Freezer evaporator keeps building with ice not allowing the refrigerator to cool. I've replaced the defrost sensor twice. Everything works fine for about 2 months then the same thing happens. Could it be the heater?
Answer Hello John,
The defrost heater WR51X10055 can be the problem. You can test this with a resistance meter (ohm meter). Be sure when testing that the wires are dis-connected and tap on the heater while the meter is touching the terminals in case the element is broken and touching inside the glass tube. One good indication that the element has failed is that the glass tube will be blackened.
What should the ohm resistance be on heater tube? I checked it and and it read 21.4
AP3183311 is your heater number
Answer Hello Ed,
As per the spec sheet for your unit, the resistance should be 18O, +/- 10%. Be sure when you test the heater assembly to tap on the assembly while testing for proper results. If tapping on it causes the reading to drop to no contact, the element has burned in to and is contacting intermittently.
I have issues with defrost, The heater has resistance and the t-stat was closed when I checked while the coils was frozen over, I assume this unit does not have a traditional defrost timer and is incorporated the the main control board?
What else can the problem be?
The unit does use the main control board to go through the defrost. Before you replace the board though, this unit also incorporates a defrost thermistor. The thermistor sits at the top of the evaporator coil and is a white bullet looking piece with 2 white wires going into it. The resistance of the thermistor at 0 degrees should be 42.2K ohms of resistance. If not within 10 percent of this resistance then the thermistor is bad and would need to be replaced.