Main vent capacity vs tap size

Wcurtis

if an additional main tap is added, does this allow more venting capacity because I feel limited due to a single tap.

62' of 2.5" pipe, currently have 1 B@J Bigmouth and system appears to work fine.

Tried 2 Bigmouths then 1 Bigmouth and 1Hoffman 75 with no improvements on either combination.

Jamie Hall

What pressure are you seeing at the boiler as the system is coming up to steaming and filling the system? It's very likely that one Big Mouth is ample, but the way to check is to look at the pressure. If it rises very little, or comes up no a few ounces and then sits there until the system is pretty well full of steam — all the radiators hot — your venting is fine.

JUGHNE

What is the pipe size tap is the vent connected to? 3/4…1/2 etc?

Steamhead

And, how long between the steam entering the main at the boiler end, and when it reaches the vent?

Wcurtis

3/4" tap

Wcurtis

pipe size and length was used to determine vent from "Greening Steam" main vent chart for Hoffman 75 and B@J chart for Bigmouth..all based on 1oz column in each chart.

Jamie Hall

3/4 inch tap is more than enough!

Wcurtis

Appreciate the feedback, if I add an additional 3/4" tap will this increase the venting capability?

Jamie Hall

No, You could put a very impressive antler on that singe tap and still do fine.

Neild5

3/4 tap can easily support 2 Big Mouths.