Refrigerator defrost cycle

[davidmurphy02]

I was surprised on our first big trip - four weeks - to find that the refrigerator fins did not accumulate frost like the refrigerator on our previous trailer. It always cooled fine, and on at least one occasion when I checked the fins I found water drops on them. I assume that current refrigerators have a periodic defrost cycle that keeps the fins from building up an accumulation of frost / ice. I can't find anything in the Dometic manual about that, however, so I'm asking here.

That's a nice improvement over our old fridge, if that is in fact the case - we were used to having to shut it off, remove everything, and do a complete defrost of the fins every few weeks depending on the humidity of the climate where we were camping.

On an unrelated note, one night when we were camped at over 9,000 feet the fridge burner evidently went out, I noticed it in the morning. I just turned the fridge off and back on, it stayed lit for the rest of the day. On another part of the trip we noticed after driving over a 10,500 foot pass that the fridge burner had gone out, we relighted it when we were back down at a lower altitude. Looks like when we are over 9,000 feet we'll need to keep an eye on it....hard to complain about that, and we rarely camp above that altitude.

[Vermilye]

Originally Posted by davidmurphy02

I was surprised on our first big trip - four weeks - to find that the refrigerator fins did not accumulate frost like the refrigerator on our previous trailer. It always cooled fine, and on at least one occasion when I checked the fins I found water drops on them. I assume that current refrigerators have a periodic defrost cycle that keeps the fins from building up an accumulation of frost / ice. I can't find anything in the Dometic manual about that, however, so I'm asking here.

That's a nice improvement over our old fridge, if that is in fact the case - we were used to having to shut it off, remove everything, and do a complete defrost of the fins every few weeks depending on the humidity of the climate where we were camping.

On an unrelated note, one night when we were camped at over 9,000 feet the fridge burner evidently went out, I noticed it in the morning. I just turned the fridge off and back on, it stayed lit for the rest of the day. On another part of the trip we noticed after driving over a 10,500 foot pass that the fridge burner had gone out, we relighted it when we were back down at a lower altitude. Looks like when we are over 9,000 feet we'll need to keep an eye on it....hard to complain about that, and we rarely camp above that altitude.

I'm not sure there is an actual defrost cycle like the one in my household refrigerator, but here is a image from the SensorPush thermometer. It records the temperature & sends it to my phone - this is from 4:00PM - 10:00AM. Notice the short on/off cycles of the refrigerator temperature. Very small, short swings, but I suspect the fins get warm enough to melt any frost. The same swings take place in the freezer.

[cpaharley2008]

If you install a fan that blows over the fins in the refrigerator it will keep them dry or help the cooling by moving cool air around inside. I have had dual 12v fans on every refer in my Escapes and have never had to defrost them even after 2-3 weeks of use.

[alanmalk]

Originally Posted by cpaharley2008

If you install a fan that blows over the fins in the refrigerator it will keep them dry or help the cooling by moving cool air around inside. I have had dual 12v fans on every refer in my Escapes and have never had to defrost them even after 2-3 weeks of use.

Are the fans very quiet, or can they be heard in the cabin? I'm tired of having to melt off the 2-3 pounds of frost that accumulates in a month, but don't want to add any noise to the sleeping area.
--
Alan

[cpaharley2008]

You can turn them off at night, in the 19, sleeping next to the refer there was a hum, in the 21 away from the refer, not a sound

[davidmurphy02]

I wonder if the defrost function is something that has changed just in recent years? After a month on the road with no frost or ice on the fins I'm pretty sure it's getting rid of that on an ongoing basis automatically. Not what I was expecting, but sure makes life easier.

[Vermilye]

So far I've made 2 long trips (270 & 275 days) with the 2017 21, and have not had to defrost ever. I do have a set of computer fans mounted on the fins that blow over them. Very quiet - you can only hear them with the door open.

[alanmalk]

Is that a homemade bracket that supports the fans?

[Vermilye]

Originally Posted by alanmalk

Is that a homemade bracket that supports the fans?

No, that is the way the fan set is designed. Originally designed for computers. An eBay purchase, although I don't see the one I purchased. They appear & disappear; I suspect someone buys a bunch from China & sells them until gone. I paid around $16.00... Here is a more expensive & fancier one.

[rubicon327]

Originally Posted by alanmalk

Is that a homemade bracket that supports the fans?

Fans like Jon’s are available commercially from RV Cooling Unit Warehouse and others
https://rvcoolingunit.com/Dometic-Ev...-P3239952.aspx