steam main vents

jtompkins

I have 2 main vents about 12inchs from the elbow at the end of the pipe. They are on a 6 inch riser and i replaced them with new hoffman 45. They dont seem to work. The boiler is set at .75 psi +1. The house has 5 radiators on the main floor and 2 small ones on the second floor. There seems to be excess steam and spitting coming out of the second floor . The main Floor air vents are set at 4 and the second floor are at 1. How can i stop this?

Jamie Hall

What kind of vents are the ones that are spitting? Make? Model?

Also, have you checked that those radiator inlet valves are fully open, that the radiators are pitched correctly, and that all the pipes feeding the radiators are pitched correctly?

jtompkins

First i had Hoffman 40 now there is hoffman 1a set at 1. The radiators are pitched leaning to the pipe. The service valve does open and close. I have not checked the pitch on the main pipes. How much pitch should the main pipes have? With the main vents should i use Hoffman 4Aor 45?

KC_Jones

jtompkins said:

With the main vents should i use Hoffman 4Aor 45?

Most likely neither as they don't have a lot of capacity. Main vents need to be sized based on length and diameter of the mains. Do you know how long and what pipe size your mains are?

jtompkins

The pipe to the left 30' the one to the right is 35' . The pipe is 2-1/2 thickbut i will double check that when i get home

KC_Jones

If you measure ~2 3/8" OD then that is 2" pipe. For mains that length and size I'd say you need a Gorton #2 on each one.