I am having a problem with incomplete defrosting on frt18g4awm. It is a frigidaire top mount. No electronics. It was seen by another tech who replace the defrost timer. When I got the call. The timer had failed and I replace it. I check the the heater and thermostat. The heater was distorted, but still work. I recommended that the heater be change and the customer decline at that time. Anyway make a long story short. The heater eventually failed and I replace it and the thermostat. I place the new heater into the slot on the bottom of the evaporator and secured it.
Problem: After de icing the evaporator 2-3 weeks later the evaporator is completely ice over again. I put the defrost timer into defrost mode and the heater turns on but only melts about half of the ice on the evaporator. When the heater cuts off. There is about a 5 minute pause before the fridge turns back on. I have timed the defrost timer and it runs for 20 minutes.
I have check the freezer door gasket with the dollar bill. They are find. I ask the customer about items freezing in the beer compartment. He stated normaly their is no freezing, but on occasion a item will may freeze in the back. I have check for air leaks and can't find any.
I am open to suggestions