Cleaning the coils on rooftop units may seem mundane, but it’s an important job that pays off for your customers in more efficient operation and longer living equipment. And, any job that’s worth ...

Knowing the sequence of operation for this type of starting relay can help you diagnose, confirm, or rule out certain service problems. Potential starting relays consist of a high resistance coil and ...

Relays are electromechanical devices that use a magnetic solenoid to actual a switch. When current is passed through the solenoid coil, it produces a magnetic field. The magnetic field is strengthened ...

David Yuill received funding from the American Society of Heating, Refrigerating, and Air-conditioning Engineers to conduct this study, under Research Project 1705. He is affiliated with ASHRAE. I ...