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Auxiliary fridge fans for Dometic 8CF fridge

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  • Auxiliary fridge fans for Dometic 8CF fridge

    After my trip to Georgia and traveling in the high 90"s the fridge would not stay cool on propane. Once camped for the evening the fridge work fine, but I had to set it to max, both on propane and 120 to get it to cool down enough for the next days run. I believe adding additional cooling fans is my solution. I have not tried using my inverter to run it, but plan on a test to see how long the batterys can last witheh solar backup.

    So I have started a new project and I am at the planning stages. After reading a whole bunch of threads I have a corundum. Do I mount the fans on the top vent and push/blow air out, or on the bottom vent and push/pull air in. Right now I am thinking the former as this air flow would be directly across the top cooling fins.

    I have the single door 8 CF Dometic fridge in the slide. I contacted Dometic and they indicated I had a venting issue, but everything is in place (top baffle) per thier instructions. Everything is sealed correctly, but I could put add curved metal piece at the top to better direct airflow out the top vent. Ill try and get a few pictures tomorrow.
    MFG # 958687054
    SR# 73698-497
    MOD# DM2682RBFX
    All information came from label inside lower compartment

    Fans?????? This is where things get confusing. From the various threads the brands/sizes are all over the place. As this will be against the vent, I think I need IP68 rating. I will also need a water tight disconnect plug. Also almost every add for the fans does not specify an air flow rating. What CFM am I looking for 60 CFM or 110CFM? Or am I even in the ball park. My plan is to get two fans sized to fit the baffled opening. I will measure this tomorrow.

    The fridge has 1 existing fan, but for the life of me I cant figure out how to get to it (without pulling the fridge) Its in the middle between the two vents. I also want to wire the new fans into the same circuit if possible. but have never seen a wiring diagram how to do it. Will I need a relay, or is the factory board capable of handling the extra load of two fans? Or should I get a temperature sensor to run them and attach near the top fins. What sensor specifications do I need?

    Thanks for any thoughts on this.

    Keith
    2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

  • #2
    Keith

    Pulling the fridge is fairly easy, 2 screws on the bottom in the back and 2 on the front at the top, maybe on the bottom front as well, you will have to open the doors to see where they are in the front. Air movement over the coils in the back are a huge problem with a fridge in the slide. The air has to be forced down and out the vent. What I did on my Dometic was lift the metal deflector that lays on top of the fridge and add insulation to take up the large air space on top of the fridge, this is a good collection space for the hot air that you are trying to get rid of. I was going to make a metal deflector that would direct the air down and out the top vent but I moved on to a 12 v dc compressor fridge. The single small fan on the back of the fridge does little to move the air and more fans would help. There have been a few mods done which I am sure you have read already.

    Brian
    Brian & Michelle
    2018 Reflection 29RS
    2022 Chevy 3500HD

    Comment


    • #3
      At the top blow air out is most efficient. Mine are mounted right at the cooling fins so there is decent air velocity across them.
      I use two of these:
      https://www.amazon.com/Enermax-Mamga...00DNKU0S6?th=1
      Selectable speeds, very quiet. On my previous fifth wheel they lasted about 5 years before needing replacement. I thought that was pretty good for a $12 fan.
      I had one that I would turn on or off manually, the other I wired to an attic fan temp controller. They are cheap and you can select what temperature the fan comes on at, and, imo, much more reliable than those little on/off temp 'buttons' you see screwed to your cooling fins.
      I never needed to pull a fridge to add fans. Just worked form the top access door. On the 303 I had to modify the baffle to be removable, but still a lot less work than pulling the fridge.
      As Brian said, pulling the fridge isn't too bad, I just prefer to do it a different way.
      If you do remove the fridge, remember to undo the gas line and the 12vdc as well. Take a pic with your phone so you put the 12v wires back in the same spot. The 120 is a plug in cord and may be long enough to leave alone.


      2018 Dodge 3500 6.7 Cummins w Aisin and 9 cup holders
      Not to brag or anything about my finances, but my bank calls me about every day to tell me my balance is OUTSTANDING!

      Comment


      • #4
        Thanks folks Questions on fans - 2 pin (red black I understand) 3 pin is the 3rd wire for temp sensor to turn on or what? Noise DB - it appears I need to stay below 20 - 25 DB some of the higher flow ones ar up to 45 DB which I know would be loud.
        Scott Scott'n'Wendy I cant tell if the fan you recommend has ball bearings. I was looking at a slightly tilted install to get better airflow through the grate. I know a sleeve bearing is not what I want.

        Thanks
        Keith
        2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

        Comment


        • #5
          I just ran across theses two IP67 rated fans.

          This would solve my concern of attaching then to the vent grate or very near the grate to the top of the vent door frame.
          https://www.amazon.com/dp/B00KFCR0PQ/ref=emc_b_5_t
          or
          https://www.amazon.com/Noctua-NF-F12...ef_=ast_sto_dp
          and a manual controller
          https://www.amazon.com/Noctua-NA-FC1..._dp&th=1&psc=1

          From the wiring diagram it appears the power connection could be trimmed (remove computer power supply end) and tied into the RV 12V with a fuse. It comes with a harness that could run both fans. or even up to 3.
          https://noctua.at/pub/media/blfa_fil..._manual_en.pdf

          I sent an email off to them asking if it would work and it they have extension cables for the fan leads.
          I am now thinking I like the idea of full manual control as I can turn them off if as needed. Sound is right at 31db db max speed. Only do that while traveling.

          Thoughts?
          2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

          Comment


          • #6
            Yoda

            Short version, Cold Air comes in the bottom, Hot air rises and exhausts at the top.

            Best results with fans blowing hot air OUT.

            Bonus point to create a baffle that forces air onto the fins, and forces it out the top vent.

            Not my diagram, but you get the point. (This person was trying to improve the insulation value of there camper to reduce the amount of heating required.

            Click image for larger version

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            Mike
            2017 Imagine 2800BH pushing a 2019 Ford F150 Platinum

            Formerly: 2002 Rockwood Popup
            Location: Massachusetts

            Comment


            • #7
              Originally posted by mpking View Post
              Yoda

              Short version, Cold Air comes in the bottom, Hot air rises and exhausts at the top.

              Best results with fans blowing hot air OUT.

              Bonus point to create a baffle that forces air onto the fins, and forces it out the top vent.

              Not my diagram, but you get the point. (This person was trying to improve the insulation value of there camper to reduce the amount of heating required.

              Click image for larger version

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              Thanks Mike but my fridge vents out the side, not the top. Fridge is located in a slide so I have a second vent in wall at top of fridge.
              Thanks for the information.

              Safe travels


              2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

              Comment


              • #8
                Originally posted by Yoda View Post

                Thanks Mike but my fridge vents out the side, not the top. Fridge is located in a slide so I have a second vent in wall at top of fridge.
                Thanks for the information.

                Safe travels

                We got pictures for that too.... :-) This one has two fans in the picture (not nessacary)

                Click image for larger version

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                Mike
                2017 Imagine 2800BH pushing a 2019 Ford F150 Platinum

                Formerly: 2002 Rockwood Popup
                Location: Massachusetts

                Comment


                • #9
                  Originally posted by Yoda View Post
                  Thanks folks Questions on fans - 2 pin (red black I understand) 3 pin is the 3rd wire for temp sensor to turn on or what? Noise DB - it appears I need to stay below 20 - 25 DB some of the higher flow ones ar up to 45 DB which I know would be loud.
                  Scott Scott'n'Wendy I cant tell if the fan you recommend has ball bearings. I was looking at a slightly tilted install to get better airflow through the grate. I know a sleeve bearing is not what I want.

                  Thanks
                  Keith
                  Tilting will not get you any appreciable increased air flow. The fans I like are 20db. Doubt they are ball bearings because they would be noisy and these fans are very quiet.
                  2018 Dodge 3500 6.7 Cummins w Aisin and 9 cup holders
                  Not to brag or anything about my finances, but my bank calls me about every day to tell me my balance is OUTSTANDING!

                  Comment


                  • #10
                    Originally posted by mpking View Post

                    We got pictures for that too.... :-) This one has two fans in the picture (not nessacary)

                    Click image for larger version

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                    Mike - Bingo - that's the setup up I have. I am considering two fans up top only, I do need to fab up the top baffle shown. I also need to check for the intermediate baffle too.
                    Thanks for the help.
                    Keith
                    2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                    Comment


                    • #11
                      Originally posted by Scott'n'Wendy View Post

                      Tilting will not get you any appreciable increased air flow. The fans I like are 20db. Doubt they are ball bearings because they would be noisy and these fans are very quiet.
                      Thanks Scott - I will take a second hard look at your fans. How did you wire them in if I may ask?

                      Keith
                      2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                      Comment


                      • #12
                        Yoda
                        Not sure what you are after exactly on how I wired them.
                        But here goes.
                        There is 12vdc connected to the fridge module. I cut that wire and spliced into it. I fused each fan at one amp. I used Weidmuller ASK-1 fused terminal blocks. I did not want a failed fan to take out the whole fridge. At this point, on our 303, it has the original fans operating as factory intended. With the two extra fans, I can close one or two fused terminal blocks to increase air flow depending on how the fridge is operating. ie..if the fridge internal temp is creeping up, I add a fan. The fused blocks are at the bottom right of the lower fridge access panel.
                        2018 Dodge 3500 6.7 Cummins w Aisin and 9 cup holders
                        Not to brag or anything about my finances, but my bank calls me about every day to tell me my balance is OUTSTANDING!

                        Comment


                        • #13
                          Originally posted by Scott'n'Wendy View Post
                          Yoda
                          Not sure what you are after exactly on how I wired them.
                          But here goes.
                          There is 12vdc connected to the fridge module. I cut that wire and spliced into it. I fused each fan at one amp. I used Weidmuller ASK-1 fused terminal blocks. I did not want a failed fan to take out the whole fridge. At this point, on our 303, it has the original fans operating as factory intended. With the two extra fans, I can close one or two fused terminal blocks to increase air flow depending on how the fridge is operating. ie..if the fridge internal temp is creeping up, I add a fan. The fused blocks are at the bottom right of the lower fridge access panel.
                          Thanks I think I follow. The important thing is you wired them in for manual operation, and not auto - attached to the stock fans.

                          Keith
                          2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                          Comment


                          • #14
                            Did a bit of research today on the existing fridge fan. Unfortunately I can get to it to read the number but based on the part number found here https://www.edometic.com/allusr/sp.n...y=C7ZTXBA-NNMU
                            The fan part number is 38511830166 this refers to an ADDA brand AD0912UB - A71GP. I can't find an exact match on thier site but it appears to be about 52 CFM and is a 92x92x25 mm fan.
                            Can anyone verify this?

                            Thanks
                            Keith
                            Last edited by Yoda; 10-21-2021, 08:33 PM.
                            2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                            Comment


                            • #15
                              Keith

                              Here is a picture of my fan.
                              Click image for larger version

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                              According to the numbers they match.

                              Brian
                              Brian & Michelle
                              2018 Reflection 29RS
                              2022 Chevy 3500HD

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