Thermostat, Solid State, 120 volt
Line terminal is 120v hot input. The middle two terminals are neutral and as they are not switched it doesn't matter if they are line or load as long as a neutral is applied. Load terminal is the 120v hot output when the t-stat calls for heat. This unit is meant to run pilot duty and will only handle about an amp. This must be used to control relays to switch the actual load. Do not wire directly to heater.