Turbocharging the Norcold N 180.3 3-Way Fridge (Auxiliary Fan or Fans)

dsatwork

The initial fan was suggested and installed by a local RV Dealer, based solely on their opinion that if you are having issues with gas absorption refrigerators on hot days, then you need to add an auxiliary fan.   This opinion is echoed on the Norcold website in there FAQ's and there will be a link at the bottom of this post to my Norcold research paper I posted on the Facebook T@b Trailers Group. Before we go any further let me just add that initial fan and installation was paid for by Norcold. Sonrise RV installed a  Valterra A10-2618VP FridgeCool 12 Volt Exhaust Fan.  https://www.amazon.com/dp/B002N5YDG2/_encoding=UTF8?coliid=IAGM4FIW7DASI&colid=733TGZDKC8DS

The RV shop mounted the fan at the bottom of the compartment as shown in the pic below and the switch is mounted on top of the fridge. This fan operates off a thermostat that kicks on at 100 degrees and turns off at 80 degrees. The switch allows you to turn off the power to the fan, when the trailer goes into storage.

What I don't know,  is if you need to remove the fridge to mount it in this location. I don't think you do.

I'll discuss the switch in a little more detail below, when I explain how both the fans are wired together using this switch.

Adding the single Valterra fan was an improvement, but unfortunately this did not achieve the cooling results I was looking for. When I first had the Valterra fan installed, I did a test with 12 volts when the outside temperature was close to 90 degrees. With the single fan mounted at the bottom and no other modifications, it was still struggling to cool. The best I could do on 12 volts was refrigerator temps in the high 50s and low 60s. I believe that this fan with the baffle would have made a significant improvement, but unfortunately I never had a chance to test that combination.

I went through a couple of revisions but ultimately ended up the a single Mechatronics Fan Group Blower model B1232L12B-BSR-ND. This smaller fan can be mounted with wire ties to the fan vent. This fan is louder than some fans, but it moves a significant amount of air. It sits directly above the condenser and blows the air directly out of the vent. I believe this fan design provides better performance, because it doesn’t create back pressure that a 5” computer fans would have trying to push a larger area of air through the vents.  

 

 

I had to drill out the fan’s mounting holes to allow for the larger wire ties to be used. The vent tape makes sure that the fan exhaust out the vent and not back into the compartment.

 

The side view shows the mounting position and the wires that come with the fan are very small 24 gauge wire so I used shrink wrap to beef it up and add some protection for the wires.

 

 

This is what it looks like from the front and if you use the clear wire ties, they pretty much disappear into the white vent.

In regard to the fans and switch wiring.

At first I wasn’t sure but in the end I really liked the Valterra fan mounted against the wall shooting straight up the stack and that it comes on when the compartment reaches 100 degrees. The  switch provided with the Valterra fan works very well for this project. I ended up tying both fans to turn on with the switch, by making a pigtail that connects to the switch I could connect both fans to. When you turn on the switch, the blower that sits in the upper vent comes on and stays on because it is not connected to a thermostat. The Valterra fan only comes on when the temperature exceeds 100 degrees. The reason I like this configuration is that when the top fan is on it creates a constant draft. Air moving over the condenser fins, is what makes these gas absorption refrigerators work. If there is no draft, they cannot cool effectively. 

This is a lighted switch with a simple toggle switch that breaks the connection. The unused pole is for a ground and valterra advises you not to connect it because the fan is already grounded and it's not needed. With the ground connected it will use more amperage because the light will come on when you turn on the switch. I have it connected for now but will disconnect if it seems to be too much of a drain.