3 way steam valves which outlet is steam in, steam out, bypass?

john seickel

Which port is steam in, steam out,and bypass?

Al Letellier_9

3-way valve

Depends on the manufacturer. If marked A-B-AB the ports would be A inlet B oulet AB bypass, but it could be different. Find out who manufactured the valve and contact their rep. Don't take my word for it.....

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Al Letellier_9

3-way valve

Depends on the manufacturer. If marked A-B-AB the ports would be A inlet B oulet AB bypass, but it could be different. Like A inlet, B bypass, etc. Find out who manufactured the valve and contact their rep. Don't take my word for it.....

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john seickel

the ports are NO, NC, and C The brand is florite VF 599 Series

bob young

fielders choice

normally open = nm , normally closed = nc , closed = c.. thats your options , take your pick.

john seickel

The question is where do you pipe steam in, and steam out. What is the purpose of the third port?

bob young

in what application is the valve being used ??? what do you want it to accomplish ?

JJ_4

Valve Ports

It does depend on the manufacturer where physically the ports are configured (bottom, left, right), but the notations mean the same thing. I don't think "C" ever means closed. As one of the posters said check with the manufacturer and get a cut-sheet.

If you happen to have a Barber-Coleman valve they are typically configured as such:

"A" is NC or Normally Closed

"B" is NO or Normally Open

"AB" is also often called "C" or Common

If this is a mixing valve, then "A" and "B" are the inputs and depending on the position of the valve what goes out "AB" is either "A" or "B" or a mix of both "AB".

A hot water configuration would be piped to fail for flow through a heating coil (as in an air handler). The valve spring returns on actuator failure, or trip of a freezestat, to protect the coil and also so you will continue to heat the building until repairs are made.

If the "B" port closes, then a supply bypass pipe will allow flow through the "A" port, to the "AB" port as return.

I'm going to try to attach a drawing for hot water. Chilled water is the same idea, but usually set up to fail in bypass. It's been too long since I've worked on a steam system to remember how to pipe. I think they should fail open for coils except if a heat exchanger is used, then fail closed to prevent over heating the water side. Dr. Seigenthaler or Dan Holohan would know.

If you pipe these the wrong way, say using the "C" as an input, then water will flow, not necessarily in the way you want, and it will be noisy and the interior of the valve body will errode.

There are also 3-way diverting valves. These are "one-inta and two-outa". They dirvert the input two different directions. The mixing valve is "two-inta and one-outa". Make sure you get the right application.

The drawing is in Microsoft Publisher because it is the only drawing program I have access to...

Hope this helps...but once again check with manufacturer.