My attempt at adding fans to back of fridge compartment.

[RxGuy]

Built this 2 fan add-on for our 2010 International 27FB.

We were having the same problems as a lot of owners on, on a very hot day, fridge struggles to keep the food compartment cold.

Toggle switch is an ON-OFF-ON. I used the channel aluminum because I had it. 1 amp inline fuse. 12v ball bearing 36cfm @12v

I plan on using snap disc thermostat on at 100F off at 85F.

The on-off-on configuration is so I can bypass the thermostat if I want to.

Hopefully it will do the trick

[SuperTrouper]

Looks good to me! Here's a thread that that has a lot of other designs but your image and control description seem to be very clean and effective. https://www.airforums.com/forums/f42...-211379-2.html

[RxGuy]

Thanks for the link Brad.

I will post pictures of the install when I am done.

The trailer is in storage now, it's about 35 miles from where we live. Probably get down there this week. (hopefully)

How important is the location of the thermostat? I'm thinking the closer I can mount it to the condenser and away from the burner the better. Plan is to mount (zip tie) it someplace.

[BigAl]

One thing that is not often mentioned is that the back of the fridge should only be about two inches from the outside wall of the compartment. Very easy in a square box trailer but not the Airstream with the curve in the wall. Mine is about 10 inches from the wall. To be really effective you should mount a sheet of aluminum to the tubing on the back of the fridge on standoff brackets and direct the airflow up between the fridge and sheet. My next project.

[RxGuy]

Originally Posted by BigAl

One thing that is not often mentioned is that the back of the fridge should only be about two inches from the outside wall of the compartment. Very easy in a square box trailer but not the Airstream with the curve in the wall. Mine is about 10 inches from the wall. To be really effective you should mount a sheet of aluminum to the tubing on the back of the fridge on standoff brackets and direct the airflow up between the fridge and sheet. My next project.

Good suggestion...thanks.

[ITSNO60]

Originally Posted by BigAl

One thing that is not often mentioned is that the back of the fridge should only be about two inches from the outside wall of the compartment. Very easy in a square box trailer but not the Airstream with the curve in the wall. Mine is about 10 inches from the wall. To be really effective you should mount a sheet of aluminum to the tubing on the back of the fridge on standoff brackets and direct the airflow up between the fridge and sheet. My next project.

It is my understanding the Norcold and Dometic both say less than 1". I accomplished that by pulling the fridge out and fastening foil backed rigid foam behind it to bring the gap down to 3/4" and the foam helps reduce the heat gain from the sun.

I will say that every mod I made had an incremental improvement but the one that had the biggest improvement was evaporator fans.

https://www.fridge-and-solar.net/fridge_vent.htm

[ITSNO60]

Originally Posted by RxGuy

How important is the location of the thermostat? I'm thinking the closer I can mount it to the condenser and away from the burner the better. Plan is to mount (zip tie) it someplace.

My Dometic came with a condenser fan and they placed the snap disc on the coil near the top, see pics. They also didn't vent the flue to the outside and the hot flue gasses were pouring out right onto the condenser which may be why they put a fan there, to band aid their poor installation. My flue is now wrapped in Kaowool and vented to the exterior and I upgraded to 2 ball bearing fans controlled by the snap disc. Sorry that second pic won't rotate for me.

[Al and Missy]

Another thing to look for. The installation manual for my Dometic says there should be no more than 1" air space on the sides and top of the unit. My 2002 trailer has a vent in the roof over the back of the fridge to allow heat to escape by convection and was not originally equipped with a fan.


The replacement cooling unit I had installed said to preserve the warranty a fan should be installed. The installer put the fan under the condenser tubes blowing up toward the vent. There is an air space over the freezer that is several inches in height. I believe the fan is pushing the hot air up into that space and degrading the performance of the freezer.

[SuperTrouper]

Originally Posted by RxGuy

How important is the location of the thermostat? I'm thinking the closer I can mount it to the condenser and away from the burner the better. Plan is to mount (zip tie) it someplace.

Hi RxGuy,

If you look at my fan install post you can see in one of the pictures that I mounted the temp sensor stuck through a hole in the wood panel above the second section of boiler tube return. It seems to work well. In really hot areas, I prop open the fridge door while parked to help with ventilation as well.

https://www.airforums.com/forums/f42...ml#post2386494

[RxGuy]

Got it installed today. Won't be able to test it out for a while.

[MMCMRET]

Following.

[ETroup]

This is what I did to improve the refrigerator cooling performance. This model AS has one low sidewall louvered vent opening and then a roof vent. I noticed the interior side walls get pretty warm inside the Airstream around the refrigerator. Seems as though the roof vent does not release enough of the heat via natural convection. Would like to pull the refrigerator out and see if there is an obstruction but have not got around to that yet.

I used a couple of 12VDC computer fans and custom built a shroud out of aluminum sheet metal I bought at Home Depot to mount the fans and hold them in place. I just turn them on when on shore power and it is warm outside. Seem to work well both on propane and electric modes.

[RxGuy]

Originally Posted by ETroup

This is what I did to improve the refrigerator cooling performance. This model AS has one low sidewall louvered vent opening and then a roof vent. I noticed the interior side walls get pretty warm inside the Airstream around the refrigerator. Seems as though the roof vent does not release enough of the heat via natural convection. Would like to pull the refrigerator out and see if there is an obstruction but have not got around to that yet.

I used a couple of 12VDC computer fans and custom built a shroud out of aluminum sheet metal I bought at Home Depot to mount the fans and hold them in place. I just turn them on when on shore power and it is warm outside. Seem to work well both on propane and electric modes.

Attachment 441820
Attachment 441819

Very Nice!!! Clean and simple.

[BJnewby33]

Recently I had to replace my original Dometic with another Dometic frig. It stays so cold that I basically have (almost) two freezers. I've followed the directions and no matter what I do, it's still just a hair above freezing. Thanks for any suggestions here? Barbara

[1970 Safari]

WOW! I wish I had that problem. Can hardly keep bags of ice frozen in the freezer..... Have you checked the location (is it attached?) of the temp prob that is attached to the cooling fins inside the refer portion of the unit? Sliding it up and down the fin can(?) affect the temperature.

I have done the fans, prop open the hatch, scold my wife to keep the door closed
(Only 1 time!! ) with not much change to the cooling. Keeping the freezer (and refer sometimes) full of bagged ice as the contents diminish does help some.

I like the use of foil faced insulation on the wall to fill the gap, I never knew about the clearance..

Maybe I will not need to convert to 12VDC fridge! smile

[Jeb-TN]

If you do any off grid camping be sure your fans don't pull to much power. I added fans to a slide in camper frig I use to have and when looking for fans I saw a big difference between different fans. You want to compare the CFM of the fan versus wattage. It can vary by almost a factor of 2. If I remember right I found two that put out more air at less power than one bigger one.

[B17drvr]

Try the JC refrigeration mod.

[ITSNO60]

Originally Posted by BJnewby33

Recently I had to replace my original Dometic with another Dometic frig. It stays so cold that I basically have (almost) two freezers. I've followed the directions and no matter what I do, it's still just a hair above freezing. Thanks for any suggestions here? Barbara

I see you are in South Dakota which may have something to do with it! First thing I would try is a small circulating fan inside the fridge to see if it evens the temps out.

[duboismjjp]

Would you have a pic on how you vented your flue outside, presumably through the sidewall vent door? Thanks

[Aironius]

Good move. Those absorption refrigerators are designed to have a roof top exhaust vent to encourage convective air flow. AS uses 2 side vents, which is not as effective. Heat is trapped in the cabinet.
I added 2 fans in my Bambi. No pics right now due to losing them in a HDD crash, but one fan blowing hot air out thru the top louvres and 1 fan blowing cool air upward inside the cabinet. The temp switch needs to be mounted on the finned pipe at the top of the unit. I drilled 2 holes in the cooling fin on the pipe at the top and attached it there so it actually senses the temp of the fluid in the system. Works good, cycles on and off in hot weather. Doesn't work when the main power switch is off, but when on the road the draft does the job.