Thermal Relief Valve | Pump Protector Valve | High Temperature Safety Valve
These pressure washer pump protectors are commonly called thermal relief valves, as they are designed to protect the pump from high temperatures within the pump head. Leaving a trigger gun closed while the pressure washer is on is called 'running in bypass.' If left in bypass for extended periods of time (more than 2-3 minutes!) the water within the pump head heats up, which can cause damage and failure of the pump seals and valves. Thermal relief valves open at 145 degrees or 190 degrees, to protect the high pressure pump from damage.