Mechanical t-stat with bulb inserted in the coil with CI set at 38/39 and a 14-15 differential will solve the freeze up problems. You are sensing coil temp. A CI of 38 coil should be equal to 38 air temp. The differential is based on a 10 degree TD. A 15 degree differential= a 23 degree coil=33 degree air temp for cut out. Most Freeze up issues are, like you said, doors being proped open or gaskets. That being said, I prefer an A419 with a defrost clock. The electronic stats seem to be more accurate. Plus you can set the ASD to prevent short cycling of the pump.
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