A spitting vent usually means water is reaching it: the radiator is pitched wrong and holding condensate, the boiler pressure is set too high, or the boiler is surging and sending wet steam up the risers because of oil or dirt in the water. A failed vent float can spit as well. Replacing the vent without fixing the cause just gives a new vent that spits.
Vents are spitting on every floor since the new boiler went in, skim the oil off it and drop the pressuretrol to 1.5.
Also heard as
- spitting vent
- spitting radiator
Related terms
Main vent
A large-capacity air vent at the end of a steam main that lets air out fast so steam can fill the main.
Rad
Short for radiator, especially the cast iron column or tube radiators of steam and hot water systems.
Priming
Sudden surges that throw slugs of boiler water out with the steam.
Pressuretrol
Shop name for the pressure switch that starts and stops a steam boiler's burner to hold pressure in a set range.