Quirky Steam balancing problem

Steamhead (in transit)

next thing to check for is marginal pitch on the slow steam main. Maybe there's a water pocket forming somewhere- look for a broken pipe hanger.

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Tom Hopkins

Quirky Steam balancing problem

I have a one pipe steam system with the following dimensions:

Left side main 49' X 2 1/2"
Right side main 45' X 2 1/2"

The left side has a connected EDR of 192 and the right side is 98 EDR.

Both mains are well insulated. The left side is vented with one Gorton #2 and two Hoffman 175s. The right side is vented with one Gorton #2. The problem is that the left side vents much slower than the right even though is has much more venting. Also, the rad at the end of the main on the left side gets very little (if any) steam and it's closest to the t-stat.

I have enclosed a drawing of the system.

Notice that there are three large rads on the left side which are close to the boiler and I wonder if they're stealing steam?

Do I need more venting on the left side to balance with the right side?
I have not been able to find a pro in my area that has been able to help.



Also, there are two plugs in the mid part of the left side main. Could I put
another vent in one of these to quicken the venting?

Any suggestions would be appreciated.

Steamhead (in transit)

That behavior doesn't make sense

there has to be a problem somewhere.

How about posting a pic of the near-boiler piping?

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Jeff_100

Here's a pic

We had the boiler replaced last year. The old one was a very large Weil McClain. The new one is MUCH smaller. I had them install a dropped header.
Even with the old boiler, the balancing problem was the same. I did find
that some of the large upstairs rads. had lost their insulation on the risers. I opened the floor and dropped insulation into the wall chambers that house
the risers. Now the floors in those areas don't get hot and the heat stays in the pipes.

Any thoughts?

Phil_17

Are the two mains fed from separate risers

My old system (recently replaced) had a setup where the boiler had two tappings, and each one was directly connected to my mains (no header connecting them, no equalizer, and no hartford loop either: check valve). One of the mains just never got good steam. The other would heat quickly and quietly but the "bad" one acted much like what you are talking about.

When we replaced the boiler a couple months ago, the guys put in a new MST with proper header, equalizer, and hartford loop... The cold main heats like a champ now, and I actually have been able to get some balance in the venting. This piping stuff really does work like Dan's book says it should :-)

gerry gill

you may have

the closer radiators stealing steam, just as you think..we call that runout robbery when the runouts and radiators steal the steam from the main before it gets to the end.. test this by closing the closer radiators and seeing what happens..if it works better, put tiny vents on those radiators and big vents on the far end.

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Tom Hopkins

The pitch in the mains seems correct - no broken staps. I took Gerry Gill's suggestion and shut off the biggest rad (42 edr) and the rad at the end came
right up to full heat and steam got the end of both mains at about the same
time. The vent on this big rad is not adustable...I wonder if I should get an
adjustable vent and set it at its lowest setting?

Steamhead (in transit)

If someone put a big vent

on that rad in an attempt to make it heat faster before the main vents were upgraded, that might be causing the problem now. What vent is on that rad?

Try an adjustable vent like a Hoffman #1A, this will let you fine-tune it.

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Tom Hopkins

Currently there is a Maid - o - mist non adjustable vent (#6 I think). I'll try
the adjustable and set it low.

Thanks