By Greg Illes
The Norcold and Dometic RV refrigerators are ubiquitous, and RVers who live away from AC power a lot of the time really have few other options. By and large they do the job, given their less-efficient (than house-style compressor types) gas-absorption technology.
However, there are several problems that can exist even in the best of RVs. Addressing these issues can help these little units live up to their (limited) potential.
INSTALLATION — The manufacturers are very particular about clearances in the dark area behind the fridge proper. These clearances are essential for proper airflow over the coils and fins of the thermal structure back there. Unfortunately, many manufacturers either don’t try very hard or their production quality is inconsistent. The end result (as I found in my RV) is that the clearance specifications are badly violated. It’s not difficult for a reasonably handy person to pull the fridge out, take some careful measurements and fabricate some trim to establish proper clearances. This way, the airflow can work as the designers intended.
FAN (cooling unit) — For standard fridges with roof vents, there are usually no fans installed. For my side-vent fridge (it’s in a slideout), there was one factory fan. The fan is thermally switched — to put more air through the enclosure if the top coil gets too hot. On warm days, my fan used to stay on for hours and hours, using up battery juice — and the fridge would still be several degrees too warm. The solution was to add one more fan. Now, the extra air flow really cools things down. The fans now stay on for typically less than one hour; and even though the current draw is twice as much, the result is better refrigeration and lower current consumption. Even if you don’t have a stock fan, adding one in could give your fridge an extra advantage. It’s fairly simple to do by tapping into the 12V circuit and using a standard thermal switch.
FAN (fridge compartment) — It’s well known that air inside the fridge is not at a uniform temperature from side-to-side or top-to-bottom. Several aftermarket battery-powered fans are made for “stirring” the inside air, and they all work so-so. Reviews generally speak about unreliability and quick battery exhaustion. Since the concept is sound, adding a permanent 12V fan is a set-it-and-forget-it solution. Caveats: You will have to drill and seal some small holes in your fridge, in a safe place. You should select a fan with fairly low current draw because it will be on whenever your fridge is turned on. I picked a fan from Digikey that draws only 1/8 of an amp, which equates to 1.5% of my battery capacity per day. (Less than one cell phone charger.)
Tackling any, or all, of these tuneups can make your fridge seem almost as good as a household compressor-style unit — so be handy, have fun, and keep your foods and drinks fresh and cool.
image: Pixabay (public domain)
Greg Illes is a retired systems engineer who loves thinking up RV upgrades and modifications. When he’s not working on his motorhome, he’s traveling in it. You can follow his blog at www.divver-city.com/blog.