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bdnannac

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1

Tuesday, July 17th 2012, 12:58pm

Vibrating PVB

I installed a new 3/4" PVB that goes to a 1" before reaching the valves. Could that cause the PVB to vibrate and spit water for up to a minute when the system is starting up? I checked the inside parts and they all look OK. It's a brand new PVB so I'm stumped. Any ideas?

Wet_Boots

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2

Tuesday, July 17th 2012, 3:20pm

If the PVB is a Wilkins 720, it can release water during a large drop in pressure. Not a problem, though.

bdnannac

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3

Tuesday, July 17th 2012, 3:33pm

It's a Conbraco 4A-504-02F 3/4 in. First couple of times it ran fine with no noises. Today I tried to see if it was a valve problem. Changed 3 of the diaphragms on the older valves and tried to isolate them. So when I start the system without 2 of the valves on there is no noise at all. Could this be a valve problem instead? The 2 valves in question are quite old.

Wet_Boots

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Location: Metro NYC

4

Tuesday, July 17th 2012, 9:21pm

Any time a PVB spills water, it is telling you the system design is suspect, because the water pressure should not be dropping so low when a valve opens. If your valves had flow controls, you could throttle them down.

bdnannac

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5

Wednesday, July 18th 2012, 12:58am

OK thanks Wet_Boots. I guess I'll replace the 3 old ones and see if that does the trick.

Wet_Boots

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Location: Metro NYC

6

Wednesday, July 18th 2012, 8:38am

First, check the plumbing upstream of the PVB. You're looking for any shutoff valve that is partially closed.

bdnannac

Unregistered

7

Wednesday, July 18th 2012, 4:37pm

Good idea! I'll do that first. Thanks again.

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