Fridge runs warm when temperature climbs into high 80s

[Drew_A_]

Greetings,

We have a brand new 2021 Imagine 22MLE with a Dometic 2882 installed in a slide. The fridge has been running in the high 30s with the temperature control on "3". (This unit has temperature control 1-5, so "3" is in the middle."

Just recently we had temperatures climb into the high 80s and we were camping in direct sun without shade. I heard the condenser side fan turn on, but the fridge temps climbed into the low 40s. The freezer runs around 0 to a few below.

I'm wondering if an internal fan on the evaporator fins will help. I will be checking the condenser side fan and see if more airflow there is needed.

Any experience with the internal fans helping or is increasing the condenser side airflow more important.

Thanks, Drew

[smthbros]

This phenomena is well known to those of us who live in old, less well insulated houses. As the outside temperature drops, so does the temp of the house wall. The objects inside the house now lose more heat to the wall. However the temp of the very small area where the thermostat is located remains warm enough for the stat to not call for heat. This is why modern houses have supply runs located near outside walls as well as having better insulation.
While in the fridge the heat is moving in a different direction, the physics are the same. Increasing the insulation of the cabinet and perhaps providing some air circulation inside the fridge to even out the inside temps may help mitigate the problem.

[Old-Biscuit]

ScottG wrote:

dougrainer wrote:

ScottG wrote:

Old-Biscuit wrote:
When the outside air temps increase YOU have to turn up the temp setting to '4' or '5'

I have found this to be true of my krappy Norcold as well but I don't understand it. If the fridge is using a "thermostat", why do we have to change the setting when the outside temp changes???

This is one of the things that's keeping me from doing a compressor conversion; I'd have to keep that stupid thermostat.

You turn COLDER to make the refer run longer in a cooling cycle. Sounds crazy, but it is the nature of RV refers. You would think if the refer can keep up at setting 3, it is obviously running and trying to get to temp, then why set at 4 or 5. I have no idea, but that is how it functions. Doug

PS, my theory is, it catches up at night and because it starts out in the morning COLDER, then it keeps up better thru the heat of the day.

I would never have guessed anyone would make a stat work like that but your theory explains everything that goes on with these things.

Scott

On '3' it can keep up when ambient temps are below 80*F
As temps rise Longer heating cycles (more cooling) is needed
That is why you have to turn the temp settings up

Thermostat is calibrated for range of 34*F--46*F based on temp setting with feedback from thermistor (which measures FIN temp and is 10*F colder then air temp)

All this together PLUS the Draft across backside of fridge make an absorption fridge function

[Cummins12V98]

garyemunson wrote:
I added 2 fans to the top vent of our Norcold. Used 2 small car radiator fans wired in series to slow and quiet them down. HUGE difference in hot weather operation.

I did the same with much smaller computer fans on a switch. Worked GREAT!!!

[ScottG]

dougrainer wrote:

ScottG wrote:

Old-Biscuit wrote:
When the outside air temps increase YOU have to turn up the temp setting to '4' or '5'

I have found this to be true of my krappy Norcold as well but I don't understand it. If the fridge is using a "thermostat", why do we have to change the setting when the outside temp changes???

This is one of the things that's keeping me from doing a compressor conversion; I'd have to keep that stupid thermostat.

You turn COLDER to make the refer run longer in a cooling cycle. Sounds crazy, but it is the nature of RV refers. You would think if the refer can keep up at setting 3, it is obviously running and trying to get to temp, then why set at 4 or 5. I have no idea, but that is how it functions. Doug

PS, my theory is, it catches up at night and because it starts out in the morning COLDER, then it keeps up better thru the heat of the day.

I would never have guessed anyone would make a stat work like that but your theory explains everything that goes on with these things.

Scott

[dougrainer]

ScottG wrote:

Old-Biscuit wrote:
When the outside air temps increase YOU have to turn up the temp setting to '4' or '5'

I have found this to be true of my krappy Norcold as well but I don't understand it. If the fridge is using a "thermostat", why do we have to change the setting when the outside temp changes???

This is one of the things that's keeping me from doing a compressor conversion; I'd have to keep that stupid thermostat.

You turn COLDER to make the refer run longer in a cooling cycle. Sounds crazy, but it is the nature of RV refers. You would think if the refer can keep up at setting 3, it is obviously running and trying to get to temp, then why set at 4 or 5. I have no idea, but that is how it functions. Doug

PS, my theory is, it catches up at night and because it starts out in the morning COLDER, then it keeps up better thru the heat of the day.

[wnjj]

Drew A. wrote:
One thing I just noticed is that the thermistor on the fins can be moved up/down just like on fridges that do not have temperature control settings. Is moving the thermistor up on the fin something I should try? Moving the thermistor is not mentioned in the Dometic manual.

The fridge is already trying its best to cool and falling behind because of thermal issues. Moving the thermistor won’t help.

[sparkydave]

I added a 12 volt computer fan to help move air out of the condenser vent when I discovered that the refrigerator would warm up if the sun was shining on that side of the camper on a hot day. Made a world of difference since the heat would build up inside that compartment.

[ScottG]

Old-Biscuit wrote:
When the outside air temps increase YOU have to turn up the temp setting to '4' or '5'

I have found this to be true of my krappy Norcold as well but I don't understand it. If the fridge is using a "thermostat", why do we have to change the setting when the outside temp changes???

This is one of the things that's keeping me from doing a compressor conversion; I'd have to keep that stupid thermostat.

[dougrainer]

Ivylog wrote:
Proper installation in a slide is critical. Using a mirror determine how much of a space there is between the coils and outside wall... one inch max. Likely there is a dead air space above the top vent.
Still under warranty? Make them install it properly... 1’” of clearance and add a angled baffle at the top vent so there is no dead air space. Fans are a bandaid, except for a NoCold 1200.

The upper Fan inside the upper door on a slide installed refer is NOT a Band aid. I will tout my 42 years as a Trained RV tech and also the fact that over the years I have installed countless upper fans blowing out and have 100% effective better cooling. Makes no difference if a 1200 or a standard 2 door refer Norcold or Dometic. Yes, the baffle to direct air ABOVE the fins curved to get to the door is also critical. Doug

[mr_andyj]

Yes, this is normal for absorption fridges.

keys are:
keep fridge side of camper on the North side, in shadow, this helps a lot.

The fans will help.

The construction of the space behind the fridge should force all the air over the coils, not around it. There should be a baffle or something so all air goes by the fridge parts.

Inside the fridge the fins need air circulation, so dont push the bread or bags up against the fins.

If more insulation around the fridge box is possible then add another layer, or check that there is good insulation around it already.

[Ivylog]

Proper installation in a slide is critical. Using a mirror determine how much of a space there is between the coils and outside wall... one inch max. Likely there is a dead air space above the top vent.
Still under warranty? Make them install it properly... 1’” of clearance and add a angled baffle at the top vent so there is no dead air space. Fans are a bandaid, except for a NoCold 1200.

[wa8yxm]

Note that Evaporator and condenser are Compressor Driven terms.
The terms are different for absorption units.
That said we know what you mean so it's not a problem.

[garyemunson]

I added 2 fans to the top vent of our Norcold. Used 2 small car radiator fans wired in series to slow and quiet them down. HUGE difference in hot weather operation.

[MEXICOWANDERER]

From hard earned experience...
I used to store only ketchup, pickles, mustard, syrup, and the like in the door. What I felt were sensitive foods got first tier choice to the rear. Food safety and temperature.