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I bought this brass ball valve from Home Depot and installed it in the orientation of what I would consider "backwards". I'm not sure if it actually matters and before I close up the wall I would like to make sure orientation isn't an issue with these.

My use of the term "backwards" in this case is when the handle points against the flow of water in the open state.

Model: NSF61-8?

enter image description here

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Globe valves have a direction, when off, the stem is supposed to be on the outflow side of the valve so its packing isn't under pressure when the valve is closed. – Fiasco Labs Apr 20 '14 at 23:10
up vote 6 down vote accepted

If a valve has directionality, it will almost universally be cast as an arrow in of the body, as seen in this globe (aka stop) valve:

enter image description here

I've never seen a ball valve that is directional. If you look inside, you'll see the guts of it are symmetrical.

enter image description here

I would say the general rules of thumb for this are:

  • If you can even change the handle direction, be sure that off is perpendicular to the pipe.
  • If clearance or safety is an issue, then install it in the way that works or is safest.
    • For example, if it's sticking out when it's off and likely for someone to accidentally bump into or get caught on it, then install it the other way so that doesn't happen.
  • If clearance and safety are non-issues, and there are other valves present, then follow the convention of existing valves.
    • If you have pipes that flow in opposite directions it's very handy to ensure the valves indicate this.
  • If there's no existing valves, and no clearance issue, then the most common convention is to have the handle point in the direction of flow.
    • There are probably regional and/or industry-specific variations to this, but as far as North American potable water goes, this is it.
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I installed a brass ball valve about 13 years ago with the handle pointing against the flow when in the on position. It has worked perfectly. My valve is female by female so the direction did not matter when assembly the piping. In short: a ball is round so direction does no matter. If a valve must be installed in a certain direction is should have an arrow cast into the body showing the direction of flow.

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Without hunting through all the spec sheets to find your particular valve or at least one that looks just like it (not having a number) I note that none of the spec sheets I did examine at Apollo valve for brass/bronze ball valves indicated any directionality (and in fact, you can usually put the handle on the opposite way if it's more convenient. Perhaps not on that model, looking closely.)

Apollo Valve Spec Sheets

This also matches my experience using ball valves, generically.

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I have disassembled a few ball valves for cleaning and they have all been symmetrical. – Henry Jackson Apr 20 '14 at 18:55
NSF61-8 is the model number – Joe Philllips Apr 20 '14 at 19:46
or maybe it's 600CWP – Joe Philllips Apr 20 '14 at 19:50
600CWP is the "Cold working pressure" in PSI. – Pigrew Apr 20 '14 at 20:01
And NSF61-8 is NSF/ANSI 61 Section 8 “Drinking Water System Components - Mechanical Devices (Low Lead and chemical / organics leaching test) Don't worry about it too much. – Ecnerwal Apr 20 '14 at 21:22

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