Norcold 2118 - Blowing 5A fuse - Block off at the top vent?

[Overtaxed]

I have a 2118 that's blowing the 5A fuse on the control board when the fans come on. It's not immediate like some others are, but I think it's the same problem. I pulled one (of the 3 on the back) of the fans off to see if that was the culprit, unfortunately, it wasn't, so I moved on to the 2 upper fans (which can be accessed from the top vent from the outside of the RV. When I opened that vent, I found something a little surprising, most of the vent area is blocked off by a sheet of 1/4" plywood, it's about 1/2 the vent area; there's a sheet of plywood that extends from one side to another and leaves just the "fins" at the top open to the vent.

So, 2 questions. First is "why"? Is there some reason that they did this; changing the flow of air to get better cooling? I can't see how this would be better than just having the entire area open, but, I'm not a HVAC engineer either, so, what do I know. The next question, how on earth do I get to the upper fans with this thing in the way?! I can touch them with my fingers, but no way I can get a tool in there to get them out of there; I'd need to cut the plywood out of the way to be able to get in there. I think glued and screwed, so I'm not sure there's a way to get it out intact, if I'm going to get it out of the way, it's not going back in because it'll take some time with a saw to get it out of there.

And, actually, a 3rd question; if this is normal, and it's supposed to/needs to be there, how on earth do you get the cooling fans out for inspection/replacement? I just can't see a way to do it without pulling the fridge out?!

https://www.youtube.com/watch?v=V0TOxC3yjDM

Guess the plywood is normal, @6:41 in this video you can see what I'm talking about, he has exactly the same thing. Man, is "pull the fridge" really the way to get at those fans?! Ugh, that sounds like "dealer job" to me.

[xrated]

First.....Yes, that panel at the top is supposed to be there. It helps direct the airflow up and across the upper coils. Removing it will definitely cause more issues as the air flow will simply go out the upper vent before going across the upper coil and providing the heat exchange from the coil.

The 5A fuse that you are referring to is a known issue with it blowing. Grand Design and Norcold I believe has OKed replacing it with a 7.5 Amp fuse. There have been lots of discussions about the Norcold 2118 and it's problems, the 5A fuse and the cooling fans being one of them. Many folks, myself included have added additional fans in the top vent area......even if the existing OEM fans are still running and operating as designed. The more air flow you can get across that upper heat exchanger, the more likely the fridge will operate at higher ambient outside temperatures.

I installed a Titan brand twin cooling fan kit to the inside of the upper vent cover. I'll post a link to the one I bought, but basically, the first thing I would do is to check and make sure that the smaller lower fan is running when it is suppose to be, and also that both of the upper fans are running when they should be. If they are, and the 5A fuse is still blowing, replace it with the 7.5 Amp fuse and see if they keep running and not blow the fuse. If you are still having issues with the fridge not cooling the fresh food section down enough in high outside temperatures, it is time to do some investigation as to the cause.
1. Door flap.....make sure it is working correctly.......a known issue
2. Thermistor inside the fridge. It should be on the second fin from the right, as you are looking at it with the right door open. The top of the clip that holds it in place should be 3/8" to 1/2" from the top of the fins.
3. Consider additional fans for the rear compartment to move more air across the upper heat exchanger in the back.

Here's a link to the kit that I have installed. Results after the install were very good for cooling. I can provide more detail, but in a nutshell, fresh food section was at 28 degrees, and the freezer at 3 degrees .

Link:............. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Overtaxed]

Wow, that was some useful info, thank you xrated!

I was thinking about going to a 7.5A fuse, I did check, all fans are running, all appear smooth when they run or spun manually. And it's not the issue that some people are seeing of an immediate blowout, it takes some time for mine to go (10+ minutes); I suspect the fans are heating up, resistance rises, and eventually.. Pop. I'll give the 7.5A a try first.

I'm also looking at fans like you posted to increase the airflow back there. Did you wire that into the existing circuit that runs the fans or straight to the 12V line? I was actually thinking of taking all the external fans off the controller board and putting them direct to a fused 12V line; I'm not sure what running through the controller is buying me on the external fans, they have a thermostat already, so, why not just direct to a 12V line? That way I could add fans to that circuit which is already thermostatically controller without worrying about fuse issues.

I also have the door flap problem, but that's for a different day; I can deal with it, and I know how to close it "right", it just won't do it without a little coaxing.

Oh, one more question, I was thinking of doing a "push/pull" configuration, one fan on the top vent, one on the bottom (pushing air in). Think 2 on the top is a better configuration? I'm looking at the industrial !P67 rated Noctua fans, they are supposedly a little loud, but they move a LOT of air.

[xrated]

Wow, that was some useful info, thank you xrated!

I was thinking about going to a 7.5A fuse, I did check, all fans are running, all appear smooth when they run or spun manually. And it's not the issue that some people are seeing of an immediate blowout, it takes some time for mine to go (10+ minutes); I suspect the fans are heating up, resistance rises, and eventually.. Pop. I'll give the 7.5A a try first.

I'm also looking at fans like you posted to increase the airflow back there. Did you wire that into the existing circuit that runs the fans or straight to the 12V line? I was actually thinking of taking all the external fans off the controller board and putting them direct to a fused 12V line; I'm not sure what running through the controller is buying me on the external fans, they have a thermostat already, so, why not just direct to a 12V line? That way I could add fans to that circuit which is already thermostatically controller without worrying about fuse issues.

I also have the door flap problem, but that's for a different day; I can deal with it, and I know how to close it "right", it just won't do it without a little coaxing.

Oh, one more question, I was thinking of doing a "push/pull" configuration, one fan on the top vent, one on the bottom (pushing air in). Think 2 on the top is a better configuration? I'm looking at the industrial !P67 rated Noctua fans, they are supposedly a little loud, but they move a LOT of air.

In the rear compartment area of my 394M, there is a 12V source coming into that area. I tapped into that 12V source rather than using the 12V fan output of the Norcold circuit board. The reason for this is that the Titan fan kit comes with it's own controller and has a manual mode AND an automatic mode and six different speeds for the twin fans. It also comes with a temperature sensor that is used to control the fans when in auto mode. I have no intention of using the manual mode, and leave my fans turned off until ready to use it. I guess I forgot to mention the controller has a manual, auto, and Off choice. So the sensor goes in the back compartment area and actually starts the fans when in auto mode, at around 68 to 70 degrees back there (compartment ambient air temperature). If I'm remembering correctly, the thermostat on the Norcold itself does not start the fans until it gets to around 135 degrees and it's located on the upper heat exchanger cooling fins. In my opinion, 135 is too high for a start point, and secondly, with the thermostat being located on the cooling fins, almost at the edge of the fins.....the fans come on way too late to be efficient at keeping the heat exchanger doing it's job efficiently. I thought about just relocating the thermostat closer to the actual tubing so that it would come on sooner, but I also believe that the OEM fans don't move near enough air across the heat exchanger.....they are just not efficient and don't have enough CFM of air flow. By the time they kick on, the battle is lost on trying to cool the heat exchanger....if the outside air temperature is in the low to mid 90s. That is the primary reason I added more cooling capacity/air flow for the heat exchanger. This also points out just how critical that piece of fiber board or panelling is across the opening of the upper vent area.

Also, the door flap issue is VERY important to get resolved. When the flap doesn't completely close, it is the same exact thing as leaving the refrigerator door partially open....and the frig will never cool properly. I read somewhere, and I can't verify the accuracy of this statement, but someone stated that opening the door of the Norcold for 1 minute, the fridge will require running for 1 hour to make up for the loss of cool air that escaped when the door was open. So imagine if the flap is letting cool air out of there 24/7......the fridge simply doesn't have a chance to work properly....so it's a pretty big issue to get it closing correctly.

As far as a push/pull scenario, my feeling are that if the upper fans are trying pull out xxx CFM of air, that air has to come from somewhere. As long as there aren't any gaps or "holes" for the fans to pull are from, it has to come through the lower vent opening. So while you are working in the back compartment area, make sure that all the insulation on the sides and top of the fridge are in place and there is no areas for air to enter the compartment area other than the bottom vent opening. It there isn't, then I see no need for a push/pull type setup; the top fans (two 120mm fans with the Titan) should pull a sufficient amount of air in through the bottom opening, up across the heat exchanger, and out the top vent opening.......just make sure that the wood is kept intact across the upper opening....it does serve a vital purpose. Hope this helps

[Txfivver]

Overtaxed here is what the back of your fridge looks like if you've never seen one. You can see the two fans and the coils up top. The plywood piece is to direct the air up over the coils and out the vent. From the back the whole thing looks like
a high school science project, it's a wonder they work at all! And the worst part is it weighs 300 pounds! Took 3 big strappin guys to get it out the door of my trailer
Just noticed how the fan on the right is not even directed at the coils on top, I wonder if thats part of the problem. Seems like they should be mounted side by side and UNDER the coils. Who knows

[Overtaxed]

LOL @ "high school science project".

I could not agree more. I'm actually pleased with myself, from the little I could see plus reading the wiring and logical diagrams, the picture I had in my head is almost EXACTLY what I can now see from your great shot! Thank you for that.

And yes, "science project" is probably giving it too much credit. I mean, let's just talk about the fans for a minute and think this through. Those are computer fans, they are GOING to fail, not if, but when (but "every few years" is a good guess). Knowing that, you'd think that, IDK, you might make it possible to get at them without tearing the whole darn thing apart?! Kind of like spot welding on an oil drain plug, you KNOW you're gonna have to take it off someday, but hey, works great for the first 10K miles.

Next up, given that these fridges are super expensive, you'd think, even if they didn't want to make it easy to get at/replace the fans, they would, IDK, maybe spend more than .75 cents on them. The fans on mine are the bottom of the barrel computer fans; for those who are geeks, how about some Noctua fans at 20 bucks a piece (retail) with three phase motors and huge bearing life stats if you're going to "build it in" like this. It's like paying someone 1000 bucks to run a new 50ft electric line for you and then saying "nahh, I don't want to spend the extra 25 bucks to run 10 gauge wire, let's do it with 16". The cost of the wire in the ditching/running of electric is trivial to "do it better" but doing it after the fact is nearly impossible without major effort. I'm sure some people do this, but if I'm fishing in a wall or digging a ditch, if I need 2 strands of 14 gauge, I'm going to pull 2 or 3 strands of 12; why set yourself up to redo something??

I did find the problem. The upper right (in your picture) fan isn't engaging well, it's failing, I can see it when I apply power. It will spin up, but it's obviously not happy. My rig is under warranty, and I'm "not happy" about having to pull the fridge to get at that stupid fan, so it's going back to the dealer to fix that. Since they are going to be in there anyway, I'm going to ask them if they'll change both fans and put in something good (and I'll just hand them 2 new 120MM fans). Sure, cost me 40 bucks or so, but at least that should be the end of the problem.

Anyway, b**ch session over, here's what I'm doing/have done to fix this.

I cut the wires for the fan off the control board and hard wired them to 12V positive that's coming into the fridge compartment. No more blown fuses, and, because the fans are already thermostatically controlled, there was NEVER any reason to run it through the control board to start with. The "on" temp for the thermostat is 140 degrees, IIRC, so it's not like they'd be coming on all the time or anything like that. Anyway, so that's step 1, I'll post some pictures as I complete the project (hopefully today), but first thing, stop the fridge from turning off because of a failed computer fan; complete (and very easy). Cut two wires, take them back to a 12V source, and now you won't lose your food anymore if a fan starts hard.

Next up (for today, hopefully), I'm cutting the default thermostat out of there (140 degrees is REALLY hot before bringing the fans on IMHO) and putting in an adjustable thermostat that I got from Amazon:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

This will let me set any "turn on" temp I want, so I'm going to set it quite a bit lower to give the fridge more ability to dump the heat as fast as possible. I'm thinking 110 or 115, but that'll take some experimentation. I'm also installing 2 Noctua "Industria" line fans at the top to help pull out the heat. These fans are pricey, but they are IP67 rated (waterproof) and they will move a ridiculous amount of air when they are on full speed. I'm going to set it all up and see where I land first, I think they may be too loud at full rip, so I may need to add in a rheostat/fan speed controller for these guys; my primary reason for going with this fan is that it's watertight and of very, very high quality, not because I want a weedwacker running all night in my campsite.

Noctua Industria line fans:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Wiring diagrams:
https://norcold.com/wp-content/uploa...6B_SM_2118.pdf

The final step in this will be to get the dealer to replace the failing fan on the back, hopefully both of them, with something like this:
https://www.amazon.com/Noctua-NF-F12.../dp/B00KFCR5BA

Same fan as what I'll be installing on the vent, just a 120MM instead of 140MM.

If I were out of warranty and doing this myself (pulling the fridge to get at those fans), I would almost certainly make some other changes back there while I had it out, moving the fans up and making some sort of bracket to I could get to them if (when) they fail again without pulling the fridge. The lower fan (below the coil) is easy to get at, so that one doesn't worry me, but those uppers, they need to be a "field replaceable" thing, not something that's a multi-hour job (and, as you said, takes 3 guys to do!).

I agree with you, that fan on the right isn't doing very much. The entire thing is just like "huh" engineering, IMHO. Really, if I was doing it from scratch, I'd do away with all the fans on the fridge and make the upper/lower vents (design them for this) to be big momma fans, think "duct fans" or something like that. Make sure the entire compartment is well sealed (to the inside of the trailer) so you don't get "blow thru" from the fans and treat that entire back area as basically a plenum. That would work MUCH better, wind up with serviceable fans, a ton more movement of air, lower temps, lower noise levels (big ****** fans are quieter than little ones) and would just be a much better design. It would also do away with the "high school" wiring that's on the back, run all the wires on the trailer instead of the fridge (if we're going crazy here, let's say "in conduit" and "with a pull in the conduit if you need to work on it"), just put a thermostat up at the top of the compartment (instead of on the fridge) to decide if the fans should be on/off.

What's really laughable when you look at some of this "specialized" things, RVs and boats being the most obvious examples, is how just about anyone with even a background in electronics can figure out a "better way" to do it in than it's done. That's LONG since gone away in vehicles, when I look at how things are done in new cars/trucks I often think "holy crap, that's well engineered", but, in the past, it used to be that way there too. You'd pop the hood and see a spark plug wire run right over a header and know it's just a matter of time until it melts and starts to arc to ground, that kind of stuff. Hopefully the RV industry gets there some day, but, in the meantime, at least we have the gratification of engineering things "better than factory" without a PHD in thermodynamics or refrigeration theory. It's blindingly obvious how to make a lot of things "better" in an RV, this is just one of many examples.

[skippypg]

Where is this 5amp fuse in the 2118 Norcold.

[Grammy&Grandad]

It’s under the black plastic cover on the circuit board.

[Overtaxed]

It’s under the black plastic cover on the circuit board.

That's where mine was. I could get to it from the outside of the rig, on the bottom fridge vent slot, it's kind of in the middle, attached to the fridge. There are a few wires coming in/out of it. To get to it, you need to remove one wire (which has a quick connect on it). That wire is for the ignitor for the propane, IIRC. You'll also need a socket wrench to get the black cover off.

[skippypg]

okay thanks, I checked the fuse and is ok, the bottom fans runs,
with separated power source, top ones hard to get to maybe the
thermal disk.