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Refrigerator not cooling properly
Yahoo Message Number: 114592
My 30-year-old Dometic fridge has been a real trooper until recently, when the refrigerator part stopped cooling below 55 degrees or so. The freezer part is working fine. It's the same problem whether on electric or propane. Any ideas what could be wrong?

Fern
Re: Refrigerator not cooling properly
Reply #1 –
Yahoo Message Number: 114593
"the refrigerator part stopped cooling below 55 degrees or so [but] The freezer part is working fine. It's the same problem whether on electric or propane."
 Fern, if the freezer is still working fine, then there's probably nothing fundamentally wrong.
 The balance between the freezer and fridge temperatures is controlled by a small thermal sensor that's clipped onto one of the fins near the upper back part of the refrigerator compartment. If it gets knocked loose, the fridge temperature can get screwy.
 The sensor is pretty inconspicuous, so you may never have noticed it. Look for a white plastic piece with a wire trailing from its bottom. Sliding it upward results in a colder refrigerator compartment; sliding it downward gives a warmer refrigerator. You may have to adjust the thermostat setting (if you fridge has one) after giving it a few hours to stabilize.

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Refrigerator not cooling properly
Reply #2 –
Yahoo Message Number: 114595
"The sensor is pretty inconspicuous, so you may never have noticed it. Look for a white plastic piece with a wire trailing from its bottom."

Hi Andy,
 I have looked to no avail. Is it something that could have gotten knocked off completely? I don't remember finding anything of that description, though.

Thanks for your help!

Fern
Re: Refrigerator not cooling properly
Reply #3 –
Yahoo Message Number: 114599
Quote
"the refrigerator part stopped cooling below 55 degrees or so [but] The freezer part is working fine. It's the same problem whether on electric or propane."
 Fern, if the freezer is still working fine, then there's probably nothing fundamentally wrong.
 The balance between the freezer and fridge temperatures is controlled by a small thermal sensor that's clipped onto one of the fins near the upper back part of the refrigerator compartment. If it gets knocked loose, the fridge temperature can get screwy.
 The sensor is pretty inconspicuous, so you may never have noticed it. Look for a white plastic piece with a wire trailing from its bottom. Sliding it upward results in a colder refrigerator compartment; sliding it downward gives a warmer refrigerator. You may have to adjust the thermostat setting (if you fridge has one) after giving it a few hours to stabilize.

Andy Baird http://www.andybaird.com/travels/
Fern, this might help. It's called a thermister.

Chris
Formerly: 2002 30' IB
Re: Refrigerator not cooling properly
Reply #4 –
Yahoo Message Number: 114602
"I have looked to no avail. Is it something that could have gotten knocked off completely?"
 Unlikely, since it's attached by a wire. If it were really damaged, your freezer probably wouldn't be working.
 For what it's worth, in my 2003 fridge the thermistor is in a skinny white plastic doodad about 3" high that's clipped to the rightmost metal cooling fin at the rear of the refrigerator compartment.
 Yours may not look exactly like mine, since there's a 24-year difference in our refrigerators. But it should be the only thing inside the refrigerator compartment that has a wire attached to it. It may have been knocked loose and be dangling behind the shelves. Look for a white wire coming out of the wall--probably on one side or the other, at the rear. The thermistor will be at the end of it.

Andy Baird http://www.andybaird.com/travels/
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Refrigerator not cooling properly
Reply #5 –
Yahoo Message Number: 114603
Fern, you didn't say what model of frig you have, but 30 years ago is right about the time that Dometic switched to electronic controls. The thermistor is a  temperature variable resistor, only useful for the electronic control boards.  Frig's with mechanical controls would have a copper capillary tube mounted  somewhere on the cooling fins inside, or near the thermostat setting knob. I  seem to remember a white plastic knob with black numbers from 1 to 6, below the  refrigerator door. My SoB was a 1980 Lindy and the Dometic would have been about  your vintage. My source was 'RV Mobile inc.' troubleshooting tips.
Hope that helped, Ron, and a motorhome named Bluebelle, a  '99TKB.

[Non-text portions of this message have been removed]
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Refrigerator not cooling properly
Reply #6 –
Yahoo Message Number: 114604
Quote
The freezer part is working fine. It's the same problem whether on electric or propane. Any ideas what could be wrong?

Fern
Fern, what is the freezer temp? Ours cools easily to 14 - 15 F, and eventually gets to 0F or below. If yours behaves this way, check for a bad fridge door seal.

Steve
2004 FL
2013 Honda Fit
Re: Refrigerator not cooling properly
Reply #7 –
Yahoo Message Number: 114606
"Fern, you didn't say what model of frig you have, but 30 years ago is right about the time that Dometic switched to electronic controls. The thermistor is a temperature variable resistor, only useful for the electronic control boards. Frig's with mechanical controls would have a copper capillary tube mounted somewhere on the cooling fins inside, or near the thermostat setting knob. I seem to remember a white plastic knob with black numbers from 1 to 6, below the refrigerator door.
 Thanks, Ron. Yes, I should have mentioned the model, which is a Dometic RM 760. I checked the RV Mobile site and you are correct, this model was before the switch to electronic controls. I have a brown knob with white numbers from 1 to 7, but adjusting that seems to make no difference on the temp of the fridge compartment.

Fern
Re: Refrigerator not cooling properly
Reply #8 –
Yahoo Message Number: 114607
"Fern, what is the freezer temp? Ours cools easily to 14 - 15 F, and eventually gets to 0F or below. If yours behaves this way, check for a bad fridge door seal."
 The Freezer temp has been around 10-15 F. I've checked the fridge door seal all around and it seems to be fine, near as I can tell. Anything I should look for in particular to indicate it's not?

Thanks for your help, Steve!

Fern
Re: Refrigerator not cooling properly
Reply #9 –
Yahoo Message Number: 114608
Quote
"If yours behaves this way, check for a bad fridge door seal."

"Anything I should look for in particular to indicate it's not?"

Fern
Fern
 The recommended way to check for a bad door seal is to close a fresh dollar bill between the seal and door edge at varying points around the perimiter of the door and then pull the bill out while the door remains closed. If you encounter resistance the seal at that point is okay. If you find an area where there is much less resistance you've got a bad seal and it should be replaced.

Steve S.
Lazy Bones & Jiggs
Steve S.
Lazy Bones & Cedar
2004 30'IB (Island Bed)
Yesterday is History, Tomorrow is a Mystery
Live for the day!
Re: Refrigerator not cooling properly
Reply #10 –
Yahoo Message Number: 114610
Fern,
 Just wondering where you are and what the temperature is .  I'm finding that as we are traveling and in CA now where the last few days it's been 103+ our fridge is having a hard time staying in the 40's..The freezer is working good though, and It doesn't matter if on ac or gas..

Sylvia
'96 30 IB
Re: Refrigerator not cooling properly
Reply #11 –
Yahoo Message Number: 114614
Fern
 Our old LD's RM760 thermostat failed and it had the same symptoms as yours. I replaced it myself and do not remember it being an exceptionally difficult repair.
I used jumpers to bypass the thermostat's contacts and put the refrigerator into full 120VAC cooling to confirm that the thermostat was not working.
BTW, it was only months after making this repair that it developed that dreaded ammonia smell, requiring the replacement of the refrigerator. Don't throw too much money at this elderly refrigerator; it is way past its expected lifespan.

Larry
2001 MB
* Not to be confused with Larry W (3000 of my posts are actually from expert Larry W due to Yahoo transition mis-step)
Re: Refrigerator not cooling properly
Reply #12 –
Yahoo Message Number: 114637
"Just wondering where you are and what the temperature is."
 Sylvia, the temp here in Virginia has been in the upper 80s/low 90s. But a few weeks ago we had several days in the 100s, and my fridge did fine then at keeping things cool, I just had to turn it up a bit. So there's definitely something wrong now. Thanks for bringing up the possibility of it being a factor, though.

Fern
Re: Refrigerator not cooling properly
Reply #13 –
Yahoo Message Number: 114638
"The recommended way to check for a bad door seal is to close a fresh dollar bill between the seal and door edge at varying points around the perimiter of the door and then pull the bill out while the door remains closed. If you encounter resistance the seal at that point is okay."

Thanks, Steve. I'll check that out.

Fern
Re: Refrigerator not cooling properly
Reply #14 –
Yahoo Message Number: 114639
"Our old LD's RM760 thermostat failed and it had the same symptoms as yours. I replaced it myself and do not remember it being an exceptionally difficult repair."
 I'm planning on having a RV repair guy take a look at it. I'll mention this to him.
 "Don't throw too much money at this elderly refrigerator; it is way past its expected lifespan."
 It's been cooling amazingly well up until now just a few days ago. I'm hoping I won't need to replace the whole thing, but I guess we'll see.

Thanks for your help, Larry.

Fern