Dometic RM1350 Refer

[sgreene_1963]

I have a Dometic RM1350 Refer in my Alpine 5th wheel and it has been giving me some intermittent problems since last July. The unit cools to the correct temperature when first started and will hold it for days sitting in my driveway. We do run the refer while driving to our destination to keep the unit cold. (I will say that the RV is NOT level front to back sitting in my driveway....it has only been during my research to discover what was happening with the refer that I realized the importance of the RV being level.)

The last three trips the unit will be cold on setup at the campsite but has over a period of time (usually within a day or so) will warm up and show somewhere between 45-50 degrees on the display. (A separate thermometer inside the refrigerator side shows a similar temp.) It has not, up to this point at least, gone above 50 degrees. The RV is completely level on the campsite.

I've had the RV at the dealership twice now and the unit has performed flawlessly for them. We've not had the unit out this season but will be going out over Easter. The dealership has had it doing other service for about 3 weeks and still no issues.

My fear of course is that the cooling unit is bad. That's the most expensive repair option but the dealership is telling me that the thermistor and control board test good and are not likely to work intermittently. They are suggesting, and I fear they are correct, that the cooling unit is only partially blocked but somehow clears itself when turned off.

I was wondering if anyone else had experienced similar issues and what was done to resolve the problem.

Thanks.

[Old-Biscuit]

laknox wrote:
Not sure this would work for this situation, but some people "burp" their fridge by pulling it out, and turning it upside down for a while, then trying it again. Most seem to report (or so I've read here) that this will work...for a while. "A while" being from weeks to years. YMMV...

Something else to try, if you can, and that's to move the thermistor on the cooling fin it's attached to force a lower temp. Don't ask me which way it needs to move, I can't remember.

Lyle

Relocating thermistor on fin only affects temps in fridges that do NOT have adjustable temp settings on control panel. Ones that use a factory preset thermostat---auto t-stat.

And 'burping' fridge.......once you go to the trouble of removing it just go ahead and FIX it.
Band-aid approaches as just that....a temporary attempt at fixing an issue that ends up hurting when you have to redo---rip the band-aid off. :B

[laknox]

Not sure this would work for this situation, but some people "burp" their fridge by pulling it out, and turning it upside down for a while, then trying it again. Most seem to report (or so I've read here) that this will work...for a while. "A while" being from weeks to years. YMMV...

Something else to try, if you can, and that's to move the thermistor on the cooling fin it's attached to force a lower temp. Don't ask me which way it needs to move, I can't remember.

Lyle

[sgreene_1963]

I have been in touch with the dealer almost daily and they have it plugged in (AC) and it is supposedly running. No failures that they have told me about and are telling me they check it twice a day. Who really knows but I choose to believe them given what I know of the dealer.

I did buy a OEM thermistor to run the check that you mentioned but won't know until we go out over Easter weekend in a couple of weeks. I still believe you're right about the blockage given what is happening. I am willing to spend $40 to see if it is the thermistor since everything else is more expensive........especially pulling the refer and installing a new cooling unit. This will be our first trip since winterizing the unit last October.

Just an FYI, it was both compartments warming up....not just the refrigerator side. The freezer always cold enough to keep ices and frozen foods but ice cream was soft.

Thanks again.......I appreciate your input.

[Old-Biscuit]

sgreene_1963 wrote:
Thank you for your feedback on this issue. I will try the suggestion with the termistor just to rule this out as a possibility but believe you're correct on the clogged cooling unit. It is ironic that the refer has been at the dealership (service) since mid-February and still not failed. It did the same thing last fall when I had it there then for them to diagnose the issue.

Rig at dealer since mid-Feb .....have they been running fridge since them or just ran it for a day and called it good?

12 hrs. of operation fridge may initially cool down properly (freezer & food section) but food section can gradually increase in temps 24 to 48 hrs. later due to blockage.

So IF fridge has NOT been in service 2 days or more then cooling unit has NOT be really tested as to whether or not it is good

[sgreene_1963]

Thank you for your feedback on this issue. I will try the suggestion with the termistor just to rule this out as a possibility but believe you're correct on the clogged cooling unit. It is ironic that the refer has been at the dealership (service) since mid-February and still not failed. It did the same thing last fall when I had it there then for them to diagnose the issue.

[Old-Biscuit]

Is freezer section functioning correctly----items remain frozen?

Food section temps slowly increasing over time.


Cooling unit is clogging.
Off-level operation while 'stationary' interrupts gravity flow of coolant solution. This interruption causes 'overheating' condition which turn the sodium chromate (anti-rust inhibitor) to crystallize which plates out on the inside of tubing. This plating out is permanent and Accumulative.
Just 20 minutes of off-level operation can cause this issue.

Some low cost items that can cause lack of cooling:
Food section drip pan drain hose....no plug (check valve) in end of hose OR hose is cracked/broken (warm air gets pulled into food section

Fans not functioning in outside compartment IF your fridge has fans.
Fridge has a 'roof vent' then most likely no fans (fridge in slide NEEDS fans)



Usually you can unplug thermistor and force fridge into continuous cooling mode
This can NOT be done on your RM1350. Thermstor 'failure' shutd down fridge cooling
You can cause fridge to force cool but this requires another thermistor
You unplug OEM thermstor leads on control board and plug new thermstor leads onto board then hang that new thermistor out the lower access vent so that is is sensing warm air making fridge run and run and run.
With a thermometer in a glass of water on self in food section-----temp should be below 43*F after 12 hrs.
BUT best to test for 24-48 hrs when a slow warming condition has been issue.

So buy another OEM thermsitor and test cooling unit (run it on AC element for test)
OR take it back to dealer and have them run the force cooling test.

Cheaper to buy another thermistor an do test yourself.

[YC_1]

If the refer is in a slide the fans may be acting up.

If the drain tube is cracked it will allow warm air into the refer. Cracked drain tube is quite common.