# Internal Bias Heater?



## Fraserjim (Sep 27, 2018)

I am working on my Maytag dryer. It has a thermostat with an “Internal Bias Heater” I know how a thermostat works but am stumped on why one would have an internal heater. Can someone explain? Thanks


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## supers05 (May 23, 2015)

Fraserjim said:


> I am working on my Maytag dryer. It has a thermostat with an “Internal Bias Heater” I know how a thermostat works but am stumped on why one would have an internal heater. Can someone explain? Thanks


It allows the thermostat setpoint to be depressed electrically. The setting on the control panel controls the voltage to the internal heater. The higher the voltage, the lower the trip temperature. 

It is similar to an electronic sensor, or a remote sensing bulb. The remote bulb is more likely to break due to vibrations then stranded wire. 

PS. Old mechanical room thermostats have heaters in them too. They are called anticipaters. They are designed to only bias either the starting or stopping of the equipment, but not both.

Cheers!


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## Fraserjim (Sep 27, 2018)

I think that I understand. Let’s say the thermostat will open at 155. If you want a high temperature dry, the control sends a low voltage to the bias heater so it provides only 10 degrees of heat to the total. The heating element contributes the balance of 145. If you want a low temperature, the control sends a high voltage and it may contribute 100 degrees of heat and the heating element 55 degrees. Is this correct? Thank you.


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