Tecmark 3902 Pressure Switch

It is made with 1/8 inch NPT plastic threading, two terminals for spade connectors, and is adjustable from 1-5 lbs. This Pentair MasterTemp Water Pressure Switch replacement is a factory original replacement heater part that works with all MasterTemp heaters. The water pressure switch functions by turning off the burner if the water flow is interrupted. If the water flow is restricted, the water pressure switch may prevent the burner from firing and cause the Service System light to go on. If the light remains on after the filter has been serviced, have a qualified service technician check the system.