Dometic 1350 temperature fluctuations

[Loneoak]

The temperature fluctuates wildly in our fridge. Sometimes it is 37 (my happy place), and then a few hours later it goes up to 44. (This happens without opening the fridge). We have friends who have an identical trailer (same model and year). They are having the same problem. Both of us are in Florida.

We called a mobile RV repair. The guy came and hot wired the fan, making the fan on all the time. He figured maybe it was the switch. This did not solve the problem. I got up one morning and found it at 40, and this is when it was a cold night. Normally the fridge is at its coldest first thing in the morning.

He also left us a spare thermistor, and showed DH where to plug it in. DH and friend tried, but they did not know how to thread it through to the fridge, so they gave up on that. We called them back.

They showed up while we were out, and the guy plugged in the new thermistor. The sensor end was then outside the fridge. Of course, the temperature shown on the fridge went up into the 50s, and the actual temperature in the fridge got into the "too cold" category. I have a fridge thermometer in it.

Does anyone have any idea what might cause wild temperature fluctuations like that?

[tspoon]

I put two fans on the fins inside the fridge. I have 2015 305rl with 1350 fridge. That fixed my problem with temp going up.

[Loneoak]

I have one in the fridge and our friends don’t have one at all.

[ChuckS]

My 2014 has the RM1350 fridge. No temp fluctuations. I’d start by checking the door seals and see if there is a gap anywhere... pay close attention to the lower seal area. A dollar bill should stay tight in the door seal with doors closed ... if not you need to address that issue first.

I’d also remove the outside upper and lower vent covers for the fridge and blow that area out with an air compressor. Use low pressure..about 25 psi...gently blow out the condenser coil area located at the upper vent.

Make sure the baffle is still in position at the upper vent area.

Mine stays around 34 in 100 degree temps

[jcurtis934]

Assume you have the installation manual. If you compare what is behind the top outside vent, does it match what is in the manual? Is the bottom airflow metalwork meeting the requirements and is the top metalwork meeting install requirements?

[1retired06]

We also have the RM1350 and we are also in Florida. Ours runs between 35 and 39, and temperature setting is on three. I have two 4 inch AC fans installed in the bottom vent outside, facing upward, to help push the heat out. The fans at the outside top vent (noisy ones) seldom kick in as a result. Defrost mode will cause some temp variances; putting anything warm in the frig will cause the temp to jump, we either stick the warm items in the freezer for 15 minutes or so, or stick in our bar frig outside.

[Loneoak]

I am wondering if this defrost mode could be the culprit. Last night, it was at 37, then it suddenly started going up to 45 before DH went to bed. He mistakenly set the temperature to 2, from 3, not realizing that lower numbers mean less cold. I got up early to find the fridge at 48, the set it to 4. I also turned the fridge off and then on again after a few seconds. None of this made a difference. A couple of hours later, the temperature started to drop again.


This is after 3 days of the temperature being perfect. I had it set on 3 as the outside temperature is quite warm right now here in Florida.


Does anyone know how this automatic defrost works, how often it does its thing, and if these temperature fluctuations are normal? I just don't like the temperature going into the high forties and low fifties. I am concerned about food safety.

[Creeker]

You should be concerned with those temps. The fix is adding fans to move more air through the upper outside fins and out the upper vent. It has been documented here by many of us. Ours went from being set on 5 (coldest) and varying temps up to 50 to being set on 3 with steady temps in the mid 30's.

Nearly all RV fridge problems are the result of poor installation by the RV manufacturers. They simply do not adhere to clearance and baffling to move
air across those outside fins and out the upper vent.

[dieselguy]

Have you tried putting a thermometer inside your fridge to compare it to whatever you are currently monitoring? You may be chasing a ghost. Or ... does the inside really feel not so cool? We keep a small battery powered fan inside the fridge to move air around ... it helps even out temps somewhat. I added the ARP unit years ago. It makes the outside fans come on sooner and stay on longer.

[Loneoak]

Originally Posted by dieselguy

Have you tried putting a thermometer inside your fridge to compare it to whatever you are currently monitoring? You may be chasing a ghost. Or ... does the inside really feel not so cool? We keep a small battery powered fan inside the fridge to move air around ... it helps even out temps somewhat. I added the ARP unit years ago. It makes the outside fans come on sooner and stay on longer.

Yes, I’ve had one in there for a while, and the temperature that the fridge is displaying is right on. I do have a fan in there.

What bugs us the most is the intermittent nature of this problem. It will be fine for several days, then for no reason at all, the temperature starts to climb. Last night it started well after the fridge had been opened at all.

[boisesmith]

What's the ARP you used?

[Loneoak]

Originally Posted by boisesmith

What's the ARP you used?

What is ARP?

[ChuckS]

https://www.arprv.com/dometic-rm1350.php

This is the ARP Fridge defend for Dometic 1350. Personally I don’t see the need

[rohrmann]

This is from the Dometic 1350 fridge owners manual:


The refrigerator has been design with an automatic cooling
unit cycling system that helps reduce frost build up in the fresh
food compartment. The first automatic frost reduction cooling
unit cycle begins 60 hours after turning "on" the refrigerator
(for best operational results the refrigerator should be turned on
anytime between 4 and 10 PM), and will last for approximately
120 minutes. Thereafter, the cycle will automatically repeat
every 48 hours as long as the refrigerator continues to run.


We have a Norcold, which also has a defrost cycle system, and we see a temperature fluctuation as well and is usually from the defrost cycle. We also have the ARP device, and it has kept our unit working well, especially after not having the ARP device and having the cooling unit fail twice in one year. Our fridge is usually about 34 to 40 degrees and the freezer section runs from 10 to 20 degrees. Along with the ARP device, we also have the ARP fans that the device controls independent from the factory fans, and this really makes a huge difference in how the fridge operates.

[Anatnom]

Lots of good advice here but I’d like to add what we did. I purchased a small fan for internal use inside the fridge .
it runs on a couple of AAA batteries. This fan has really worked well for me and doesn’t take up much space. Just a suggestion.

[Loneoak]

Originally Posted by Anatnom

Lots of good advice here but I’d like to add what we did. I purchased a small fan for internal use inside the fridge .
it runs on a couple of AAA batteries. This fan has really worked well for me and doesn’t take up much space. Just a suggestion.

I did that last year and it is running all the time. It's the intermittent nature of the problem that drives us nuts. I have been recording the temperatures, and it tends to go up every three days. I expect it to happen again tomorrow.

[ChuckS]

First pic should help folks understand the defrost cycle time on the RM1350

Second pic details how the factory cooling fans should work.

On the outside fridge lower access panel inside the panel is a small black corrugated drain tube.. make sure the tube is nit broken off and also verify there is a small white plastic plug inserted into the end of the drain tube.. the plug has a few small holes in in.. make sure they aren’t plugged.. Don’t leave the white plug removed... it’s there for a purpose

[Eagleback]

We live in Naples full time for 6 years and its unfortunate, but the rv fridges just do not work well here as it is just too warm for them to keep a constant temp. when the temps get in to the high 80's and above the temp also rises in the box. No amount of fans or monitoring systems help enough to keep the food safe and cold as we have done all that. Out went the Norcold and in went a residential fridge. Except for the maybe saluns and dometic upgrades the Norcold replacement to a residential is by far the best upgrade we have done as we no longer have spoiled food and milk actually last for more and 4 days.

[DonMar]

We have been having the same temperature problem with our Norcold refrig. When we were passing through Texas it was hot & humid and went up to 60 degrees. Had it checked out and a new cooling unit was installed. Unit hasn't been consistent. One day it will be at 32 -36 degrees and the next it will be heading towards 44 degrees. I find that when the humidity outside goes up, the refrigerator temp starts to go up. Supposedly the door seals where checked. We had a problem with the flange not closing properly and it was replaced. I find it is not closing properly again but we know to manually close it. Suppose to have the doors replaced next week. I want to install the fans on the outside to pull the hot air out but not while it is still under warranty.
I thought we were the only ones having the problem. Interested to hear how your issue gets resolved.

[rohrmann]

We have Paul Unmack and his wife Mao here at our Quartzsite Circle, and they just put on a presentation this afternoon. The ARP device will not void any warranty and their model that controls the additional fans works great, as we have had an ARP device, now called Fridge Defend by ARP, for close to six years, ever since we had our cooling unit replaced the second time, and our fridge is still working great. The sooner you protect your fridge with the ARP device, the sooner you help protect it from damage from excessive heat at the boiler of the cooling unit. This is their web site, https://www.arprv.com/