Straight through pattern F&T Trap (e.g Watts nee Illinois 6G)

archibald tuttle

I'm getting slow fill on convectors in a two pipe residential system. I'm not getting any steam out of the condensate return tank vent but I am suspecting that I might be passing some steam through the end of the mainline vent/traps (two mains) which are illinois 6Gs. They haven't been serviced in 50 years so I can't really complain except that the only service kits I can find cost as much as a new trap. We don't discuss prices here at the wall but i'm in the middle of converting as much of this house to radiant as possible so i can abandon the steam. It's a really neat system but two steam traps like that are going to cost me as much as a entry level condensing boiler.

And I can find plenty of Hoffman style H patterned traps as leftover industrial stock, but the drop from inlet to outlet is way more than I can handle. I need a clost to straight through pattern like the 6G. Those are much harder to find.

I didn't have big enough wrenches to pull the piping just downstream of the traps to check for steam which I believe Dan counsels is the only real way to check how tight they are since an F&T trap doesn't exhibit significant temp. drop even when operating correctly.

so the mains are filling and a few of what were always the best radiators. don't aaaask me why but some always better than others not measurably by pipe friction or any other metric i can figure out. and i would pull the trap heads off all of 'em and get the same results.

so the problem is, we're talking 40' 2" mains with, i would suspect, moderate condensate load. all the rads are 2 piped and trapped to the return, and not too many long feeds and they are only 3/4" which, beside the condensing in the main itself would be the only other source. so i'm unsure if that is enough condensate for a bucket trap and how imprtant a thermstatic vent for the main is with all the rad themostatic vents relatively close to the main piping. system is operating under 1 PSI so i can't replace it with a disc trap. I could put a 3/4" straight pattern rad style thermostatic trap, but since the main will be carrying steam and staying hot it is going to have to back up condensate and cool for a while before the trap would open. current piping would allow me to make about a 3' 3/4" lead pipe dropped off the main to act as a trap. maybe that is enough.

well, there's a novel for the morning. just like going to church.

thanks,

brian

MilanD

I wonder if you can pipe in a p trap like "u" with a B&J crossover to serve as a 6G....

Jamie Hall

MilanD said:

I wonder if you can pipe in a p trap like "u" with a B&J crossover to serve as a 6G....

Sounds like a plan. If there is any drop at all between the steam main that will work splendidly. Your U drop needs to be enough so that steam won't blow through it -- 28 inches for each pound of pressure you are running at cutout.

Sailah

The 6G aren't really repairable. We just replace with an inline F&T. They aren't that expensive relatively. You can call me Monday and I'll set you up.

archibald tuttle

sailah, will reach out on monday is your number associated with your identity.

milan and jamie, of course, smaht idea. what if I put in two tees in the 3/4" on either side of a thermostatic trap so the condensate drops into the first tee, air during startup displaces along the old course and then through the thermostatic trap along the original straightthrough trajectory to vent air then the next tee would bring the trap into the return, the weir of which can be going on a pipewidth below the trap so the trap fills and the steam pressure in the main (1/2 lbs, give or take) pushes the water in to the open to air return. so I just have to make the trap say 36" deep just in case it runs up to a pound, say, it still doesn't haven't the pressure to completely displace the water in the trap. and even if i have a radiator trap that leaks a bit into the return i'll never have much pressure in the return. its open at the condensate tank so unless it condenses before traveling 40 feet back to the boiler i'd see it. but even if the pressure in the return and the main were equal, i've still got a little drop so it trains. and/or, what is the B&J "crossover" of which you speak, is it what i have just describe where the B&J is a straight pattern thermostatic trap or . . . .?

Jamie Hall

A crossover trap is just an ordinary radiator trap. The usual piping is to up a short nipple or so from a steam main, then 90 and a suitable nipple into the inlet of the trap, then take the outlet straight down to the return line with another nipple.

MilanD

Yep. Radiator trap. I mentioned B&J bc of venting capacity.

Yes tee will work exactly as you described. T trap on top, and 28" "U" per 1 psi below. Install a drain at the bottom of that U as crud and sludge will collect and you want to have a good clean out port. Or a dead leg with a cap. Either in the center of the center of that U. Then, for servicing down the road, just replacing of the guts will be needed. Those are, depending on the manufacturer, at the most a couple of Andrew Jacksons.