View Full Version : Rm1350 defrost cycle

09-13-2011, 07:24 PM
Before you change fans or do anything with your Dometic RM1350 do the following.
Determine what time of day you want the unit to defrost. Preferably a night setting.(When turned on the unit will defrost after 60 hours of operation. So, if you pick 3:00 PM it will defrost at 3:00AM two and a half days later. My problem began when the power to our park went out at 11:00AM and I had forgot to turn on the battery switch in my 2011 Bighorn 3670. The power came on at 1:00 AM so the unit set a defrost cycle for 1:00 PM. During the hottest part of the day it was defrosting for two hours.
First, turn OFF the unit.
Next, be sure ALL 12 v. power is off both the battery and the converter.
Wait about 20 minutes. ( I tried 5 and 10 and they didn't work. Factory recommends only 2.)
Now, restore power and turn on unit. But, be sure you pick a time that will allow the unit to defrost during the night. I picked 10:00 AM so my unit defrosts at 10:00PM every day after the first 60 hours. With the two hour defrost cycle that gives the unit all night to recover and return to the cold condition.
Just came home from a month of using the unit and NO problems. On very hot days she kept the temp around 34-35 at the 4 setting and on cool overcast days she did the same at the 3 setting.
However, I believe that if the unit gets to cold it will automatically defrost. Twice that happened when we were gone for a period of time and before we left I noticed the temp was at 33-to 34 degrees. I reset the temp setting and unit began to work immediately. Check fins in fridge compartment. If wet and cool it's defrosting. If frosted and cold it's working.
The only problem I see with the refrigerator is that Dometic seems to think keeping its operating instructions a secret is how you win customers. They wanted me to take my unit 85 miles to the nearest dealer so I had to figure out how it worked myself along with help from Heartland.

09-13-2011, 08:16 PM
How do you know when the unit is defrosting? Ours gets a large build up of ice on the top and sides in the freezer area so I was thinking it did not have a defrost cycle on it.

09-21-2011, 11:51 AM
Open the refrigerator door and feel the cooling fins in the back. If frosted the unit is not defrosting. If cool and wet and refrigerator temp is rising it is in a defrost cycle. BE SURE you turn off ALL 12 volt power AFTER you turn off refrigerator. I turned off the battery switch and unplugged from the campground power supply. We don't use our refrigerator much after 10:00 PM so I set my cycle at 10:00 AM. That means it will defrost (60 hours later) between 10:00 PM and 12:00AM and have the rest of the night to recover. The defrost cycle will now occur every 24 hours.
Also, be sure you do not over cool. It appears to go into a defrost cycle if that happens. I just turned down the temp by going to a lower setting and problem went away. If we are going to gone for a period of time and temp in refrigerator is 33-34 degrees I lower the cooling setting to a lower number.