Hello Im new at trailering and need some help. I bought WW 5th wheel 2008, and my fridge is not always cold. Freezer works great. Ok, when i bought the trailer the fridge was cold. when i brought it home fridge cold warm. saw the hanging thermostate so i put it back on the last fin, where i thought it went. no luck. disconnected the thermostat and fridge works great. bought a new thermostat and put it in. fridge still worked fine, but when i got home from work fridge was warm. thought maybe i lost power, so i powered down and powered up. next morning fridge is great. same thing again when i got home. no power loss on AC. im using a standard electical extension. i tried moving the new thermostat up and down, but the fridge still giving me same issues. Can i just disconnect the thermostat or will that just be a temporary fix. Please help, i want to enjoy my long awaited trailer.Thanks,ErnieChino, CA

You can disconnect the thermostat but you willl have a freezer that runs constantly if you do. Ammonia type refrigerators are notoriously weak and at their worst when empty. I suspect the heat of the day is raising the temp in the fridge. Take a couple of gallons of water and place those in the fridge and see if it holds temperature better. If all you have is air in the frig when you open the door the inside temp will drop drastically. The water will act as a heat sink and help maintain the temperature.

It take a long time to cool down an RV fridge - common mistake by newbies is to open the fridge door often to check temp noting that freezer is cold and fridge isn't. Be patient .. if your super curious put a remote thermometer inside fridge. Consider putting in a water jug or something for thermal mass - easier to test for cold by grabbing the jug after 8 hours or so.When I go camping I turn the fridge on the night before .. I put in the food (pre-cooled in stick house fridge) in the morning.

Sloop Smitten wrote:You can disconnect the thermostat but you willl have a freezer that runs constantly if you do. Ammonia type refrigerators are notoriously weak and at their worst when empty. I suspect the heat of the day is raising the temp in the fridge. Take a couple of gallons of water and place those in the fridge and see if it holds temperature better. If all you have is air in the frig when you open the door the inside temp will drop drastically. The water will act as a heat sink and help maintain the temperature.True. Chasing temps in an empty fridge will drive you crazy. In addition to Sloop Smitten's comments, place your thermometer in a container of water, move the thermistor UP on the fin for colder, and consider installing some small computer type fans to move air up the vent stack.

I have been buying a 24 pack of 16 oz water bottles and freezing them in the deep freeze at home. Then like others have said load the fridge with all cold items. Then I pack any area in the freezer that is not full with frozen water bottles and the same in the fridge. This makes a huge difference. If in really hot weather you can grab a couple frozen ones from the freezer and put them in the fridge and put the melted ones in the freezer at night. Works great. By the way this was not my idea, I stole if from someone here on the forum!Besides those melting bottles of ice make for a great drink on a hot summer day!

Sloop Smitten wrote:You can disconnect the thermostat but you willl have a freezer that runs constantly if you do. Ammonia type refrigerators are notoriously weak and at their worst when empty. I suspect the heat of the day is raising the temp in the fridge. Take a couple of gallons of water and place those in the fridge and see if it holds temperature better. If all you have is air in the frig when you open the door the inside temp will drop drastically. The water will act as a heat sink and help maintain the temperature.The Freezer has nothing to do with the temp Thermister. The Thermister senses the temp of the evaporator fins, nothing else. If you have an AUTO temp refer (no adjustable tstat) then moving the thermistor up and down only changes the refer temp 4 to 5 degrees. If NOT cooling below 40 degrees, then he has a operational problem. Doug

Dometic Fridge | Good Sam Community

Old-Biscuit
Explorer III
Jul 02, 2014
A short......
erniebpk
Explorer
Jul 02, 2014
My fridge blew the 3 amp fuse again without me messing with anything. I had unplug the thermostat in the morning n the temp dropped to 45 degrees. What do you think that might be causing the fuse to blow n cut the power to the fridge
Old-Biscuit
Explorer III
Jul 01, 2014
Unplugging the thermistor (thermostat is built in) causes fridge to run continuously, non stop, no temp regulation. Leaving it unplugged the food section will start freezing up.

Take that 'new' thermistor while it is unplugged and place the tip in a glass of ice water...more ice than water. With ice water temp at 32*F measure the resistance at the end of leads. 8,000 to 10,000 ohms thermistor is GOOD.

So test that new thermistor.
dougrainer
Nomad
Jul 01, 2014
A "quick" guess is a bad marginal cooling unit. You need to wire the 120 element direct to 120 power for 24 hours and see how the refer performs. 41 degrees is NOT good. Doug
erniebpk
Explorer
Jul 01, 2014
More updates on my Dometic fridge. This morning i checked my fridge at 0530 hrs n it was at 70 degrees. I unplugged the thermostat from the back of the fridge inside the little black plastic box. At 1300 hrs the fridge is at 45 degrees. I just replaced the thermostat a week ago. What do u think the problem is?

Ernie.
Old-Biscuit
Explorer III
Jun 30, 2014
erniebpk wrote:
How do i fix a draft problem if i have one and the insufient air flow problem?

As a test.......

Stick a big box fan next to lower vent opening (vent removed) blowing air into fridge outside compartment then check temps Am and again afternoon.

IF fridge temps remain low then you need to install a couple of 12V DC pan-cake fans in the upper area just below upper vent.

If temps still vary....low to high. Probably blockage is occurring in cooling unit
erniebpk
Explorer
Jun 30, 2014
How do i fix a draft problem if i have one and the insufient air flow problem?
Old-Biscuit
Explorer III
Jun 30, 2014
Moving the 'thermistor' will NOT correct a 40*F change in food section temps (only good for 6*-8*F change)

Overnight/early morning......temp 41*F but come late afternoon when it's hot outside temp goes up to 80*F.
You have a 'draft' problem...insufficient air flow across cooling unit from lower vent thru upper vent
OR your cooling unit is experiencing blockage inside cooling unit
erniebpk
Explorer
Jun 29, 2014
Update on my fridge. After fixing everything i checked the fridge this morning at 0900 CA time and the fridge was at 41 degrees. CA time. Today at 1500 hours the fridge is now at 80 degrees. Its about 90 degrees and the tralier side of the fridge is partially in the sun. I have about 4 coke cans inside the fridge to use as cold reference. I moved the thermonstate down about a half inch or less to see if the. Fridge would get a little colder. Going to try and move it back up to where it was.
dougrainer
Nomad
Jun 28, 2014
Sloop Smitten wrote:
The Freezer has nothing to do with the temp Thermister.

Since the refirgerator fins are cooled by the freezer the thermistor has everything to do with the freezer. Once the thermistor senses a certain temperatue in the frig it cuts power to the freezer to maintain the frig temperature. Temperatures in the frig are dependent on the temp in the freezer.

From a RV tech with 35 years experience. There are 2 sections of a RV absorbsion Cooling unit. The Top section tubes which is the freezer which is the FIRST section of tubes that get sub cold. Then the tubes go down a few more inches and contac the lower section where the Evap fins are. THAT section is controlled by the Tstat. This is one thing, novices do NOT understand especially when they purchase a used RV. The seller has the refer ON, and shows how cold the freezer is and the inexperienced buyer assumes the refer is functioning. BUT, a BAD cooling unit will Freeze the freezer but not the lower section, and then the novice finds out he was had to the tune of over a $1000 to fix the refer. The evap fins will be 10 degrees cooler than the refer. So, if the refer is 36 degrees the fins are 26 degrees and THAT temp is what the tstat responds too.
Doug

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