Refrigerator Won't Cool Below 40 Degrees

Thank you Old-Biscuit for providing the three corrections.

In reply to your comments:

a) The two outside fans seem to be working properly because they cycle on and off as the temperature of the condenser fins changes in response to the heaters turning on and off

b) My neighbor had borrowed a number of thermometers from other neighbors---at one time he had 5 different thermometers in there! I had him fill a small plastic bottle with water and poke a hole in the cap through which he inserted the shaft of a small stem thermometer, and this we placed on the top shelf of the refrigerator under the thermistor. Prior to doing this we checked the accuracy of that thermometer by placing its stem in a beaker full of ice cold water, ensuring it read close to 32 degrees.

c) Regarding the "automatic cooling unit cycling system": I had read about that in the manual and concluded it shouldn't be a factor at this point in time because we've turned the refrigerator off a number of times in the last couple of days to test various components, and that cycle isn't initiated until 60 hours after the refer is turned on

d) This afternoon I asked him to switch the refer to LP and run it that way for 24 hours. I'll check back with him tomorrow afternoon and report back what I find.

e) Regarding air leaks: One of the freezer doors isn't sealing properly as evidenced by the dollar bill test, but at this point I don't think it is the main culprit. I did not look closely at the drip tray drain tube---I'll try to remember to do that tomorrow---but I do recall seeing the check valve.

f) I did not perform the upper display panel tests, but I'll take a look tomorrow to see how long the refrigerator doors would need to be open to do so---we're trying to keep the doors closed as much as possible because he needs to keep the food as cold as possible.

After chasing all the supposed fixes for 2 years to make my RM1350 operate properly I cured the problem!!!

It's called Samsung RT21M6213SG/AA







I'll admit this cure is not cheap.

BUT------ Freezer keeps ice cream hard.

Refrigerator has not gone above 35 degrees.


Went from 13.5 cu. ft. to 21.2 cu. ft.


If anyone is interested the RM1350 with all the fans and duct work are out in the shed.



C.B.

Great advice:

Fans must be working. Remove the upper outside panel and look inside. If you can't peek down then use a camera to see if there are some fans. There should be a snap thermistor that controls them. You might be able to trace the wires down to find it. A simple alligator clip will bypass it for testing.

The other thing is the vent tubes. If they are cracked they let in warm air. If you need to replace them you might be able to slide the refer forward just a bit after finding all the hidden screws holding it in place. Front and back of course.

listen to old biscuit, he knows his stuff. one other thing ,it takes about 12hrs or more for these frigs to get cold.

1st off........
Display is actual temp of food compartment...not set temp
2nd....
Unplugging the thermistor in THAT model will not cause continuous cooling..it will shut fridge down until thermistor is plugged back in or faulty one replaced
3rd...
Moving thermistor location will NOT have much if any affect on temps because fridge has an 'adjustable thermostat' ----1-5 settings



OP
Are the fans in outside compartment functioning...running/moving air?
How are you measuring temp in food compartment?

Fridge has an 'automatic cooling unit cycling system'
Shuts down heating cycle every 48 hours to 'defrost' fins in food compartment

Air Leaks
Door seals......if not fully sealing air leaks in causing warmer then normal temps
Drip tray drain hose 'check valve' if missing in end of drain hose or if drain hose is cracked.air leaks in causing warmer then normal temps


Upper display panel testing continuity
There are 4 contacts on end of circuit board
Temp set point....continuity between 1 & 4
Auto/Gas..........continuity between 3 & 4
On/Off............continuity between 2 & 4
(see pg. 21 in Service Manual Link)

Service Manual RM1350

1. Control Boards NEVER cause cooling performance problems
2. As another poster stated, a 4 door refer in a slide room requires that a extra upper 12 volt fan be installed to force the hot air out the top door.
3. ALL your parameters you tested are to spec. The only thing you have NOT stated is HOW you test the interior temp. The ONLY valid way is a glass of water after 24 hours
4. The FIN temp will be 10 degrees colder than the interior temp----26 degree fins 36 degree interior temp
5. Moving the Thermister does NOTHING for a adjustable refer tstat.
6. 120 volt voltage can make a difference on performance. BELOW 115 volts will impact Heat element performance. ALWAYS use LP for 24 hours to verify performance of the refer if Line voltage is low or suspect. Doug

I installed 4 muffin fans on a thermostat in the top vent that would turn on around 100° and that did did help.

According to the mobile tech that improved the performance of our slide-mounted refer, airflow in a slide-mounted refer is quite often the problem. Our installation allowed the hot air to circulate around the "box" instead of going from the lower vents, past the heat exchanger, and out the top vents. He installed card board baffles that kept the hot air away from the top and sides of the "box". Made a big improvement.

Unplug the thermistor...should go into continuous cooling...no cycling. If this gets your temps cold enough then find a location for the thermistor (near the fins, not on) that gets you the temp you want with it plugged in.

Adjust the temp sensor bulb located on the far right fin inside the refer near the top. There are instructions all over the place about how to move it. BTW, the display shows set temp not actual temp.