Muffin Fan Installation Norcold 1200LRIM

[Executive45]

It is imperative that the cooling units on the Norcold 1200LRIM get proper ventilation. These units are shipped with two muffin fans mounted on top of the coils. Drawing air upward over the coils is more efficient than blowing air upward from the bottom. The problem arises when outside temps skyrocket. The coils heat up and the cooling process diminishes. Often, the OEM muffin fans are inadequate to keep up or they fail altogether. To access these fans, the fridge must be pulled part way out and even then it's a pain. My solution to these issues was to buy and mount additional fans and put them where I could easily access them if they were to fail. My two OEM fans pulled 45cfm ea.

I purchased four of THESE fans @ $4.25ea. I also purchased a new snap switch to control the fans although they really could run 24/7. These button switches are available on Ebay, package of three for $5.15 free shipping. Finally, I purchased two 48" pieces of 3/4 angle aluminum stock from Home Depot at $6.15 ea. Mounting screws are a personal choice, but I chose 2" stainless steel hex screws with nylon lock nuts. Package of two @ 98 cents/ea.

Below are some pictures to assist if you decide to follow my footsteps. It took me about 1 1/2 hours the first time and about an hour the second time. Originally I mounted the fans flush with the roof line but the hum resonated through the coach so I disassembled everything and redid it lowering the fans further into the flue opening.....PM me if you have any questions. Hope this helps someone....Dennis


Up on the roof, this is what you see.

After removing the shroud, there is a plastic mesh covering

Remove the plastic mesh covering

I removed the fans I had installed a few weeks ago

Using scrap left over from making the fan holder, I made 4 legs

Remounting the fans using the new legs prevents the sound from resonating in the coach

The beige plastic cover you see in the pictures is for my solar panels. The wiring runs down the side of the refrigerator compartment. I used this wiring loom to run my 12VDC wiring for the muffin fans. I now leave my fridge on 3 and keep the box temp around 38 degrees and the freezer below zero. In 100+ outside temps I kicked it up to 5. IMHO, this is a simple, inexpensive way to enhance the performance of your Norcold. Also, if I have any problems with these fans, they are readily accessible......Dennis

[Daveinet]

I am a little confused about something. I remember the fridge my parents had in their second motorhome. OK, we live in the midwest, but that fridge would freeze the refrigerator, if you set it cold enough. It did not have any fans. I do remember traveling to Florida once, and the fridge was still not a problem. Why do fridges now need fans, when they never needed them before? The Dometic in my coach cooled very well, and did not need a fan when it was new. It was only after I replaced the cooling unit, that it was marginal in hot weather. I have since replaced the cooling unit again with one of the "Amish" units. It also does NOT cool as well as the OEM unit, although seems to be better than the previous unit. Seems if these cooling units were built right, they would not need fans. Yes, I am considering putting a fan on my current unit, but I would rather it just worked as well as OEM.

[Executive45]

Thanks for your input. I spoke with D. Force from Pine RV, makers of the Amish unit. He says the design is great. According to him, the fans are necessary for the fridge to work properly. If the fans fail, your fridge is not going to cool anyway, so impediment is not a problem. I still have the two nonop fans down in the bowels behind the fridge and they don't seem to be a problem. Besides, by dropping the fan assembly down into the flue opening, there is about 4 1/2" around the entire assembly.....Dennis

[Mainship]

One modification I would like to do, but seeing the completed setup I agree with Rick, natural flow would be impeded. I put a fantastic fan in the bathroom replacing the small fan located in the corner of the original, what I found is a lot of wind turbulence, on low it works fine, high speed and it blows back as I have a max vent over the top. Maybe two fans with directing panels above to prevent back flow.

[Rick_Jay]

Hi Dennis,

Nice work & nice pictures. I've been toying with doing something similar "one of these days". A few years back, our refrigerator seemed to be struggling to keep things cold, so I rigged up a muffin fan on the bottom blowing upward. That seemed to help. It ran all summer, then I disconnected it in the Fall. The next year (and ever since) the refer seems to work fine without it, so I have not really thought much about making a permanent solution. But most of our camping is done here in the Northeast part of the country, so the temps are a bit more moderate than folks experience down south. 🙂

I do have one concern with your design, but might not be a big deal. I was wondering how those fans effect the cooling operation of the refer if they aren't running. For instance, suppose there is a failure somewhere and the fans aren't drawing air up the coils. I'm just wondering if the stationary fan blades would impede the normal passive air flow and cause other problems with the cooling unit. If that's the case, then maybe using just 2 fans might be better as there would be better airflow if the fans weren't running?

Probably a non-issue, I guess it's just my suspicious nature of relying too heavily on $16.00 worth of Chinese made fans! LOL

Thanks for the post.

~Rick

[bob213]

Where does that wire running out of the cover go to? Where do you pick up you 12V DC? That's got to be a great improvement in air flow! Nice job.

[Executive45]

Dave, their amp draw is so minimal that running all four 24/7 won't make much difference. Yes, it's probably overkill but, if two are good, four must be better, right?...:B...actually, I originally wanted to take up all the room from the flue to have a better draw up through the opening. These fans, for the price, were the best I could find....and, they are quieter than the small two fan one that clips to the fins, I put inside three years ago....Dennis

[Daveinet]

Looks like a good source for fans, especially since these are ball bearing, rather than sleeve bearing like most muffin fans. One thing I do wonder about and that is at 100 CFM each, that seams like way over kill. Just a small amount of air flow over cooling fins makes a huge difference in heat transfer. In looking at the set up, makes me wonder if one would be wise to wire them in pairs of 2 in series. That would cut the load in half, and probably still have plenty of flow. I'd bet tempted to run all 4 in series, although I'd fear if they would actually all run. I suppose if you are in really hot areas, you could use switches to switch back and forth between series and parallel. Then worst case, you would always have enough, but could save on your batteries when boondocking.