How to Adjust an 859M Thermostat

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The King 859M thermostat, an older thermostat model that uses a knob, adjusts easily. Unlike many modern thermostats, there is no "auto" mode. You can only turn the thermostat on or off. The thermostat is easy to adjust. However, the thermostat may not reach the desired temperature and may require further adjustment. Do not attempt to adjust the wiring of the 859M thermostat unless you have the instruction manual with a wiring guide. Faulty wiring can cause electrocution or start a fire.


Step 1

Examine the 859M thermostat. Locate the number that describes the temperature you wish to turn the heat to.

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Step 2

Move the dial right or left until the black line of the thermostat knob aligns with the appropriate temperature.

Step 3

Adjust the temperature as necessary. Turn the dial left to lower the temperature. Turn the dial right to raise the temperature.

Step 4

Power off the heat. Turn the dial left until it will not move any longer.


To best preserve electricity, keep the thermostat turned under 70 degrees.

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