B&J Big Mouth vent clearance

bklynick

I'd like to replace an existing G1 with a B&J Big Mouth vent.
Any advice on the best way to install without busting open the ceiling?
Will a shorter nipple do the trick or is there a minimum height requirement off the main?

See attached photo.


Some background for reference:
- 30 ft 2" front main (3 risers), vent will be placed here.
- rear main only 4 feet no vent

Thanks!

JohnNY

A shorter nipple will do the trick. Be careful of your A dimension.

bklynick

Thanks John - now that I'm looking at it more closely - can I just forego the nipple and screw right into the tee or do I need some height to it?

ethicalpaul

If it were me, I'd put a hole right in that ceiling

acwagner

A best practice is to have the vent as high above the main as possible. Having more height helps protect the vent from being damaged. The general guideline is 6 to 10 inches above the main, or whatever height space allows.

If your existing Gorton is doing fine at that height, then you might be OK just putting the bigmouth as high up as the ceiling allows.

But, I agree with @ethicalpaul that going into the ceiling is the best solution.

mikeg2015

Big mouth does burp out a bit if steam before it closes. You may want a small piece of stainless steel sheet plate above it.