The Petersen MFG Replacement thermostat will regulate the temperature of your Petersen waterer heaters.
The thermostat comes factory preset at 40 degrees. The temperature can be adjusted by turning the setscrew counter-clockwise to turn the temperature up and clockwise to turn the temperature down.
This Thermostat works well for Customers that want the entire bowl ice-free, although it will use more electricity when set higher than the Factory setting.