Solenoid function on a irrigation valve?

Pmaru77 · Apr 13, 2009

Well, while I'm trying to repair/fix my valve leaking problem, I thought I'd ask how a solenoid valve drop the pressure on one side of the diaphram valve so that the diaphram opens to let flow to the sprinklers. I am assuming that there is more pressure on the top of the diaphram when shut, thus shut. So, does the soleniod (retracting type) drop that pressure somehow?

Jadnashua · Apr 13, 2009

A solenoid valve is an electrical device...apply power, and it moves a piston. that piston might be attached to a valve or any one of many devices. Sometimes that piston has a spring to return it to 'neutral', and some require reversing the polarity of the field, or a second actuator.

Sponsor · 2022-01-29T12:20:58-0800

Jimbo · Apr 13, 2009

Sprinkler valve are pilot operated. When the solenoid is off, an internal port allows mains pressure to be applied to the top of the diaphragm. A small spring adds to this pressure, whereas the underside of the diaphragm only sees mains pressure, so the diaphragm remains closed. When the solenoid is activated, it opens a port which bleeds mains pressure from the top of the diaphragm into the outlet pipe. This bleeds faster than the inlet bleed, and thus mains pressure on the underside lifts the diaphragm.

Thatguy · Apr 13, 2009

http://wpcontent.answers.com/wikipe...a/Solenoid_Valve.png/360px-Solenoid_Valve.png

Pmaru77 · Apr 14, 2009

jimbo said:
Sprinkler valve are pilot operated. When the solenoid is off, an internal port allows mains pressure to be applied to the top of the diaphragm. A small spring adds to this pressure, whereas the underside of the diaphragm only sees mains pressure, so the diaphragm remains closed. When the solenoid is activated, it opens a port which bleeds mains pressure from the top of the diaphragm into the outlet pipe. This bleeds faster than the inlet bleed, and thus mains pressure on the underside lifts the diaphragm.

Very good......thanks. So the diaphram does have water on both sides as I thought. Also to add, the line pressure has more surface area to push on the top of the diaphram, thus more pressure downward. I think the spring keeps everyone(diaphram) in place and order while adding a little pressure. I still have not figured out why this 75 dollar valve is passing water. I cut it out for now and end capped the line temperarily.

Pmaru77 · Apr 14, 2009

Thatguy said:
http://wpcontent.answers.com/wikipe...a/Solenoid_Valve.png/360px-Solenoid_Valve.png

That is exactly my setup....thanks. Oh...buy the way....I cut the lines to the valve and took it out and apart, and the seat is cracked....hardly noticable until you put a little pressure on it. So much for a $75 Irritrol valve.

Jimbo · Apr 14, 2009

pmaru77 said:
Very good......thanks. So the diaphram does have water on both sides as I thought. Also to add, the line pressure has more surface area to push on the top of the diaphram, thus more pressure downward. I think the spring keeps everyone(diaphram) in place and order while adding a little pressure. I still have not figured out why this 75 dollar valve is passing water. I cut it out for now and end capped the line temperarily.

Good point. Hydraulics is all about pounds PER SQUARE INCH

Solenoid function on a irrigation valve?

Pmaru77

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