Steam Sizing Help- To drip or not to drip!

Boston Standard_2

I've got a customer who required a full one-pipe, near-boiler repipe. After this work, we found some noise in the system, and saw that a previous contractor had relocated 2 steam radiators. These radiators are spitting & banging. 1 radiator is about 40 sq. ft. EDR, the other is about 15 sq. ft. EDR. Both are fed with a single 1" supply line that the contractor repiped, and left backpitched. He had suggested installing an individual return line (to handle the condensate) for these two radiators and to correct the pitch where he drilled through a main support beam.

The connection off the steam main is a 2x1 Cast Iron Tee, but is completely level- no pitch. I'm concerned about this because I'll never get pitch if it didn't start with any! I would normally recommend cutting appropriate fittings into the steam main and feeding each radiator individually, allowing them to drain their own condensate back to the steam main, and back to the dry return. Doing that is a whole bunch more work, which I'm not against, I'm just looking for options (such as setting up a return off the existing piping etc...) Thanks- Joe
PS- Notice the photo: The backpitched line comes through the beam at the top right of the photo, then feeds 2 radiators where the pitch is good (even a bit too much)

Mad Dog_2

A drip can only help there

but may not do the trick 100%. With The Steam..its either all or nothing. madDog

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Brad White_203

By my book

those two radiators (55 EDR) would require a 1-1/4" feed, together and the single 25 EDR radiator alone would require a 1" feed and top that out. So, there is one limitation right there. If that arrangement travels over ten feet, I would go up a size to 1-1/2"

Only if one dripped the run could you go down one size, but you are at the maximum even then, for that pipe size.

Counterflow is a bit tough because even if you drop a drip "sooner" in the piping, what goes forward to the radiators is still under-sized.

If it were my decision, I would re-pipe the larger radiator separately using a 1-1/4" minimum feed and leave the 1" to serve the smaller (15 EDR) radiator.

If the distance is still an issue, running the ends of both runs past their respective radiators then dropping individually to a common wet return would also help. (I do not know the logistics of where the two radiators are relative to one-another, so this is just an ideal suggestion).

I would also vent the ends of those runs, with vents held back the usual distance from the ends, with a Gorton #1, to take the burden off of the radiators' vents, before dropping to that wet return.

Bottom line, pipe is too small and pitch is also not in your favor. Split and drip.


My $0.02

Brad

bob young

DRIP

MAYBE YOU WANT TO DROP BELOW THE MAIN JOIST & DRIP EVERYTHING