Learned something about valves today

[mark]

Sure most know this but pointing out for those that might not.

Was replacing my pump by undoing both true union PVC valves that I have before and after the pump. Pump was out but the valve from the tank had a slight drip so cycled it back and forth a few times to see if it would stop when the seat and ball just came right out.

Lucky only a little water in the line as had allowed most to drain back and was playing with it over the sump. If I hadn't drained back to the sump before turning the valve closed could have been 30 gallons on the floor.

Ends ups the valve I have are made to come apart. Something I never realized but that arrow isn't for flow direction but points to the fixed seat side of the valve.

Good thing I fluke off the valve on the sump, potential for 75 gallons there if it would have let go with the pump out.

Picture shows what I'm trying to describe, tape on the valve is the direction of arrow.

[untamed]

Holy (*^()!

I have the same valves...a lot of them...holding back a lot of water (like 500 gallons) and did NOT know that the balls can come out of them.

So you want to install these such that the pressure is pushing with the direction of the arrow while you are disconnecting things.

For example....One installed on the output of the return pump needs to be installed with the arrow pointing toward the pump. (which would be AGAINST the direction of flow when it is running)

You may have just saved me from an epic disaster some day! Thanks!

[andresont]

One more vote against closed loop systems.

[Dale]

Hi Mark,
Did the valve strip off of the threads or was it just barely screwed on so that a bit of movement knocked it loose? Just curious.

Not sure how this is a vote against closed loops though andresont? Care to explain.

[untamed]

[quote=Dale;224639]Hi Mark,
Did the valve strip off of the threads or was it just barely screwed on so that a bit of movement knocked it loose? Just curious.
QUOTE]

No..no..the valve hasn't failed. They are designed this way. I just didn't know it. In this way, the valve can be fully disassembled and serviced. You can remove the ball portion, relubricated the o-rings...it's very nice.

It does, however, mean that the ball valve will only support pressure in one direction WHILE THE UNION IS DISCONNECTED. That means that there is a definite "right" and "wrong" direction to install them.

I think in this case, he had the union disconnected on purpose because he was servicing the pump. That's why it is there. It all works safely, as long as you have it installed the right way 'round.

I just spent an hour or so reversing 12 of my 14 valves because I thought the arrow was a flow direction as well!

[Psyire]

yikes... good to know, thanks.

[mark]

Originally Posted by untamed

Holy (*^()!

For example....One installed on the output of the return pump needs to be installed with the arrow pointing toward the pump. (which would be AGAINST the direction of flow when it is running)

That's right. On the valves I have, arrow points against the permanent seat.

Also note this valve was not on my closed loop (though I used same valves) but on the return pump from the sump.

[ZachAttack]

Well, this is definitely good information to have as I am planning on doing some plumbing for myself in the very near future, thanks guys

So just to recap, if I have the valve between my pump and the return line going up to my tank, I want the arrow pointing towards my pump, or towards the return line leading back up to my dt??

[michika]

This deserves to be a sticky! Hugely important detail that I'm sure many people should know about.

[mark]

Originally Posted by ZachAttack

So just to recap, if I have the valve between my pump and the return line going up to my tank, I want the arrow pointing towards my pump,

Yes.

From the picture, the pump would be connected on the left side. That way when you remove the pump (by undoing the coupling not show) the ball stays in-place.