to resonate on the shell and make a bit more noise than I'd prefer. It seems you could probably get some soft rubber worked into the mounting arrangement to dampen the vibration a bit.
When did Casita start putting fans in the back of the fridge to cool the coils? How are they wired in and are they 12V or 110V? When in real hot weather the fridge struggles to keep it cold as I want it. If 12V how much power does it pull out of the battery?
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