Does an auxiliary fan improve refrigerator performance?

GHatfield

We've owned several RVs over the years and I've put auxiliary fans in all of them to hopefully improve the performance of the adsorption refrigerators. So when we bought our 2019 T@B 320 BE a few weeks ago I ordered this fan from Amazon (Noctua NFS12APWM). I had installed several on the Airstream Bambi we owned previously. They are known for being quiet and durable. I mounted it on the left side of the top grill opening for the refrigerator. Mounting is a bit of a challenge since the sidewall is mainly foam. So I attached it to the wood framing that runs down the side of the opening and then also attached it to the plastic grill frame. I ran the wires down through the drain opening and then to the battery. The line is equipped with a push-button switch near the battery and a 2 amp fuse. There are probably better ways to mount the fan, but this is what I ended up with.  By using the drain opening I didn't have to remove the cooktop to get to the refrigerator wiring to connect to 12V.    

But does it improve the performance of the Norcold N180.3D refrigerator? We store our 320 in a garage so it is away from the wind. This makes it easy to measure temperatures in a relatively controlled environment. We have a wireless thermometer with two sensors. I used one on the inside of the frig and one outside. I set the refrigerator to run on 110V and at the maximum setting. Then I recorded the refrigerator temp and ambient temp over 7 hour periods. See the graph. Ambient temps were very similar for the two runs (80-84F).  With the fan running the refrigerator cooled faster and got colder. Not a huge difference but significant.

I also measured the max temperature of the top ventilation grill for the refrigerator. Without the fan it ran about 148 F (IR thermometer) and with the fan running about 112 F. I would not be surprised if that plastic grill cover will discolor over time after being exposed to 148 F for hours on end. Another reason to install a fan.

db_cooper

Our 2015 only came with one fan that blows up across the heated pipes on the left of the Norcold.  It is controlled by a thermostat, and while the thermostat worked, it cooled OK, even in our typical upper 80 summer weather.   When the thermostat failed,  that one fan didn't run, and it made a huge difference.  It failed first day of a week long trip, and never could get the fridge below 45 - 50.  Turned it into a wine cooler for the rest of the trip, and put the food in an ice chest.

Once we got home, and I figured out it was the thermostat, and not something more serious,  I ordered 3 of the Noctura fans.  I replaced the noisy existing fan, and put in a new thermostat.  Then I put 2 fans in the outside vent and wired to the thermostat.  Some have put the outside fans on a switch, but I didn't bother, figured I could go back and do that if I wasn't happy with the performance.  Fridge cools better than ever,  and now it's much quieter to boot.

We also added one of these, and it helps the fridge cool more evenly.

https://www.amazon.com/Valterra-A10-2604-FridgeCool-Volt-9-1/dp/B0006MRQYU/ref=sr_1_6?dchild=1&keywords=rv+fridge+fan&qid=1590448584&sr=8-6

edited to add we only boondock and run the fridge on propane.  the extra fans haven't hurt our battery power significantly, running dual 6v batteries.

ChrisK

I have 4 fans on my fridge. My T@B came with the single fan by the coils. I added a second fan to that. I added the side vent fan on a switch. I also added a fourth fan above the fridge on the left side that is on a switch. I can turn it off, have it activate via the thermostat that controls the first two fans, or have it on all the time. I live in AZ where temps can get "warm". I've tested it in over 100 degree heat and I can still cool the fridge to safe levels. Most of the time, I barely have to turn the fridge setting to about 1/3 power. I also added a vent to the plastic panel to the left of the fridge.

https://tab-rv.vanillacommunity.com/discussion/7584/mistakes-and-mods-and-keeping-my-fridge-cool-update-6-5-19#latest

The only time I have fridge cooling problems now are when I run it on propane at high altitudes.

alanerickson

I have a 2018 320 with a Norcold 180.3 fridge in it.   We just got back from a week and a half in Wyoming and struggled when the ambient temperatures got over 90 and while on 12V.   We had to buy and add ice to the fridge on a few days, but even then the fridge temperature got close to 50F and we did have to throw away a little food.  

This model does not have a fan at all as some of you know and so my first approach is going to be to add some.  I'm looking at a Noctua 120mm like was used in the above picture.  The picture is a little fuzzy but it looks like it's a NF-S12A PWM that's being used.  

My questions are should I use a variable speed fan or not and how much static (or fan speed) do I need?  The other question would be fan on/off.   Is thermostatic recommended or just an on/off switch?  On/off seems less likely to have problems, but then you have to remember to turn it on or off.  And lastly I was looking at having two 120mm on the inlet vent and if that doesn't help enough to go to two more on the outlet.   Kind of expensive, but the alternative would be to go to a higher rpm fan which would be louder.   

So I guess the simplest and quietest would be two of the 800rpm fixed speed fans on the inlet and manually control.   Do you think this is sufficient or would I probably end up adding to this?

Thanks.

rcuomo

Alan, I installed the fan kit that used to be available from NuCamp. Fixed speed on simple switch. Noticeable difference in countertop temps, about 10 degrees cooler.  Haven’t really noticed internal difference but I assumed if the cabinet is running cooler the fridge has to be running more efficient. 

rcuomo

https://tab-rv.vanillacommunity.com/discussion/7535/norcold-3-way-auxiliary-fan-kit-my-install-in-2018-t-b-320s

MarkAl

Anybody do tests with an aux fan for the 2021 320S' 12Volt refridg? I would think it's always a trade off of temp performance vs normal outside temp loads and cost.

Denny16

The new two way fridges have a thermostat fan already installed in them.  The three ways, have both with manual run switch.  A cooling fan in the back of the fridge does improve its performance.  This has been established in previous posts on this.
cheers

alanerickson

Thanks.   Looks like I'll start out simple with fixed speed fans and an illuminated on-off switch.  If I'm propane since the exhaust and supply are in this cabinet I'm wondering if I should have the fans on or off?

webers3

While work camping in day temp in high 80s and low 90s I could not get the fridge temp below 50. Reading previous posts about installing a fan to help bring the fridge temp down I took of the top vent cover and stuck a small box fan blowing directly into the vent. Left it running for 2-3!hours but did not see it making much difference. Not a scientific but practical test. My result shows that the effort in installing a fan is not worth it. 

Denny16

The top vent is the exhaust vent, so you were blowing the heat back into the refrig unit.  You need the fan below of behind this vent to draw hot air out through this vent.  Cool air enters in the bottom vent.
cheere

webers3

Oh I see @Denny16. Will try the same with the lower vent when the day temps go back to high 80s.

alanerickson

Went a little over the top and added two fans to the exhaust.  3D printed the brackets and that worked perfectly.  Held in with 5 pocket screws each and so I don't think it's going anywhere even when bouncing down the road.   Fans are 80mm Noctua brand, 12V, and these are the ULN (ultra low noise) model.  The brackets are thicker than they look and you can get an idea of that from the one picture where it shows up close and screwed to the bracket.

Tested it out and very little temperature rise in the air coming up but not blowing like crazy either.

Used Wago brand lever connectors for my electrical which short of soldering should be good as anything.

If anyone wants the model of the bracket you can download them at thingiverse at the link below.

Also added an illuminated fan switch since the original setup didn't have anything.

https://www.thingiverse.com/thing:4597251

Tampakayaker

Nice work

webers3

@alanerickson Did you notice any measurable difference in the fridge performance since adding the fans?

ChanW

We have the earlier 3 way, and it definitely helped to add the exhausting fans.
The heat retention around the fridge was bad enough that the counter would heat up, especially when in propane mode. 
The fans pull the heat out of the fridge 'compartment', and out of the trailer itself.
It definitely helped it to cool.

Dalehelman

We did this to also increase air flow.

Lil_Lucy

We also did the @Dalehelman mod.

VictoriaP

alanerickson said:

Went a little over the top and added two fans to the exhaust.  3D printed the brackets and that worked perfectly.  Held in with 5 pocket screws each and so I don't think it's going anywhere even when bouncing down the road.   Fans are 80mm Noctua brand, 12V, and these are the ULN (ultra low noise) model.  The brackets are thicker than they look and you can get an idea of that from the one pick where it shows up close and screwed to the bracket.

Tested it out and very little temperature rise in the air coming up but not blowing like crazy either.

Used Wago brand lever connectors for my electrical which short of soldering should be good as anything.

If anyone wants the model of the bracket you can download them at thingiverse at the link below.

Also added an illuminated fan switch since the original setup didn't have anything.

https://www.thingiverse.com/thing:4597251

Outstanding retrofit! Sigh. I really, really hate that nuCamp left something this critical up to owners to deal with. Some of us have neither the skills, the tools, nor the physical strength to pull the fridge. This should have been handled before it ever left the factory; the fridge overheat problem is evident to anyone who’s ever run one in summer.

I really need to find someone to add a fan or two to mine.

ChanW

@VictoriaP, I didn't have to pull the fridge. I was able to do it all from under the stovetop, after pulling that.

alanerickson

webers3 said:

@alanerickson Did you notice any measurable difference in the fridge performance since adding the fans?

From the little bit I tested it ........ yes.   Turned the fridge on in my garage when the ambient temperature was around 80F.   Within an hour I was a couple of degrees above 40 F in the fridge.  Came back in another hour and it was around 30F.   Normally it would take 2-4 hours to get to 40F alone.    But no detailed testing with graphs and stuff like that.   But so far I'm pretty impressed at how much better it's cooling and the exhaust air temperature is much lower and it must be at least 30F cooler right by the coil.

I also glued in the door gasket and I think that may have also helped, as we often get a bit of condensate in the fridge.  Have to see if that's reduced next time we camp.

This all started when we went to Wyoming this summer, the ambient temperature was 100 F, and the refrigerator would warm up to 50 F during the peak of the day.  I'm sure it will behave better and hopefully it's fixed it to where the fridge temp doesn't get above 40.

Verna

@VictoriaP, nüCamp has no idea in 2014  that the 2015 T@B’s with Norcold’s new 3-way fridge model needed an extra fan. It was installed per Norcold’s specs. 

2014 was a mild summer, but 2015 was hot!  There was chocolate, butter, even bread wrappers melting to the counter tops. Marvin and Ed (formerly in the repair shop) figured out the Norcold fan at the left side did not draw the hot air out. They put the muffin fan (computer fan) into the outside vent and that solved the air flow problem. 

It’s not always nüCamp’s fault when the best plans go awry. The manufacturers some times are at fault for not having proper testing. 

VictoriaP

Verna said:

@VictoriaP, nüCamp has no idea in 2014  that the 2015 T@B’s with Norcold’s new 3-way fridge model needed an extra fan. It was installed per Norcold’s specs. 

2014 was a mild summer, but 2015 was hot!  There was chocolate, butter, even bread wrappers melting to the counter tops. Marvin and Ed (formerly in the repair shop) figured out the Norcold fan at the left side did not draw the hot air out. They put the muffin fan (computer fan) into the outside vent and that solved the air flow problem. 

It’s not always nüCamp’s fault when the best plans go awry. The manufacturers some times are at fault for not having proper testing. 

My opinion on Norcold cannot be posted on a family friendly forum, so no, it’s not entirely nüCamp’s fault. I remember when Norcold was the preferred choice over Dometic way back when. Things change, alas! 

Not disagreeing that a new model year with new appliances may encounter problems. I will stick by my statement though—I have a 2019, which still has nearly the same problem, even though it was an issue posted on this forum following a second fridge change to the n180.3 (which happened a year or two before mine was built). A simple search shows this topic has come up multiple times with the propane fridges on the 320 regardless of fridge model, including in this thread, which makes it clear to me this has been an ongoing problem for years. 

Those of us who have the model year 2018-2020 fridge are left on our own to deal with a fridge that is known to overheat in warmer weather almost as much as the previous model. All for lack of a $20 vent fan and switch that should have been installed on the line at the factory. A single model year is plenty of time to recognize that a familiar problem seen in previous models still exists and that the same fix is needed. nüCamp is generally good at changes on the fly like these when necessary, but I do feel they dropped the ball here.

@ChanW, thanks for the heads up on removing the stovetop, that’s very helpful. I’ll have to take a look and see if that puts it back in the realm of something I can do. I lack the proper tools and connectors and such to work with wiring, along with the skills, which makes projects like this a bit more expensive and usually a lot more time consuming than for many folks here. But hey, I learned how to check a battery with a multimeter, maybe I can figure this out too. 😁 

Dalehelman

Our 2015 with the 3 way fridge has worked fine for 5 years. Both in very hot weather 100* and very cold temps single digit and below. My issue was not with the fridge it self. It was how hot the counter top would get. Although it never caused a problem. 

All absorption type fridges are designed to vent up through a wall and out the roof. Convection works very well in this case.
Unfortunately TABs do not allow for this type of installation, and convection is not very efficient horizontally. Norcold  did redesign them to vent on the right side, and NuCamp added extra larger vent to the outside. This is a great improvement for removing heat and better service access. All and all I think both companies have worked to address the issues. Hence the reason for the new compressor style. Given the chance I would still keep my 3 way. As it uses almost no energy except for propane when dry camping. Our first experience with a propane fridge was in a 1972 Commander motor home. Over the years I can only guess how many we have owned.

alanerickson

webers3 said:

@alanerickson Did you notice any measurable difference in the fridge performance since adding the fans?

Just a little update on this.  I was the one who added the dual fans above.  We went camping a couple of weeks ago (when it was still reasonably warm) and as a side benefit the temperature control actually seemed much better.  Normally with the fridge it seems like you're always having to adjust between too cold and warm.   With the fans it seemed to stay much more constant, right around 34F.   I think maybe the reason for that is because before the fans were there you had to "turn up the heat" in order to get a decent draft and start cooling, but then once then when the draft started it would overshoot.  This separates those two, so you can put a little heat in and it is removed and you don't have to worry about draft.  Or at least that's the theory.  Anyway, it definitely is better.

And we have a 2018 which doesn't have the side panel as others have shown.   The top getting hot isn't an issue so whatever change norcold made then took care of that.  Unfortunately it also changed things so the cooling wasn't the greatest.  As Murphy says, every solution creates another problem.

yshelburne

@alanerickson I stumbled across your mod and love it. I have a 2020 with the same Norcold 180.3 and heating issues. I’d like to install the fan like you did. I see where your wires come in for the toggle switch (nicely done with those Wago connectors). In your pic, where is the wiring for the fans? Is it the blue and white wires coming in to the left side of the terminal block? I haven’t pulled my stove top yet so I’m just comparing your pic to the wiring diagram in the manual. Thanks!