Let’s talk about how to Identify a Single Pole and Double Pole thermostat and also the difference between the two.
A Single Pole thermostat will have 2 wires. A line and a load. The line being the building power coming to the thermostat and the load being the power going to the heater. For Double Pole thermostats, you will have 4 wires. 2 lines and 2 loads.
The difference between these 2 types is that Single Pole thermostats don’t have a “TRUE OFF” setting. The thermostat still receives power even if the heater is not running. It only breaks the power line on one side of your heater, so if the room temperature drops below the minimum temperature of the thermostat, the heater will still turn on. As you can see, the control knob will have a low temperature setting without an “OFF” position.
Whereas Double Pole thermostats will have a “Positive OFF” setting. All power to the heater is interrupted. The control knob will have an “OFF” Position, so regardless of room temp, the heater will never turn on.
