F & T sticking?

ratio

Had this trap stick, I believe, a few days ago. It's on the outlet of a shell and tube HX (has a vacuum breaker installed), I noticed that there wasn't any ΔT on the water side. I banged on it to try and loosen the other inlet plug but it wouldn't come out. A few minutes later I noticed that it was working again.

Do these occasionally stick? Is that a sign of something going on? It's not too old; the HX failed a number of years ago & this why longer went in at the same time. Should I have a rebuild kit/spare on hand?

EBEBRATT-Ed

Being on an HX is harder usage than a typical heating job. I would rebuild it.

Make sure the vacuum breaker works. I like to use a check valve instead of a vacuum breaker. With an HX I like the vac breaker installed at the trap inlet on a long nipple or pipe to raise it up high to keep it dry. The trap should be sized with a 2:1 or 3:1 safety factor depending on the type of load on the hx.

I like to drop the trap inlet below the hx as far as possible. The more height the better. Most say 12" minimum I like as much as I can get.

depending on the load sometimes two traps in parallel work better

Sailah

That Hoffman doesn't look very new to me, we rebuilt a lot of those.

You can take it apart but be aware the gasket will most likely be ruined so you need a new one onhand.

The float mechanism can get hung up inside the body, look for wear on the float or binding in the mechanism. Also dirt and debris can obstruct the seat. I've had this happen all the time, fix a trap then 2 weeks later it's blowing. Having a strainer and regular blown downs helps.

@EBEBRATT-Ed tip about running them in parallel is a good one. I've seen some nice HX run like that and the redundancy is appreciated.

ratio

I guess it might be original, for some reason I thought it had been changed out when the new HX went in c. 2013. Here's a pic of the location, on the tail of a B&G SU65-2. The vac breaker is on an arm maybe 8" up from an aux tapping on the back of the shell, I believe it's installed per mfgr's recommendations. It flows in the right direction only, although it might be kinda stiff—I don't really know what a good one feels like.

The load is a hydronic heating loop, pneumatic steam valve on a reset controller, about 180° max for a handful of old Nesbitt fancoils.

The tenants are 100% responsible for maintenance, but experience has shown me that they aren't willing to do anything more than emergency repairs. As this isn't a safety issue, I guess I'll just get ready to rebuild it.

Thanks for your help, @EBEBRATT-Ed , @Sailah

Sailah

That trap is probably 50 years old based on label in my experience and doesn't look like it was rebuilt as the new Hoffmans are ITT and have been for awhile, I don't know when they left Indy but it was a long time ago

EBEBRATT-Ed

Plus I believe if it was rebuilt the whole cover on those comes off and gets replaced and that one hasen't been changed

Sailah

That's 100% correct, that trap may have been NOS. the FT56 is a faceplate swap. Isolate trap, remove 4 bolts, clean the gasket face, bolt new one on. Less than 5 minute job.

ratio

Ha! That's pretty old. The original building went in in the late 40's/early 50's, then an addition, then this addition. I'm guessing 60s-70s. It isn't 80s construction.