Sillcock hammering

[Esteffe2]

Hi there,

I have a 6" Everbilt frost free sillcock with vacuum breaker and recently attached an irrigation system and timer valve. When the timer valve closes, the sillcock begins a repetitive banging noise about 3 times a second. During each bang, a small amount of water squirts out of a small hole in the sillcock shaft. I am guessing what is happening is when the valve closes abruptly, the water pressure on either side of the sillcock seal washer equalizes and the spring pushes the valve closed. This allows water in behind the washer into the shaft and vents the pressure (squirt). This creates an imbalance and the sillcock washer is pushed back by the house pressure again, filling the whole valve, the spring pushes back and it happens again .... Bang bang bang.

Possible solutions?

I thought of cutting the spring to reduce the force, and filling the hollow shaft with epoxy to stop the squirt... Thoughts?

 

[frodo]

can you please show use the piping configuration of this set up ?

picture is best but a drawing will do

 

[plumb_bob_square_pants]

Don't cut the spring. You need a hammer arresters at the new irrigation system. Preferably between the timer valve and the rest of the system. Really need picture because not knowing how things are set up can affect the placement and Also its sizing.

 

[frodo]

a globe valve will make that racket if plumbed backwards

i suspect the washer on your bib is chattering, but need to see the piping configuration to be sure

 

[plumb_bob_square_pants]

I've never had to put in a globe valve. I have often wondered what the benifits of them are verses other valves. What are the best applications for them? And do they work like a type of metering valve if they can chatter when installed backwards?

 

[frodo]

you can see how the water can hit the side of the bib washer and make it chatter

they are great for a metering valve

we used them years ago for the valve at the w/h. i do not know why

cheaper maybe ? LOL know ing him most likely

 

[KULTULZ]

Diagram showing correct direction of flow-

 

[plumb_bob_square_pants]

So for a hose bibb... it looks like they are designed similar

 

[frodo]

remove vacuum breaker from end of frost proof hose bib

re attach timer


need pictures!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Esteffe2]

Here is a picture, I hope this helps

 

[frodo]

i see a vacuum breaker

your atmospheric vacuum breaker is doing its job.

 

[plumb_bob_square_pants]

plumbing master frodo. Please can you explain your deductions. Your kung-fu is better by far.

 

[KULTULZ]

plumbing master frodo. Please can you explain your deductions. Your kung-fu is better by far.

That's Plumbing Master frodo-son...

 

[plumb_bob_square_pants]

I always wondered what frodo looked like. My imagination was right on the money.

 

[frodo]

what i am thinking, been thinking all day, but not sure

when the timer shuts off, it is useing a fast acting valve

the water thru the h/b is still on, the action causes the vacuum breaker to open [as it should] but with the water still on,

and the VB open, that is where the water the op is seeing is coming from...backwards thru the VB

it has opened and vented water not sucked in air

next is the hammering,,not sure, it is either the VB diaphragm but i suspect it is the check valve on the stem slamming shut from water going back inti the house ..check valve is being pushed in the opposite direction as to which it was intended


this is just guestimention ....


this unworthy Forrest gnome is of no match to be snatching pebbles from the master
he holds his hand out, i catch air every time....now if he were to have a gold ring........

 

[plumb_bob_square_pants]

I had in my head a completely different system. I was thinking commercial not residential. Was not thinking it was screwed into the hose bibb. I not only caught air but a pebble to the forehead.