Tecmark Plastic Adjustable Spa Heater Pressure Switch 3 Terminals NO/NC Contacts - 4015p

Spa heater pressure switch to suit Compu-Heat spa heaters and others with 3 wires connected to the pressure switch. 3 terminals - NO/NC contacts - to suit low flow indicator light function. Tecmark 4015P adjustable pressure switch 1-5 psi Normally open contact usually used for completion of the control circuit to allow heater operation once there is sufficient pressure Normally closed contact usually only ever used / needed for the connection of an indicator / pilot light to show a 'no flow' error. This would be illuminated when the pump is not running with sufficient water pressure to activate the heater. * Very few heaters use / require this pressure switch version with the 3rd 'normally closed' contact connection - use the alternate pressure switches listed if only 2 wires run to the pressure switch.