what are these square-head valves?

Plumbob

Our old system has these square-head valves that are closed by turning them 90o with a wrench. I have been looking on the web and I have read about gate, ball and globe valves, but these don't look like anything shown on web pages.

What are these valves, and are they good for balancing (not just shutoff) purposes? Given that they are 30 years old, should I ask for them to be replaced during new boiler installation, and if so, what would be best? I am not sure that balancing will ever be needed, the square head valves were always wide open, but it would be nice to have the capability.

Many thanks,

Carl PE

Sounds like

a plug valve.

yes, you can use them for balancing. you can even take them apart and re-build 'em. however, if they're that old, I'd say they've probably had enough. get yourself some nice shiny new ball valves and you won't have to worry.

J.C.A._3

Sounds to me....

Like someone decided to use gascocks for shut-offs and/or balancing valves. If the system is being replaced, get rid of em'.A nice full port ball valve will do the trick.Chris

Weezbo

there are Thousands of valves:)

narrowing the manufactuter would help in the information input. there are valves that have the handel taken off expressly for the Keen Home owner with a wrench Not to fornicate with them:)if you see a round thing that looks like a small steering wheel made out of iron for example ...that would be the valve handel.(are these large 4"?)small 1/2" ? could be you are looking at check valves....or some flow valve...twistin on em with a wrench might not be a particular good idea.are these on a steam system?.........put the wrench Down:)

Dale

Square Head Cocks

Those are plug valves used for balancing normally found on multi loop older steel piped forced circulation hot water systems. Very common on 3 to 6 unit apts. The idea was to get the boiler running and when hot measure the return temp on each of the runs then close the valves on the hotter runs ( least hydraulic resistance ) until the return flowing temp was about the same in all return runs. Most of the ones I see are just full open. The square head is there since the idea was that these would only need to be adjusted once with a wrench and then not touched again. If this was my system I would figure out what is connect to each, not too hard if you close them which is sometimes not possible since they haven't been closed since 1930 and then consider zone valves if you want greater temp control. If I was changing the boiler I would at least replace the square heads with modern circuit setters so you could have isolation and measured flow.

RPG_2

would you use..

Would you use a gate valve? I don't like those ball valves (with straight handles) because they are too easy to move.

Which kind is better for flow control (balancing)?

I greatly appreciate your help.

Carl PE

Don't

Do NOT use a gate valve for balancing. They are for shutoff only.

use a ball or globe valve for balancing.

Steamhead

Bell & Gossett

recommended the use of these valves when changing old gravity systems to forced circulation, to balance the system if needed.

J.C.A._3

Steamhead,

Most of the valves I've seen described are "barrel" type valves. Would/should they be used as balancing valves? Seems to me they would be noisy on something with big flow.
Just thinking back to the systems I saw them on, and most were big pipe and HUGE pumps. Seems I always remember a "whine" associated with them. If your on the 3rd floor, no problem, if you living right above them, it'll make you go looking for a weeping hose bib or leaky toilet.Chris

Steamhead

I've never taken one apart

have to do that next time we remove one!

oil-2-4-6-gas

.

definetly a plug valve we see them all the time on gas lines from 1-1/2 up to 8 inch i'm sure they make them bigger but i haven't seen any --they are common on larger B&G heating circ's ---used for balancing ---- to balance a system you can use globe valves plug valves or balancing valves -----you shouldn't use ball valves the flow eventually will wear away the body and the handles are too easy to move

Paul Bock_2

B&G balance valves

I've seen the plug stlye head on valves from 1/2" to at least 4". They are a bear to turn if the haven't been excercised for a decade or two.

The ones I have taken apart are a tapered plug type, with the elongated opening.

My guess is that if you try to move these, you will get an oportunity to replace them.

Paul

larry_9

Plug valaves

If you loosen up the nut on the bottom and tap it up you will find out that you can move these valaves. That is why they use them as shut offs and or balancing valves, back in the old days.

Larry

ScottMP

Those valves

Where very common on older systems in our area and where used for balancing. Old steel pipe systems.

Scott

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Brad White_2

Neither, IMHO

I like Tour and Andersson or equivalent Armstrong or Oventropp balancing valves. These have built-in T&P ports and have 4 turns open to closed (1440 degrees of turning) in the smaller sizes most of us use, and 8 turns on larger sizes.

Compare this to a ball valve which has 90 degrees, and only the last 45 degrees or so does the work.

The T&A type valves are a little more money, but well spent, especially on low flow systems where water flow management is critical.

I for one do not have that fine a touch using a ball valve to balance. With the T&A valves, I become Goldilocks, and this one is Just Right...