What kind of trap is this?

aairheatcool

The main turns down to go through the wall and at the bottom of the elbow a line goes to this trap and exhaust directly into the return. We are having hammering in this return. I can’t find any info on this trap. Has anyone seen this kind? Is it thermostatic or just float? Outlet stays hot and hammering starts around 1.5 psi

EBEBRATT-Ed

Looks like a boiler return trap but from your piping description I would replace it with an F & T sounds like it is just dripping the main. Is this going into a dry or wet return? (has to be dry)

Steamhead

Either a Barnes & Jones or Sterling F&T (Float & Thermostatic) trap. When we run into these, we like to upgrade to a Sarco-type F&T which is much easier to repair.

aairheatcool

Yes it’s dripping the main, it’s dripping into a horizontal return that is above the water line. But not by much.The water line is 28” from basement floor. That puts it in the horizontal pipe. The drip connects to that return about 39” from the floor. The hammering is happing where the drip and return meet. Somewhere in that area. The circles on the pic is where the hammer sound like it’s happening. Is it possible that it’s a vacuum problem from the hot water coming from the trap or is more than likely the trap is bypassing steam, you can hear it surging through there.

aairheatcool

EBEBRATT-Ed

@aairheatcool

You need to drop that return so it is under the water line. That's why it hammers. Drop straight down from the trap and just lower the horizontal pipe. Chances are the original boiler had a higher water line

aairheatcool

Thanks for the help, our company just started working at this building. the old maintenance man had passed away last year and he always maintained this boiler, I believe the current boiler is the third replacement. And lots of modifications over the years. It’s been interesting starting it up.