Why is the outlet of the Barnes & Jones BJ-3BM “Big Mouth” vent threaded?

jsavage

I bought some Big Mouth vents and I’m curious why the outlet is threaded. Is it to handle any water that might spit out?

Thanks!

PS I did search for this answer, but feel free to just provide a link if this question has been answered before. Thanks!

EBEBRATT-Ed

They make the big mouth out of a trap body and trap bodies are threaded. + you can pipe the outlet to a drain to catch any leak

jsavage

Awesome, thank you!

JUGHNE

Just so you know, the Big Mouth vents do not have a float.
So is any water gets to it it will spill out.

I have put these up as high as possible. In school house class room they are on a 4' riser. I added a ball valve under them in the event something happens. I 90ed out the back and nipple down a couple of inches so any steam vapor might not cook the wall. So far so good.

Steamhead

Also, so they can be used as crossover traps.

jsavage

@Steamhead What is a crossover trap?

Steamhead

On a Vapor system, we often find radiator traps piped between the end of the steam main and the dry return. This does the same thing as a main vent- helps air get out of the steam main quickly- but routes the air into the dry return so it will leave the system at the central venting point.