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Open Roads Forum  >  Tech Issues

 > Slide out refrig struggles to cool tunnel cooling mod

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computermonkey

Oklahoma

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Posted: 06/04/19 08:27am Link  |  Quote  |  Print  |  Notify Moderator

This is my mod to the air flow tunnel of the refrigerator to help resolve bad cooling performance. To start out I'll give a little history. My wife and I purchased a 2016 Eagle Cap 960 in February of 2018. We drove 8hrs to get the camper. The high for the day was 24 degrees f. After looking everything over we were on the road. Temperatures for the whole weekend didn't break 30. Needless to say, the fridge didn't have to struggle very much. Fast forward to spring. Taking the camper out for the weekend we notice the fridge was having trouble getting down to 40 and the freezer getting under 30. After doing a little research I decided to get an ARP controller with fans. (https://www.arprv.com/) This did help a lot, but the high temps where in the 80's. A couple of months later we went on vacation heading West. Again, the fridge struggled while on the road. Temps reaching above 90. While we were parked, and the inside of the camper was in the low 70's the fridge worked fair just getting us by. The last day on the way home it gave up with temps inside reaching mid to high 40's. This all happened over two weeks.

With temperature starting to climb I think something needs to change. I’ve heard how bad refrigerators operated in slide outs. It was nice to know I'm the only one with this issue, but I didn’t see any real solution.

I wish I could say this was my idea, it's just my mod to my camper. I got this idea from a seeing a class A in a shop. I just modified it to fit my design. The heat/top outlet was partially blocked off by a piece of wood still leaving a gap between the cooling fins and the piece of wood to try to direct the air over the fins. I didn’t get a ladder to climb up to see the location of the fins. I went a step further, I used a piece of aluminum flashing (bought at Ace Hardware) to direct all of the air coming through the tunnel over the fins. The thickness of the wood can very. I used 1/8 thick and doubled it where the screws go into the wood. I used 1-inch wood dowels cut long enough to space the wood to the inner edge of the inside door. Your have to leave enough space between the wood and the door to allow air to exit in all of the vents. The flashing can be angled to best fit your install to fill and gap between the wall and top fins.

The DMR702 originally had one 80mmx80mm over the coils to move air up through the tunnel. I found two 140mmx140mm water resistant fans and wired them into the same circuit of the stock cooling fan. I then took used bike tubes cut to cover the hot coils and used zip ties to strap on the 140mm fans. I decided to move the two squirrel fans that I had purchased with the ARP controller to the bottom cover to force cool air into the compartment.

Used the ARP to monitor the boiler and the coil temperatures, and to turn on the squirrel fans when the lower second top reaches 130 F. I let the DMR702 run for a week on propane. Outside temps reached 91 and inside of the camper reached 99. The A/C was not ran. I had almost two gallons of water at temperature of over 80 degrees inside the fridge. I started the test in the afternoon when the temperature was at the highest. This day reached 80 degrees. By evening the freezer was down to 20 degrees. One day later the fridge reached 40 degrees. Watching the ARP and keeping note of the fridge performance, the boiler never reached over 189 C, and the coil temp didn’t reach over 130 F for the week. All of this was done on the lowest setting. Before the unit struggled at the highest setting.

Before the mod the boiler reached 213 C. Pretty high. No wonder it wasn't getting cold. The ARP was a great tool to help diagnose this problem and to show the efficiency of the mod.

https://imgur.com/a/0iujT0J


2013 RAM 3500 Crew Cab 4x4
2016 Eagle Cap 960
Old camper
2004 Jayco Talon ZX
1998 2500 Suburban with Cummins 6BT


CA Traveler

The Western States

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Posted: 06/04/19 09:03am Link  |  Quote  |  Print  |  Notify Moderator

Nice solution. I tested my slide out refer at 110F w/o A/C and it would not adequately cool. OK with the A/Cs on but it runs a lot.

I've just completed installing 2 fans on the plywood where you have the aluminum. With the vent attached the fans are adjacent. Tests show a lot of hot air expelled.

I have a inside switch for 1 fan, off, 2 fans and will be testing this setup this summer.

I plan to add a very high temp thermostat and a lower temp one to cycle the fans.


2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
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Bob


Old-Biscuit

Verde Valley

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Posted: 06/04/19 09:47am Link  |  Quote  |  Print  |  Notify Moderator

Both posts above have the same issue in common.........

LOUSY fridge installations by RV MFG.

RV Fridge NFGs have 'specific' installation instructions/manuals for each model.
Failure to follow those instructions can/does lead to poor cooling performance.
When that occurs the Fridge is blame


Is it time for your medication or mine?


2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
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computermonkey

Oklahoma

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Posted: 06/04/19 11:47am Link  |  Quote  |  Print  |  Notify Moderator

Without any deflector all most all of the air that goes through the tunnel exits before passing over the fins. Only nature heat/cold exchange moves the air. With the fins suck in the corner how do you except any air to move over them.

computermonkey

Oklahoma

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Joined: 07/20/2006

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Posted: 06/04/19 11:49am Link  |  Quote  |  Print  |  Notify Moderator

Old-Biscuit wrote:

Both posts above have the same issue in common.........

LOUSY fridge installations by RV MFG.

RV Fridge NFGs have 'specific' installation instructions/manuals for each model.
Failure to follow those instructions can/does lead to poor cooling performance.
When that occurs the Fridge is blame



I was actually looking at replacing this unit.

I think if it wasn't for the ARP monitoring the boiler this could have turned into a bad situation.

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