Severe Continuous Pipe Vibration When Valve(s) Open

[goof99]

Speed-my thots exactly. Still it is a longitudinal crack and it is way too narrow for an insertion plus it was buried. Moles most likely pushed up dirt into the box - they do everywhere else. Might it have been a weak spot? It held for 31 years. Could changing the meter just be a coincidence? Neat mystery.

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This morning there was a vibration in the 1st circuit. Not severe but it did get my attention at 4:25am. By now I'm so goosy a loud exhaust or even a train rumbling past about 3/4 mile away gets to me. Kitchen refer too.
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The new PRV weeps! Both sides. That tics me off. It's a Watt. New improved. Instead of the flat washers it has "O" rings. The nuts are bottomed out tight. I will undo and redo it today see if I can stop that weep. I did not grease the "O" rings and should have; tired probably. I won't say what country it was made in but if you dig a hole straight down thru the earth you'd get there.

Otherwise it's coming out and straight PVC will go in. I'll have to dig back and get clever cause there are 2 - 45º bends to get perfectly lined up with the meter. Easy for a pro I spose but I ain't that.
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DungBuster: Nice Handle - I used to haul bagged fertilizer otherwise known as steer manure. Had plenty of elbow room sitting at cafe counters.

Here is the schematic you asked for. Hope you can see it OK. I had to take a photo of the Paint screen to get it down to size.

If you read post # 26 you will see this proved the problem originated between the house and street. I have racked my feeble excuse for a brain as to how air could get in and/or cause the problem.
As for a schematic of the entire house/sprinkler system might as well throw some spaghetti on a plate.

 

[speedbump]

Speed-my thots exactly. Still it is a longitudinal crack and it is way too narrow for an insertion plus it was buried. Moles most likely pushed up dirt into the box - they do everywhere else. Might it have been a weak spot? It held for 31 years. Could changing the meter just be a coincidence? Neat mystery.

Hard telling what caused it, but I have seen my share of 1" Male Adapters buried and broken, but never one with an injury like yours. Most of the ones I have seen broken were at the threads where they met the metal fitting they were screwed into.

 

[goof99]

OK removed and greased the "o" rings and cinched the nuts up but not super tight and it held but did start to weep again. Tightened a bit more - still weeped. Water comes out along the tailpiece. The O ring is only 1/32 higher than the flange and is exactly same dia as the flange. Seems those dimensions are cutting it a bit too thin for my taste. The old flat washer is much better.



Anyway looking it over real good there are 3 - 45º joints and w/o the PRV I can just replace all that with one 45º joint - a good option for a rooky.

 

[goof99]

NM 10 Characters

 

[Beni]

Vibration in water piping when a valve is closed suddenly, specially when a solenoid valve closes, is caused by water hammer. That is the moving water instantaneously hitting the closed valve. Water hammer is a pressure wave that propagates back and forth in the piping. The pressure wave will be roughly will be 60 times the static pressure in the system. There are nice formulas for calculating that, but in the end its about 60 times static pressure

Over time water hammer will break pipe and pipe fittings.

The solution is to install either a water hammer arrestor like a Zurn Z1700 or install a air chamber upstream of the solenoid valves.

A air chamber is a vertical piece of pipe with a cap on the end, roughly 16” long x one size larger then the line it serves. It's installed upright. The air chamber works but over time (years) it will get water logged.

While all plumbing codes require water hammer arrestors, they are normally missing from residential single family construction.

Beni B., PE, CIPE

 

[zake11]

Shutting off the Service Entrance Valve ( Main water valve for house water only) stops the vibration when the sprinklers are on , Right. What type of service entrance valve (Main water valve) do you have . (ie. gate valve, ball valve).

 

[Geofd]

the last poster is right....if there is a back flow preventor
on your irrigation (with spring loaded check valves) they can chatter
whenever I install a pvb,eps,or dcva (all back low devices. With spring loaded
checks or releif valves) I n stall a spring loaded check valve
in front of the back flow device it will keep the irrigation side pressurized
so the back flow checks don't react to to pressure loss