Wet return sizing

Ray_B25

is there a chart for sizing the wet return of a steam boiler? One of our guys came across a 287,000 btu boiler with a 1” copper wet return. There was water spitting out of two gorton# 2 vents. The vapor stat was set to 16 and I had him turn it down to 11 with a 8 oz differential the spiting stoped but the 1” wet return doesn’t seem right to me. Also having him clock the meter to be sure it’s not over fired.
I would appreciate any advice

mattmia2

400,000 btu/hr of steam is roughly 1 gpm of condensate so I think your issues are elsewhere unless the returns are clogged.

pecmsg

please post pictures of the near boiler piping.

EBEBRATT-Ed

287,000 boiler output is only about .56 gallons/ min=34 gallons/hour.

Burnham heating helper says 1" is good for 900EDR=216,000 btu

1 1/4" =1530 EDR=367,200 btu

mattmia2

https://forum.heatinghelp.com/discussion/comment/1843248#Comment_1843248

Is that for a wet return or a 2 pipe dry return where it needs to carry condensate and air?

Dave in QCA

One other thing to consider that is not in this generalized for a return, it does not mention the length. If it is very long, and if there are quite a few 90s in the pathway, that will reduce the capacity. If they are straight runs with few turns, it should be OK

By comparison, I was involved in advising on the rebuild of an 1880 2 pipe system with vertical pipe radiators aa few years ago. The total system load of 610 EDR, equally split between 2 mains and two returns that were installed with 1: soft copper, insulated and buried below the concrete basement floor. In this case the 1" wet returns have been performing just fine.

EBEBRATT-Ed

@mattmia2

Wet. Thats what the op said he had.

Mad Dog_2

I'd go with 1 1/4 copper on this one.. Mad Dog