Check valve / non return valve question

[Subby]

Does anybody know what the hexagonal bolt is for on the side of a check valve?

 

[Howsie]

To let water out.

 

[snowhead]

Depends how big the valve is, on larger ones the bolt is the pivot for the flap valve inside.

 

[newagegasman]

I think i was taught that it was to check if you installed it the right way around...

 

[Subby]

So if I have a 42mm check valve with a drainoff below it, the water flowing upwards through the check valve and up through the cieling, is it possible to drain the water that is above the check valve, ie opening the flap somehow?

 

[vern]

Does anybody know what the hexagonal bolt is for on the side of a check valve?

It's actually to bleed air out of the spring loaded side to allow that side of pipe to fill....simples

 

[martin b]

Its to verify that the check valve is working, thats why they are called verifiable check valves

 

[vern]

Its to verify that the check valve is working, thats why they are called verifiable check valves

In that case everyone installed would need an isolation valves either side to check which way the water was flowing...

 

[Plumb Ugly]

Lol it appears everyone has a different opinion on this one! Iv wondered myself and had theories but I don't know so I'll not add mine!:45:

 

[Subby]

Come on... we all want to know what you think it is for, I thought it may be to open the flap. This debate is quite interesting with all the different replies.

 

[snowhead]

I'm sticking with my answer for larger ones, (Pivot bolt) and I'll post a pic later if I can find one to strip.

 

[chris watkins]

Its to verify that the check valve is working, thats why they are called verifiable check valves

Martin's right (unless the OP is talking about a swing type non return valve) they are called verification ports & allow the operation of the spring check valve to be checked. They can be on both single & double checks, the is the different between singles EA & EB The doubles are EC & ED. It does not effect the fluid category.