Dometic Refrigerator cooling

[Garry_Gayle]

I have a Dometic RM1350 Refer; when turning on the unit works great whether gas or elec. on setting 4 refer runs about 35 deg. freezer is 0 deg. then around 4 pm it warms to around 40 deg. then by 3 am its back to 35 deg. again. After about a 7 to 14 days at 4 pm it warms to 45 - 50 deg. but then only cools to maybe 40 deg. regardless of exterior temp. this is not the 1st time it's done this, any ideas? Cooling fans are running, changing temp setting makes no difference, refer side is facing East, so no afternoon sun

I get the feeling it goes into defrost mode and doesn't come out of it completely.

[dougrainer]

Garry&Gayle wrote:
I have the issue solved, tech hooked up separate battery to refer 12V supply for a week and it worked flawlessly. During this time I removed all battery wires at battery and wire brushed them clean then sprayed with WD40 on reinstalling, been out now for over a week in 95 plus temps and refer is working flawlessly, just as factory tech said "dirty 12V"

Bad wires AT the battery was not your problem. The Power Converter supplies the 12 volt power. I just had a 2020 Jayco that had intermittant control board problems on the Dometic refer. Turned out to be the simplest thing but hard to find. The 12 volt refer supply fuse at the Power center fuses----The 15 amp fuse for the refer the spade terminals on the fuse board were slightly expanded causing the 15 amp fuse spades to not have a normal tight fit. Once we tightened the female spades to clamp tight on the fuse the problem went away. Check all your fuses at the Fuse board. Doug

[Garry_Gayle]

I have the issue solved, tech hooked up separate battery to refer 12V supply for a week and it worked flawlessly. During this time I removed all battery wires at battery and wire brushed them clean then sprayed with WD40 on reinstalling, been out now for over a week in 95 plus temps and refer is working flawlessly, just as factory tech said "dirty 12V"

[Garry_Gayle]

dougrainer wrote:

Garry&Gayle wrote:
The unit is 2012 model and as stated it was working fine for 7-10 days then the warming starts at around 4pm then by the am its 35 deg again, it will hold all day until around 4pm then the warming starts and progressively get worse until the unit is shut down for a day then restarted then it works fine again; this is not the 1st time it has done this. The unit has an additional cooling fan in the back also. A bad cooling unit would not work correctly at all.

You misunderstood what I stated. I did NOT state a BAD Cooling unit, I stated a partially BLOCKED cooling unit. They will operate just fine until the cooling load is demanded from higher outside temps, then they do NOT perform as NEW. After 8 years of use, all those times you parked off level even for 30 minutes or more caused a slow partial block. AND DON'T TELL ME THAT YOU HAVE NEVER OPERATED OFF LEVEL FOR ANY AMOUNT OF TIME. Impossible after 8 years of use, unless it has been parked at the same level site for 8 years. They can only partial block from off level operation or from inadequate of blocked ventilation at the rear CU area. Doug (seen it all in 41 years as an RV Tech)

I won't denie that it's never been run off level, I turned it off last night and it warmed to 60 deg, restarted at 5am and it's now down to 43 deg. with a day time high of 92 deg. This is the part I don't understand is after a shutdown then it starts working again.

[Whiskey_River]

I had that same 1350 unit in a 5th wheel and it did a lot of what you say. When it was real hot out, it could not keep up. It also had 2 computer type fans in the back and the fridge was in a slide. Had a lot of hot air back there.
I plugged in a small 120v fan in the back to move more air up and out of the top vent. I plugged it into one of those on/off wireless remotes that you use to turn outside Christmas lights on & off. That way you can turn it on & off from inside, just point the clicker by the fridge. It did help some, but as others have stated, that double door 1350 fridge is not the most efficient fridge out there.....

[dougrainer]

Garry&Gayle wrote:
The unit is 2012 model and as stated it was working fine for 7-10 days then the warming starts at around 4pm then by the am its 35 deg again, it will hold all day until around 4pm then the warming starts and progressively get worse until the unit is shut down for a day then restarted then it works fine again; this is not the 1st time it has done this. The unit has an additional cooling fan in the back also. A bad cooling unit would not work correctly at all.

You misunderstood what I stated. I did NOT state a BAD Cooling unit, I stated a partially BLOCKED cooling unit. They will operate just fine until the cooling load is demanded from higher outside temps, then they do NOT perform as NEW. After 8 years of use, all those times you parked off level even for 30 minutes or more caused a slow partial block. AND DON'T TELL ME THAT YOU HAVE NEVER OPERATED OFF LEVEL FOR ANY AMOUNT OF TIME. Impossible after 8 years of use, unless it has been parked at the same level site for 8 years. They can only partial block from off level operation or from inadequate of blocked ventilation at the rear CU area. Doug (seen it all in 41 years as an RV Tech)

[Old-Biscuit]

Garry&Gayle wrote:
The unit is 2012 model and as stated it was working fine for 7-10 days then the warming starts at around 4pm then by the am its 35 deg again, it will hold all day until around 4pm then the warming starts and progressively get worse until the unit is shut down for a day then restarted then it works fine again; this is not the 1st time it has done this. The unit has an additional cooling fan in the back also. A bad cooling unit would not work correctly at all.

OK if you say so........

Test the cooling unit and verify YES/NO

[Garry_Gayle]

The unit is 2012 model and as stated it was working fine for 7-10 days then the warming starts at around 4pm then by the am its 35 deg again, it will hold all day until around 4pm then the warming starts and progressively get worse until the unit is shut down for a day then restarted then it works fine again; this is not the 1st time it has done this. The unit has an additional cooling fan in the back also. A bad cooling unit would not work correctly at all.

[dougrainer]

Garry&Gayle wrote:
I have a Dometic RM1350 Refer; when turning on the unit works great whether gas or elec. on setting 4 refer runs about 35 deg. freezer is 0 deg. then around 4 pm it warms to around 40 deg. then by 3 am its back to 35 deg. again. After about a 7 to 14 days at 4 pm it warms to 45 - 50 deg. but then only cools to maybe 40 deg. regardless of exterior temp. this is not the 1st time it's done this, any ideas? Cooling fans are running, changing temp setting makes no difference, refer side is facing East, so no afternoon sun

I get the feeling it goes into defrost mode and doesn't come out of it completely.

Your Model Dometic has no defrost mode. But, if your sig is correct, the unit is about 7 to 8 years old. You may have a partially blocked cooling unit. Your symptoms show that. When hotter temps exist, the CU cannot do a good job. When the sun goes down the CU catches up. But, the 1350 does not have a good history of good cooling even when new. Doug

[Old-Biscuit]

wildtoad wrote:
They make a fan that attaches in the back of the fridge that comes on when the outside temp reaches N degrees and help remove hot air from behind the unit.There is one on mine. They also make a battery powered fan that you can place inside the fridge to better circulate the cooling.

OPs fridge comes with TWO external fans....but thermostat is high
Closes at 149*F and opens at 122*F (+/- 9*F)

That means condenser gets hotter before fans kick on so more heat to remove

Thermostat/fans DC Power comes from DC Terminal Block to Relay with in-line fuse from Relay to thermostat and fans (Red Wire)

If door seals are good, drain line good and cooling unit can cool I would change out the thermostat on the far right condenser fin with one that has lower close/open tempo settings so fans come on earlier

[wildtoad]

They make a fan that attaches in the back of the fridge that comes on when the outside temp reaches N degrees and help remove hot air from behind the unit.There is one on mine. They also make a battery powered fan that you can place inside the fridge to better circulate the cooling.

[Old-Biscuit]

A refrigerator that chases the outside temperature is improperly vented or has a weak cooling unit.

Vented refers to the airflow/draft across backside of fridge cooling unit

To test cooling unit....
Unplug thermistor leads from lower circuit board
Plug a new thermistor in and hang it out the lower vent cover
Run fridge on AC for at least 12 hrs to see if cooling unit can cool....(thermostor hanging outside causes fridge to run continuously)
Place gallon jug of water in food compartment...if after 12 hrs temp is NOT below 43*F then cooling unit is faulty


Couple other things to check first.......
Door seals leaking (dollar bill test)
Food compartment drip tray drain tube......cracked or plug missing from end of tube---
Either will allow warm air to be pulled into food compartment



Service Manual

[Lwiddis]

Supposed to be 96F in Hemet today. If your fridge stays in the 40s I think that’s pretty good.

[agwill]

The hottest part of the day it can not keep up with the external heat. Is the refrigerator on the sunny side of the the trailer? Could use some shade if it is.