Refrigerator Won't Cool Below 40 Degrees
A couple of weeks ago my neighbor purchased an older RV with a Dometic RM1350 refrigerator that holds the refrigerator temperature at 40 degrees as verified by a number of different thermometers. I'm ...
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I am still convinced the main problem is that the heaters are cycling on and off at too high of a temperature. Permit me to provide some additional information:
A couple of days ago I had my neighbor run the refrigerator on LP for about six hours. (He was low on LP so didn't want to run out during the night and have the refer heat up and spoil his food.) After the six hours the fins had some ice on them, which soon disappeared after switching to AC.
The next day I wired the heaters directly into the 120 AC outlet and ran it that way with the refrigerator turned off, so all of the controls and wiring of the refer were bypassed. (Consequently, the external fans did not run at all.) I did not feel comfortable doing this overnight (especially because it's not my RV), so we only ran it during the day when we could monitor it. After about 7 or 8 hours we checked the fins and they had some ice on them.
I plugged the refrigerator into my Kill-A-Watt meter and that is when I discovered that the heaters are cycling on and off because sometimes the refrigerator is drawing 380-400 watts, and at other times it's not drawing anything.
Something is telling the heaters to cycle on and off, but we haven't sat there all day watching the Kill-A-Watt meter to see if this happens at random intervals or on a regular cycle.
In summary:
1) The heaters are cycling on and off and maintain the refrigerator at a near constant 40 degrees whether during the day or at night
2) The eyebrow temperature display shows 32 degrees when in fact the actual temperature is 40 degrees
3) The thermistor's resistance is within spec
4) When the thermistor is immersed in ice cold water the eyebrow display shows 25 degrees
5) If the door has been open for a while, the eyebrow display shows a much higher temperature
All of this leads me to conclude that the refrigerator's controls falsely "think" the inside temperature is 32 degrees when in fact it is 40 degrees, and therefor the controls cycle the heaters on and off to maintain that temperature.
A couple of days ago I had my neighbor run the refrigerator on LP for about six hours. (He was low on LP so didn't want to run out during the night and have the refer heat up and spoil his food.) After the six hours the fins had some ice on them, which soon disappeared after switching to AC.
The next day I wired the heaters directly into the 120 AC outlet and ran it that way with the refrigerator turned off, so all of the controls and wiring of the refer were bypassed. (Consequently, the external fans did not run at all.) I did not feel comfortable doing this overnight (especially because it's not my RV), so we only ran it during the day when we could monitor it. After about 7 or 8 hours we checked the fins and they had some ice on them.
I plugged the refrigerator into my Kill-A-Watt meter and that is when I discovered that the heaters are cycling on and off because sometimes the refrigerator is drawing 380-400 watts, and at other times it's not drawing anything.
Something is telling the heaters to cycle on and off, but we haven't sat there all day watching the Kill-A-Watt meter to see if this happens at random intervals or on a regular cycle.
In summary:
1) The heaters are cycling on and off and maintain the refrigerator at a near constant 40 degrees whether during the day or at night
2) The eyebrow temperature display shows 32 degrees when in fact the actual temperature is 40 degrees
3) The thermistor's resistance is within spec
4) When the thermistor is immersed in ice cold water the eyebrow display shows 25 degrees
5) If the door has been open for a while, the eyebrow display shows a much higher temperature
All of this leads me to conclude that the refrigerator's controls falsely "think" the inside temperature is 32 degrees when in fact it is 40 degrees, and therefor the controls cycle the heaters on and off to maintain that temperature.
