Dometic Fridge Mystery

[gepaine]

We have been on the road for almost 2 months in our 24-foot Cougar TT. At about the 6-week point, our Dometic fridge became seriously iced up. About 25% of the cooling fins had ice built up between them about 2 inches deep. I went online and found that apparently this is common to RV fridges. They need to be defrosted periodically when used for extended periods. Sounded about right to me, but not having a large ice chest with me nor wanting to take time out of our planned activities to defrost it, I looked further for another solution.

I found a product advertised that is an assembly of 2 or 3 small fans that sit on top of the cooling fin assembly and blow air down thru the fins. The company claims that it will not only prevent ice build up, but will also remove ice build up that is present when installed. I thought about the $20 fridge fan I have that runs on 2 D cell batteries. (The advertised fan assembly had a FAQ that said the typical $20 fan won't defrost ice build up.)

Well, the company is wrong. The D cell fan removed ice build up in a small area of the cooling fins when the fan was directed right at the fins for about 6 hours. Then move the fan over a couple of fins for another 6 hours. Over a period of about 3 days I removed all of the ice build up this way.

Now the main reason for this post.

Prior to using the D cell fan, the fridge was icing up, but was still maintaining the fridge section around 34 degrees. As I used the D cell fan, the temp rose in the fridge to as high as 45 degrees and would not go down no matter how low I set the "thermostat" (thermistor). Asking myself what really was different since the temp started to rise. Of course, the difference was the use of the D cell fan. So I removed the fan, and within a few hours, the temp dropped back to the low 30's.

Given that better air circulation is supposed to result in better cooling, can anyone speculate as to why aiming a small D cell fan directly on (within an inch of) the cooling fans would cause the temp to rise?

[jsmith948]

Perhaps, because the fan was directing cool air on to the thermister, the unit did not come on?
We recently made a 16 day trip to WA & OR. The DW had the D-cell fan on the narrow shelf in front of the fins and we had no issues. At the end of our trip we had some ice build-up in the freezer but not the fridge. Our fridge stayed in the low 30s (well - the blue zone on the thermometer). The freezer stayed at around zero. I think the ice in the freezer was due to the humidity at our DS's house in Seabeck.

[MadMax]

Originally Posted by gepaine

Given that better air circulation is supposed to result in better cooling, can anyone speculate as to why aiming a small D cell fan directly on (within an inch of) the cooling fans would cause the temp to rise?

Perhaps the fan itself is producing heat (from its small motor) that is causing the overall temperature within the fridge to rise....