Fri Dec 16, 2011 3:53 pm
Apparently that unit has a spst contact that opens when temperature rises to the set point. Thus it's suitable, as is, only for controlling cooling. You could conceivable use it to operate a relay with NC contacts. When the temperature drops the Johnson contacts would open which would de-energize the relay clsoing it's contacts and operating the heater. A bit klugey but workable. There are plenty of controllers out there designed to control heating loads.
