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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We've been running the refrigerator's heaters wired directly into an AC outlet for a week and a half, and it is cooling very well---it's typically running about 33-34 degrees in the refrigerator and below 5 degrees in the freezer, occasionally below zero. The eyebrow LED typically shows 17 degrees when the refrigerator's actual temperature is about 33 degrees.
The thermistor's resistance is about 8,650 ohms when the inside temperature is about 33 degrees, and as soon as the refrigerator door is opened it begins to drop. And when a warm sponge is held against the thermistor it's resistance drops rapidly to below 3,000 ohms. Because the spec for this thermistor is approximately 8,000 to 10,000 ohms in ice water, does this not rule out the thermistor?
The diagnostic test revealed what I had suspected, namely that the displayed temperature is dramatically lower than the actual temperature.
I did not test the continuity of the upper display board because: a) I couldn't figure out how to access it (there are a couple of small slots on the right side of the trim, but when I put a small screw driver inside one of them I could see the board moving so I didn't want to pry on that), and b) those tests only indicate continuity or the lack thereof. Because the board's display responds to the control panel's buttons, I assume the continuity tests would not provide any additional information.
Unless someone has another suggestion, I plan to recommend my neighbor look at replacing the lower control board.
The thermistor's resistance is about 8,650 ohms when the inside temperature is about 33 degrees, and as soon as the refrigerator door is opened it begins to drop. And when a warm sponge is held against the thermistor it's resistance drops rapidly to below 3,000 ohms. Because the spec for this thermistor is approximately 8,000 to 10,000 ohms in ice water, does this not rule out the thermistor?
The diagnostic test revealed what I had suspected, namely that the displayed temperature is dramatically lower than the actual temperature.
I did not test the continuity of the upper display board because: a) I couldn't figure out how to access it (there are a couple of small slots on the right side of the trim, but when I put a small screw driver inside one of them I could see the board moving so I didn't want to pry on that), and b) those tests only indicate continuity or the lack thereof. Because the board's display responds to the control panel's buttons, I assume the continuity tests would not provide any additional information.
Unless someone has another suggestion, I plan to recommend my neighbor look at replacing the lower control board.
