When your freezer's defrost drain freezes up, it might be because the freezer's temperature is excessively cold, far below 0° Fahrenheit. To troubleshoot this, you can use a tool called a multimeter to measure the resistance changes in the temperature control thermostat as it cools and heats. If the resistance remains the same or if there's no resistance at all, it means your thermostat isn't working properly and you will need to replace it.
You should defrost the drain to ensure it's unblocked. A quick way to do this is by using a turkey baster filled with warm water to melt the ice and break down any blockages. The water should easily flow into the tray near the compressor. If the drain is blocked, even a functional drain strap won't prevent the water from freezing.
If your freezer's defrost drain is freezing up and the temperature of the freezer is well below 0° Fahrenheit, even though the thermistor (temperature sensor) shows suitable resistance changes when tested with a multimeter, it might be due to a malfunctioning control board. This board might be sending uninterrupted voltage to the compressor. To confirm this, inspect the board for any signs of burn marks or a shorted component. If you find any such signs, you may need to replace the control board.
A frozen defrost drain in your freezer could happen if the freezer's temperature is too low, dropping well below 0° Fahrenheit. If tests with a multimeter show the thermistor (temperature sensor) is responding correctly, the issue could lie with the user control and display board. This board might be malfunctioning, which would prevent it from properly controlling the cooling circuit. This means that even when the freezer is cold enough, the cooling doesn't stop as it should.
If your freezer's defrost drain is freezing, it could be because the freezer is too cold, likely much below 0° Fahrenheit. To figure this out, you can use a multimeter to check the temperature sensor. This involves observing changes in resistance as the sensor heats up and cools down. If the resistance remains constant or if there's no resistance, it signifies that the temperature sensor is not working properly. In that case, you'll need to replace it.
If your freezer's defrost drain is freezing over, it could be because the freezer's temperature is way lower than 0° Fahrenheit. In such a case, use a multimeter to check the thermistor, which is a sensor responsible for detecting temperature changes. By measuring the resistance as the sensor cools and warms, you can assess its functionality. If the resistance stays the same or there's no resistance detected, it indicates that the thermistor isn't working properly and should be replaced.
Sometimes, the cause of a frosted-over defrost drain in a freezer could be a faulty or missing drain strap. This small piece, often made of copper or aluminum, is attached to the defrost heater and dips into the defrost drain. When the heater is active, it sends heat down the strap to melt any ice build-up in the drain. However, if this strap is damaged or has fallen off, it can't help to melt the ice, leading to a frosty defrost drain.
If your freezer's defrost drain is freezing up, one reason could be that the freezer's temperature is excessively low—considerably below 0° Fahrenheit. If the thermistor (the temperature sensor) shows correct resistance changes when tested with a multimeter, the problem might be with the main control board. This board could be malfunctioning, continuously sending voltage to the compressor. To verify this, you can check the board for any signs of burn marks or shorted components. If such signs are present, replacement of the board might be necessary.