Adding a Main Vent

icarmany

This is my first winter in a 1923 house with a two pipe steam system. I believe this was originally a Broomell system based on the name stamped on the older fittings. (I still haven't figured out how the quintuple valves are supposed to work) I've been going through the system and fixing various things. Next up is the main vents.

There are 3 mains coming off the header, two of which form a loop about 100' in length. The first thing I did was replace the vents on the main loop and the return. This was pretty straightforward. However, on that 3rd main coming off the header, is a 30' foot run that terminates into a wet return with no vent. (Note that there do not appear to be traps in this system at the end of the mains, only one between a dry and wet return.)



This 30' leg has 3 radiators running off it, one of which has a varivent. I'm thinking the varivent is improper and should be removed and plugged (and was probably installed because of lack of mains venting), and a mains vent should be added around past where the last takeoff is. The 30' leg heats slower than the 100' loop.

You can see from the photo that there is about a foot of ~3" OD pipe and then an elbow that reduces into a ~2.5" wet return. Unfortunately the plugged T is before the last takeoff. Not sure if that was a vent that was plugged ages ago before the pipe was painted.

So what i'm thinking is drilling and tapping the side of that reducing elbow for 1/4" pipe and then putting 3 elbows in to get the 1/4" up to the ceiling for a B&J Big Mouth vent. Does that seem right? From what I understand 1/4" is adequate for 1 vent, and coming off the side of the elbow rather than the top is acceptable. Alternatively I can try to tap the top of the pipe, which seems more risky, or hire a plumber to replace the elbow with another fitting.

Thoughts? This forum and Dan's books has been a great resource. Thanks in advance.

JUGHNE

The 2 mains that loop around are they connected together in the center, and do they both return to the header or return as a drop to the wet return at the boiler?

icarmany

You can see here where the two mains connect together in the center, and then head down to the wet return and travel 40' back to the boiler.

The ceiling mounted radiator is a bit of a head scratcher as well. I guess it's an old condensing radiator based on Dan's articles of the Broomell system. They've got those quintuple valves that don't seem to do anything. Also visible is a Hoffman 1A vent (I assume this was incorrectly installed), what I believe to be an antique Broomell trap at the far right, and the big mouth i recently installed.

EBEBRATT-Ed

@icarmany

drilling and tapping the reducing elbow is fine but I would drill and tap the 3 x 1 1/2"??? tee to keep the vent away from the end of the main

Gordo

@icarmany
Welcome to this forum!
You mentioned Broomell quintuple radiator valves in your post above.
Below is a YouTube video you may find useful.
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https://youtu.be/rj_jK1WTJ1M

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JUGHNE

The steam main on the left is parallel flow sloping down to the right.
Is the main on the right connected to it sloped down to the boiler header?

Can you show us the boiler piping that would show those connections?

icarmany

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EBEBRATT-Ed said:

@icarmany

drilling and tapping the reducing elbow is fine but I would drill and tap the 3 x 1 1/2"??? tee to keep the vent away from the end of the main

Using that tee for the vent is OK even though it feeds a radiator? What's the concern with putting the vent at the end of the main?

@Gordo

Thanks, your videos have been very useful. I've already watched a bunch. I wanted to redo the pressuretrol plumbing on my weil mclain model 80 like you've done in your video straight out the top, but I chickened out when torqueing the plugs. Ended up doing it like this (admittedly less elegant) to allow for cleaning.



@JUGHNE

Hopefully this photo answers your questions. The main on the left and the right form a loop that originates from the header.




Perhaps tomorrow i'll make a diagram of the whole system so that we're all on the same page. I think it would be helpful for my own understanding. Thanks in advance.

Gordo

Thank you!

On the subject of the pressure control tree, I understand why you left those plugs alone.
They are really only easily accessible when the boiler jacket is off during installation.

The 1/2" drip pocket is "factory approved", but if you want to add brass pigtails, I would turn that first 1/2" tee up so the water isn't trapped there and also in the pigtails.
I may be wrong, but you might be "double trapped".
I would put the gauges on 1/4" tees, jut out with a nipple and a 90 just under the p-trols and vaporstats so they can be removed and the pigtails occasionally checked for blockages.

I hope I haven't run my mouth too much.