Square-headed Valve for System Balancing

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Old 09-29-10, 04:45 PM
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Square-headed Valve for System Balancing

My older system has 1" black-steel NPT valves for flow balancing. The have a 5/8" bronze square stem that you turn with a wrench. I don't know if you'd call them a plug or a ball valve. There are no stops - they turn 360 deg (which isn't an important feature, of course).

Can anybody suggest a source for these valves or for suitable replacements?

Most modern ball valves aren't recommended for throttling service (not sure why). And, globe valves don't have a full throat. Gate valves are out.
 
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Old 09-30-10, 04:36 PM
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Square head

If they still work why not still uae them, if they dont already have a mark that tells you where they are [closed or open], make your own marks, that will make it easier to play, they probably last another 50 years.
Sid
 
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Old 09-30-10, 05:19 PM
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There usually are marks... at least on the ones that I've seen... not many though.

Why the concern about globe valves not having a full throat? You are throttling them anyhow? and the good quality ones have ample throats on them.

My biggest objection to using ball valves is the noise factor... when they are mostly open, fine... but when you get to the point of actually throttling, they get noisy... that, and the fact that 95% of the throttling range is in the last 10% of the valve 'travel', they are VERY difficult to set properly.

Why not take a look at something like the B&G "Circuit Setter" ?
 
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Old 09-30-10, 05:36 PM
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The marks are there on the stem - no problem. But one of my balancing valves has a packing leak, even after tightening it.

Some of my balancing valves are throttled, but most are wide open - but maybe a globe valve would be OK for the one that is leaking.

I looked at the B&G circuit setters. I think they may be the answer to the maiden's prayer.

I think my old square-stem, steel balancing valves may be totally obsolete. I believe they may be plug valves, not ball - but whatever. They are in the basement, and noise hasn't been a problem.
 
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Old 09-30-10, 06:27 PM
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Circuit setters are the best. Globe valves are a good balancing valve but very high in EFP. A 1-1/4" iron globe valve is equal to 39 ft of pipe when wide open.
 
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Old 09-30-10, 07:18 PM
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1-1/4" iron globe valve is equal to 39 ft of pipe when wide open.
I guess what that means is that just by adding the valve, you've already throttled a bit. As long as you plan for the fact by proper pump selection shouldn't be a problem though.

Circuit Setters are nice cuz you have a 'reference' point to set them.
 
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