The HTC-4 temperature controller is primarily designed for the control of 2 Heat and 2 Cool air-conditioning units. All output relays are voltage free, permitting use on either 240 V or 24 Volt circuitry. Stage switch on points are individually adjustable with their ON/OFF status displayed via LED indicators. The HTC-4 controller is ideally suited for DIN rail mounting in a switchboard, or directly inside the A/C unit if required.