why the F&T trap

Al Letellier_9

Good question....typically their are no traps on the return lines after the rad traps. It usually goes directly into a receiver. Probably another case of " gee...I don't know what's wrong with this system, let's try this and see if it works......" Could be a valid reason, but without seeing the whole system, it would be tough to guess as to why this configuration. How is the system operating?

Ray Binder

F&T trap

Im working on a two pipe steam system in a large mansion. There are sixty radiators. The radiators all have 1/2" Sarco H traps on them.The return for the radiators is seperate from the return on the main. The radiator return mains are high up about ten inches below the level of the steam mains. when they get into the boiler room, (there are three of them) They have an air vent on a nipple, and then they go into a 3/4 F&T trap. from there they go into a common pipe, and yet another F&T trap (2 inch) with a vent before it. from there it goes into a boiler feed pump.
The smaller F&T traps are not new stuff. they have been there a long time. The 2 inch trap looks like it was installed with the new boiler five years ago. ( the infamous master trap?) Why the F&T traps when the radiators have traps on them, and these return lines only serve the radiators? The mains return in a seperate pipe. Two of the mains combine and feed a condensate pump in the boiler room that pumps into the boiler feed pump, the third runs along the floor and into the hartford loop at the boiler

Ken_40

Where is Steamhead when you need him?

I believe I know the answer and it lies in blown traps being "masked" by more traps, installed when someone decided it too troublesome to find the blown units on a system that large.

I'm in Hilton Head playing golf and my LAOSH is home in VT where today's high may be zero...

Ray Binder

The system is operating, with some apartments too hot, a few radiators cold, and water hammer in one radiator where a service man installed an air vent. I guess he saw the plug on the radiator and figured a vent should go there. My problem is that this is not new work. those F&T traps with their vents have been there at least 25 years or more. Somebody had something in mind and I think it was well thought out. Not a bandaid. I just wish I could find out what he had in mind. The sarco radiator traps are not original. I think they were installed at the time the F&T traps were. My guess its a vapor system that was converted years ago, and then further messed with when the new boiler was installed about five years ago. I could sure use some help on this one.

Patrick Linhardt, \"Linhardt's Field Guide to Ste

blown trap theory

Hi Rainman,

I agree with Ken's blown trap theory, add traps at the mains instead of fixing the real problem. All those traps are upsetting the natural flow of the air and condensate, double traps take away the differential that traps need to operate correctly.

I saw this situation a few months ago, F&T's on the return lines of already trapped radiators with plugs where vents should be. The story was the air vents were removed by an oldtimer years ago. He manually vented the air once, and the system worked fine until the next boiler install. Not your typical scenario. The HO showed me a tote sheet of gas usage for the last 25 years or so, low usage for the size house and location. I'm still scratching my head on that one.

Best regards, Pat

Steamhead (in transit)

Been out working

what's "golf"?

Some Vapor systems, notably Webster, did use F&T traps to drip steam mains into wet returns and vent them into dry returns. They called this the "no-pressure return". But that's the closest thing I know of to your situation.

My guess is just like Ken and Pat say, someone stuck those F&T traps onto the returns because steam was reaching the boiler-feed pump. They either didn't know to look for bad radiator traps or didn't care.

The proper thing to do here is remove the extra F&T traps and fix the rad traps. Also see if the system can run on gravity return, without the boiler-feed and condensate pumps. If so, remove them and you'll reduce the operating and maintenance costs.

"Steamhead"

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gerry gill

yup, i was wondering

why it wasn't gravity also..

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Patrick Linhardt, \"Linhardt's Field Guide to Ste

no pressure wet return

Hi Frank,

I have a brass tag from a Webster 0023A that shows the "Typical Diagram for the Type R System", piping diagram that is. It is one of my most cherished antiquities. It shows two wet return lines. One is labeled, "NO PRESSURE WET RETURN", the other, "PRESSURE WET RETURN".

Patrick Linhardt, \"Linhardt's Field Guide to Ste

no pressure wet return

Hi Frank,

I have a brass tag from a Webster 0023A that shows the "Typical Diagram for the Type R System", piping diagram that is. It is one of my most cherished antiquities. It shows two wet return lines. One is labeled, "NO PRESSURE WET RETURN", the other, "PRESSURE WET RETURN".

The difference, I'm sure you know but I'll describe for others, is the same as Dimension "A" (pressure wet return) and Dimension "B" (no pressure wet return), LAOSH pages 23-34 or so, other places too. I just referenced that from the pink edition, that color is a keeper, who would want to take it.

The F&T trap removes the operating steam pressure less the friction loss from helping push the condensate back in the boiler. That's why the boiler return trap was necessary on two pipe coal-fired. The Pressure wet return was connected on the boiler side of the outbound check valve.

I've attached a photo of the brass tag.

Best regards, Pat

JackEnnisMartin

steam traps

Hello
I just have to know when you say supplies a condensate return pump --- you really mean a condesate tank, correct?
If not I would sit down and really think about what the trap is doing for the system.I am sure you will see my point if no tank exists. In the meantime turn the system off; connect a collection point on the two inch trap and see if the trap is blowing steam if so you have established the problem for good.
All the best and I hope it works out.
Jack Ennis Martin

Ray Binder

F&T traps

Thanks for the help guys. The first thing Im going to do is replace the radiator traps. All of them. and all the vents in the basement.At that point I should have no steam in the dry returns in the basement. Then Ill see what I can do without. Thanks again Rainman.

Patrick Linhardt, \"Linhardt's Field Guide to Ste

upon further review

Hi Rainman,

I was looking at your pics and post again, because it doesn't make sense. Unless, you have your supply and return mains switched. The first pic reminded me of the end of a steam main trap, like need to be installed in an old gravity system when you add a boiler feed tank. How long has the system been on a boiler feed? Do the other mains that combine and then go into a condensate pump have traps on them? If they are the steam mains and don't have traps, then there would be steam coming out the vent of the condensate pump. Just a thought before you replace all those radiator traps.

Best regards, Pat