SPST 50A Start Relay This Start Relay is used to start a single package unit, or a complete air conditioning installation The Trane RLY3372 Start Relay is the ideal choice for your air conditioning and heating needs The RLY3372 is a small form, single-pole, two-throw start relay with a screw-in terminal block and end bell Relays are designed to operate over extended periods of time with little maintenance and monitoring The RLY3372 is a single-pole, single throw (SPST) contactor designed for use as a start relay to operate equipment such as air conditioners and refrigeration compressors The Trane RLY3372 50A SPST Remote Start Relay is a replacement relay to replace the failed or damaged existing relay This can be adjusted using an adjustment screw on the relay body SPST 50A Start Relay A relay contains an electromagnet that is activated by an electrical current to mechanically change the state of the relay This relay can be used as a replacement relay or to add more relays to your system The most common form of relay is a switch that can be operated by remote control Compatible with the following systems: Relay, SPST, 50A Relays are electromechanical switching devices that control, monitor, or select electrical currents, circuits, or electrical equipment The Trane Start Relay is part of your air conditioning and heating system, which has a motor that spins inside an air handler and pushes the cold air through ductwork to the rest of the home This could be called something else, like a blower fan or an evaporator, but for our purposes we will refer to it as a start relay When airflow falls below this level, the relay sends an electrical signal to turn on the equipment It is powered by line voltage, and is installed between the electrical service and the air handler, where it is wired in series with the line voltage power supply SPST 50A Start Relay, For use with Trane model: ACK40AC030C1, CK40AC030C1, CKH9AC030C1, CTH9AC030C4 The Start Relay senses when the airflow reaches a predetermined minimum level