Unnecessary F&T trap?

underdog32

I'm having an issue that is causing an entire branch of my supply line to fill with water which causes water hammers and 2 non-functioning radiators. I believe I have tracked the issue to the pictured F&T trap. During a cycle of the boiler very little water escaped this trap. About a half gallon did come out of the vertical pipe that leads to the wet return. I believe the supply is full of water and it's waterlogging the return due to the whole water seeking it's own level thing. I already tore apart the wet return and flushed the heck out of it and verified good flow after I was done, so i'm pretty sure the wet return isn't blocked at this point (though it certainly was at least partially blocked yesterday).

I tried to repair this trap. I took it apart, cleaned it, and even thought I had a successful test of fluid passing through, but it's not functioning. It's many, many decades old.

So according to this, and a few supporting articles I read, a F&T trap is unnecessary when leading directly to the wet return since the fluid in the return forms it's own trap.

https://www.pmmag.com/articles/103158-dan-holohan-what-i-learned-about-steam-traps

So, I believe I can just remove this trap, replace it with a straight pipe and fix the whole problem, but would like a second or third opinion.



For giggles, I snapped a picture of the drain from my kitchen sink that someone actually did, stepped back and said, yep, that'll do. This is on the list to straighten out as well.

EBEBRATT-Ed

It looks like you wouldn't need that trap but need more pictures of the system and a description to be sure

Jamie Hall

Love the sink drain! But a minor caution on the trap -- some -- but not all -- F&T traps have an air vent. If that one does, it may be acting as a vent -- or even the vent -- on that part of the system, and you may need to install a proper vent.

Steamhead

Looks like there are two drips coming into that trap......

AMservices

Is this a single pipe system or a 2 pipe system? 

underdog32

AMservices said:

Is this a single pipe system or a 2 pipe system? 

Two pipe. The picture is on one of two branches of the supply run. The other branch functions 100%

Steamhead said:

Looks like there are two drips coming into that trap......

It continues on from there to another radiator in my garage. It is possible, but not confirmed that it forms a loop with the other branch and gets fed from both sides. The other supply branch enters into a finished ceiling and I haven't mapped it yet. the radiators fed from the left side of that trap seem to work. Only the two fed from the middle of that run don't work, which is the section of pipe I've confirmed as waterlogged.

JUGHNE

Do you have a pumped return or gravity flow?
If that trap is piped into a wet return then no air will get thru it.

Seeing how you have had the trap apart, you might just remove the guts from the trap, the float and needle/seat and the air valve if possible. See what happens.

If you redo your sink drain you should use DWV fittings which have a better radius for water flow. You have sharp turn pressure fittings now. Also eliminate some fittings.

underdog32

Jamie Hall said:

Love the sink drain! But a minor caution on the trap -- some -- but not all -- F&T traps have an air vent. If that one does, it may be acting as a vent -- or even the vent -- on that part of the system, and you may need to install a proper vent.

Thanks. I'll double check, but I didn't see anything that looks like a vent, or hear anything hissing when I drained the water. The entire thing is filled with water too since it can't get out and I don't see any sputtering.

underdog32

JUGHNE said:

Do you have a pumped return or gravity flow?
If that trap is piped into a wet return then no air will get thru it.

Seeing how you have had the trap apart, you might just remove the guts from the trap, the float and needle/seat and the air valve if possible. See what happens.

If you redo your sink drain you should use DWV fittings which have a better radius for water flow. You have sharp turn pressure fittings now. Also eliminate some fittings.

The return is gravity. There are 2 other drops to the wet return from this branch. All 3 have F&T traps. The other two appear to function. I'm guessing they let water through fast enough that it doesn't build up and block the steam. I can try to take the guts out and see if i get any flow.

Yeah, that sink drain is a mess. It's all wrong. I didn't do it. The previous owner of this house was supposedly a contractor...I hope he didn't do it. It looks like they just used whatever spare parts they had laying around. There is yet a 3rd rubber union in the ceiling where it connects to an original steel drain pipe. It's nuts.

AMservices

Air has to get out for steam to get in. 
Can you see any air vents around the boiler or anywhere in the system?

underdog32

JUGHNE said:

Seeing how you have had the trap apart, you might just remove the guts from the trap, the float and needle/seat and the air valve if possible. See what happens.

This, at least temporarily, appears to have restored flow. On this model the thermostatic bellows is a component that is removable from the exterior, so i took it out and cut the bellows so it was always "closed" and fluid could overflow through the air outlet. It's not a permanent fix, but fluid is now moving through the trap. I'll probably try to remove the float/valve assembly tomorrow so water flows out of the bottom where it is supposed to.

underdog32

AMservices said:

Air has to get out for steam to get in. 
Can you see any air vents around the boiler or anywhere in the system?

Yes, there is a big main vent where the radiator return pipes meet the drop to the wet return. It hisses a lot.

AMservices

Ok, maybe some added the f&t because the pressure was getting to high and steam got into the return creating water hammer. didn't know to fix the pressuretrol and figure out why the pressure was getting high. 
If there's only 1 vent, then all the radiators have to be venting through a dry return to that vent. 
You should be able to follow the return lines from each radiator back to a vent. 

EBEBRATT-Ed

He has 3 drips with F & Ts. Those traps are older than dirt someone put them on for a reason. Possibly they are just float traps and need air vents

Steamhead

Some Vapor systems had "non-pressurized wet returns" where each drip to the wet return had a trap. Often there was a Return Trap as well, and all the returns- both dry and wet- fed through it.

Be very careful if you want to ditch that trap. If the wet return is non-pressurized, eliminating just one trap may interfere with the returning water.

underdog32

Steamhead said:

Some Vapor systems had "non-pressurized wet returns" where each drip to the wet return had a trap. Often there was a Return Trap as well, and all the returns- both dry and wet- fed through it.

Be very careful if you want to ditch that trap. If the wet return is non-pressurized, eliminating just one trap may interfere with the returning water.

I'm going to keep an eye on it. I basically removed the trap today by removing the interior mechanisms so water could flow through. Water is flowing well and there are no water hammers or anything. All my prior issues seem resolved and the non-functioning radiators are functioning again and the pipe isn't waterlogged.

The only (negative?) effect I've seen is that the return pipe below that trap now gets hot, which makes sense since steam is now entering it. I will keep an eye on the boiler water level as well. I don't know what pressurized vs non-pressurized returns are and how I can tell the difference.

The trap was definitely bad (non-functioning), and the system is functioning better now, but I agree that some guy probably knew what he was doing 100 years ago when he put that trap on. I will probably order a replacement trap and replace it. I definitely don't know more than the guys who piped that system, and I acknowledge that. My main concern was getting 2 radiators working, and to no longer be woken up in the middle of the night by water hammers.

I do thank everyone who has chimed in on this thread. It has been helpful.

underdog32

this is great. This appears to be exactly everything I tore out of this trap, and exactly the same model. I never thought I'd find something like this.

https://www.statesupply.com/sv1030

JUGHNE

That repair kit does not include a new float.
Are you sure yours is good and remountable.
It should, well, float. Some have a pinhole that fills the float with water.

Also does that F&T have an opening that would vent the air right at the device?
Usually the air is passed into the dry return, above the water line, to be passed thru a separate air vent.

underdog32

JUGHNE said:

That repair kit does not include a new float.
Are you sure yours is good and remountable.
It should, well, float. Some have a pinhole that fills the float with water.

Also does that F&T have an opening that would vent the air right at the device?
Usually the air is passed into the dry return, above the water line, to be passed thru a separate air vent.

I'm not entirely sure the float is ok, but it's 31$ for a new one so i wasn't going to pull the trigger on that yet. I hadn't really considered that the float would be bad though. i'll fill up the sink and toss it in and see what happens. Thanks for the tip.

The venting...I'm thinking that's what the thermostatic bellows does? It lets air out until it gets hot, then expands and closes the hole so the steam stays in?

There is no external vent for sure. It's a sealed unit.

JUGHNE

So the air would leave the trap and travel down the pipe to some other vent.
That drop pipe is dry and never below water?

underdog32

JUGHNE said:

So the air would leave the trap and travel down the pipe to some other vent.
That drop pipe is dry and never below water?

I see your point. The drop pipe goes to the wet return. I don't think there is any way it can possibly be dry ever since it's a solid 10 inches below the entry point to the boiler. There is a check valve stopping backflow, but i don't think it can ever really empty.

This might be why there is a vent installed on one radiator in that loop.

EBEBRATT-Ed

@JUGHNE is right you need a vent down stream of the trap to get the water out. Take the elbow off above the reducer and replace t with a tee. Raise the vent as high as possible with a long nipple

JUGHNE

Could you post a picture of a typical radiator showing both ends and then show the piping of that radiator in the basement and where those 2 pipes connect to the steam and return?

underdog32

JUGHNE said:

Could you post a picture of a typical radiator showing both ends and then show the piping of that radiator in the basement and where those 2 pipes connect to the steam and return?

i'll get a pic of a radiator tomorrow, everyone is asleep in the rooms where they are accessible, but it's pretty standard. Valve on top left, steam trap on bottom right.

Here is about a good of a pic as i can get of the boiler room. It's a peerless 62-14. I could take a pic of the floor piping if needed, but there isn't much to it:



The vertical pipe on the right is gas supply.

The vertical pipe on the left is the drop from the dry return to the wet return. The top of the pipe has the main and only vent on the system other than one radiator with a vent on it.

So, that pipe drops into a tee, into the wet return, directly into a check valve and back into the boiler.

Interestingly, the wet return only services one branch of the loop. I think that drop with the f&t trap that I'm having trouble with serves as the entire drop to the wet return from the other half of the loop.

I'm in complete agreement that it seems illogical that air could escape after getting into the wet return, but at the same time this system was set up by people who know what they were doing 70-80ish years ago. I could potentially put a vent on that drop in the middle of the loop. It wouldn't be hard. I would just change out the elbow with a T and slap a vent on it, but if it's run this way for this many years, I have to think it's not needed?

Steamhead

What vent is on the existing dry return drop near the boiler?

underdog32

Steamhead said:

What vent is on the existing dry return drop near the boiler?

This is the top of that vertical pipe on the left:



This is where that vertical pipe meets the wet return and gets back to the boiler: