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whitty

New Member

1

Friday, April 20th 2012, 8:09am

Controller & water flow shut-off options

I have a Watts PVB backflow preventer. My installed system is a small 4 zone system in a small lot. Zone 1: 3 sprinklers in the front, Zone 2: 4 sprinklers in the back and Zone 3: 2 drips lines. I am also installing a small fertilizer injector.

My problem is with leakage appearing to be coming from the bell cover, which possibly can be attributed to a pressure issue. The problem doesn't occur when the low pressure driplines are running, but will occur when the sprinklers first start. Troubleshooting resources suggested partially closing the valve after the PVB, which appears to resolve the issue. I still am not 100% confident this water leaking issue is resolved so I don't run the system automatically or when no one is home.

My old controller only allows for run times of 99 minutes, so I am looking for a new controller. There appear to be some controllers that have some flow monitors that will shut the valves if there is leakage. My problem, however, is from the water feed line to the PVB rather than from the PVB to the valves and then sprinklers. The water line feed is copper from the main all the way to the PVB which then attaches to polytube and then the sprinklers. Can a master control valve be installed on the copper line inside a house with a flow monitor on the other side prior to the PVB? I would like some failsafe method to stop the water flow to the PVB if this leakage issue occurs.

What options are available for stopping the water leakage if it does occur (ex: flow monitors) and which controllers are recommended for such a set up?

I have researched the Toro TMC-424E-ID and the Weathermatic SL1600. The Toro appears to have this flow functionality, but I am not sure if the Weathermatic does. The flow monitors themselves seem to be pretty expensive as I have a relatively limited budget. Preventing water from pouring into my basement from the PVB bell cover, however, is potentially expensive as well which may justify any investment.

Thoughts?

2

Friday, April 20th 2012, 9:38am

Generally, a master valve and a flow sensor can be set before a PVB. No reason not to, barring physical restrictions.
You don't need a particular controller. You can use something like the Hunter Flow Sensor with pretty much any 24vac controller.
It sounds a bit like a pressure issue or it could be a failing PVC.
My first step would be to rebuild the PVC. It's very simple and kits are cheap. Our Watts page is HERE.

Central Irrigation

Supreme Member

Posts: 305

Location: Central Minnesota

3

Friday, April 20th 2012, 6:29pm

You could also put check valves in your sprinkler heads or try reducing nozzle size.

Wet_Boots

Supreme Member

Posts: 3,876

Location: Metro NYC

4

Friday, April 20th 2012, 10:00pm

Avoid having electric valves upstream of a PVB. Some makes and models do not endure repeated pressurization.

Get a pressure gauge, and read system pressures when a zone opens.

whitty

New Member

5

Sunday, April 22nd 2012, 2:01pm

controller & water shut-off

Thanks for the feedback. I think I am going to explore the master valve & flow control set-up. I have actually take water pressure reading for each zone, but cannot recall what the pressure is when each zone runs. The 4 sprinkler uses more pressure than the other two so I might remove one of the sprinkler heads in the back (reducing 4 to 3) as well.

Rain bird brass valve $78.09
Hunter-Sprinker-Flow-Clik-Sensor-Tee $172.44
I have not decided which controller to get yet.


Upon further research, it appears my PVB probably won't meet the backflow requirements when using a fertilizer injector. It looks like I need to get a Reduced Pressure Zone Assembly. Not sure how difficult these are to install. I might open a new thread to discuss this. I have seen other posts regarding installation, but could use some additional feedback as well.

I saw this 'plumbing circuit breaker' http://www.flologic.com/flologic-guide/FloLogic-3.0-Feature-Specification.pdf used on This Old House, but I don't want to spend $1500 on such a system at the moment.

Wet_Boots

Supreme Member

Posts: 3,876

Location: Metro NYC

6

Sunday, April 22nd 2012, 2:23pm

For small money, just make the current system functional. Do not put a master valve upstream of the PVB. Downstream of a PVB, a master valve with its flow control throttled down can be a cure for the water coming from the PVB, because it better maintains upstream pressure.

whitty

New Member

7

Sunday, April 22nd 2012, 2:33pm

RPZ fix a pressure problem?

I have actually disassembled the PVB unit
previously, but this did not fix the problem.
I believe it is a pressure problem as the issue only occurs when I start the 4 sprinkler zone. Would a reduced pressure assembly have any impact
on this issue or would a pressure issue remain? Last year I had some success with closing one of the valves on the PVB to at least decrease the potential water leaking from the top, but still it wasn't 100% reliable. Unfortunately, I have not been able to replicate it this year. With the installation of the fertilizer injector, it seems that a RPZ is needed anyway.

Central Irrigation

Supreme Member

Posts: 305

Location: Central Minnesota

8

Sunday, April 22nd 2012, 2:42pm

My concern is that an RPZ will rob even more pressure from your system. RPZ's, on average, have double the pressure loss of a PVB. If your system pressure is already that low, an RPZ could be too much pressure loss.

whitty

New Member

9

Sunday, April 22nd 2012, 2:53pm

water pressure

The main line water pressure is 100, which I believe is roughly reduced by 15 by each sprinkler head (reduced by 60 by the 4 sprinklers in zone 2 and reduced by 45 by the 3 sprinklers in zone 1). I have a 15psi regulator on each of the two drip lines in zone 3, but have not confirmed the pressure. I have noticed a small leak in the polytube roughly 10 feet from the PVB and the first valve tee which obviously would cause a pressure issue. Perhaps when I fix this, the water pressure issue will be resolved but I believe the water pressure issue has existed prior to this leak.

What is the proper operating pressure? The PVB is rated up to 150 I believe. If one doesn't have adequate pressure, what are the alternatives?

Central Irrigation

Supreme Member

Posts: 305

Location: Central Minnesota

10

Sunday, April 22nd 2012, 2:57pm

What size line feeds your pvb? 100psi static pressure would never allow a pvb to break it's seal so long as it's supplied with the proper amt. of water!
You have PLENTY of static pressure. Proper operating pressures vary from 35-75psi.
FYI....you're working your pressure losses backwards. Always start where the water starts and follow it through.
Bottom line is, your system is demanding more water than your house can supply, that's why your pvb breaks it's seal.

This post has been edited 1 times, last edit by "Central Irrigation" (Apr 22nd 2012, 3:03pm)


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