[idahjo]

Is it possible for the 'Bimetal Defrost Thermostat' to malfunction and keep the defrost heater coil "ON" constantly, keeping the compressor running and prreventint the freezer from getting above 15-20 degrees (excluding functioning defrost cycles where it gets above 20 deg)

Thanks

[woodchuck]

NO.

Some defrost systems use a thermostat (a bi-metal switch) to prevent the defrost heater from overheating.

The switch is normally closed.

During a defrost cycle, the defrost heater causes the metal alloy in the switch to warm and as it does it curls back and breaks the circuit.

As the metal cools, it makes a circuit again and the defrost heater starts heating again (as long as the defrost timer is in the defrost cycle).

A defective thermostat can prevent the defrost heater from coming on or allow it to overheat which could result in heat damage or fire.

The defrost timer turns the heater on.

You can remove the evaporator cover and see if the heaters are always on.

[idahjo]

'RIGHT ON' Woodchuck; I pulled the panel and the heater is working (on-off)... so much for that theory.
Now that it is all apart I will be able to report back on your earlier response to me questioning if the evaporator if only partially frosting?

Thanks for the response