SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Do not put a filter in front of control (zone) valves unless you are using dirty water through the sprinkler system. Automatic control (zone) valves are designed to last a long time without any prefiltering of the supply water, unless you are supplying the system with dirty water from a lake, pond or other source.

<b>If you are using dirty water:</b>

1. If you're working on sites where the primary water source is lakes, ponds, streams or effluent, it's very likely that you deal with "dirty" water. Since the dirt and debris from this kind of water can choke an irrigation system, picking the right equipment is vital—and nowhere is this more vital than in the selection of the correct remote-control valves.

When you select a remote-control valve for a dirty water application, make sure it has filtration features incorporated into the valve by the manufacturer. This is a very important , because not all valves have filters and the area on top of the valve diaphragm and the solenoid area is extremely susceptible to damage from fine particles of dirt and debris. The best method for filtration manufacturers employ to prevent dirt from contaminating the valve and interrupting operation is the "self-flushing" screen.

A filter or screen that is self-flushing prevents water containing dirt and debris from entering the top of the diaphragm and the solenoid. Located on the bottom of a valve's diaphragm or inserted into the side of the valve body with a tube connected to the base of the solenoid, the screen or filter positioned in the stream of water running through the body of the valve. The water flow continuously flushes the filter screen, dislodging particles and debris before they can accumulate and clog the filter.

One manufacturer's valve, which is particularly effective in dirty water, is the Rain Bird PEB series of scrubber valves. This series of unique valves have a scrubbing action, which occurs every time the valve is opened and closed. The fingers of the plastic scrubber removes dirt and debris by scraping the stainless steel filter screen clean as it moves up and down with the diaphragm. The action constantly breaks down debris to prevent build-up and clogging.
To see the Rain Bird PEB valve, click on the following link:
http://www.sprinklerwarehouse.com/shop3/ValvesRain_Bird.html

2. Furthermore, if you are using dirty water, you should put a filter in the mainline after the pump but before the master valve or backflow prevention device. If you do not have a backflow prevention device or a master valve, you should put the filter before the mainline splits off to feed a zone valve (section valve). Furthermore, install on suction or discharge side of system. We suggest installing between the pump discharge and the reservoir tank if you are using a tank. Install on the discharge side to allow use of a purge valve for easy one step cleaning. Manifold two or more filters for applications with flow rates higher than 100 GPM.

The filter will help keep the valve screens, which are usually located in a valve on the diaphram, from clogging. It will also help keep debris from the lake from preventing the diaphram from sealing or completely closing and help keep nozzles and nozzle filters from clogging.

The type of filter to use is the Vu-Flow T Style Screen Filter. To see the filter and read more about how to corectly size the filter and screen mesh selection click on the following link and then click on the picture of the Vu-Flow filters:
http://www.sprinklerwarehouse.com/shop3/MiscMisc.html
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