Service techs, plumbers and homeowners alike call the relief valve the pop-off, after the sound and action of a steam safety lifting. The word covers both the 30 psi relief on a hot water boiler and the 15 psi safety on a steam boiler. Saying the pop-off is weeping is common shorthand for a valve that drips because of system pressure problems or debris on the seat.
Customer says the pop-off is spraying water all over the basement, bring a tank and an air pump.
Also heard as
- popoff
- pop valve
- the relief
Related terms
Relief valve
The pressure-relief valve on a hot water boiler, rated in Btu per hour and set at or below the boiler's maximum pressure.
Safety valve
The spring-loaded valve on a steam boiler that pops fully open to vent steam before pressure exceeds the boiler's rating.
Expansion tank
A closed tank with an air cushion that absorbs the expansion of heating water as it warms up.