Friday, September 21, 2007
What Type of Valve Is This?
Here is a question I received from Jeremy in Tampa:
I have a digital automated system with electronic irrigation control valves. Zone 3 won't come on unless I manually turn the valve. I've checked the wiring at both ends and it all seems fine. It used to work fine and only recently quit. It looks similar to all three of the photos attached except it has the manual handle on top of the solenoid. I think it might be the Champion valve with the handle added. The bleed screw and top look similar.
I've opened the bleed screw a few times and the system comes on each time just fine, but it won't come on electronically. I'm guessing it's a bad solenoid. Am I correct? is there any further testing I need to do? I'll try to get a photo of it tonight when I get home so you can see exactly what it looks like and maybe you can identify what brand it is so that I can buy the proper solenoid.
By “I’ve checked the wiring at both ends” do you mean that you took volt/ohm meter readings? Here are the steps that you need to take to determine the problem.
Check the voltage at the controller: Turn on zone 3 and place one probe from the volt meter on the common terminal, and the other on the station 3 terminal. You should get a reading between 26 to 28 volts. If so, the controller is working for that station.
Change the setting on the meter to ohms. TURN OFF station 3 and take a reading as described above. Most functioning solenoids will read between 20-60 ohms. Over 60 ohms and you have either a bad solenoid or a wire problem. Under 20 ohms you have a solenoid that is shorting.
Disconnect the wires at the valve, turn on station 3 and check the voltage. You should get 24+ volts. If not it’s a wire or wire splice problem. After checking the field wires, connect the solenoid to the field wires and check the voltage again. If you have voltage with the solenoid disconnected, but NO/LOW voltage with the solenoid connected, you have a “partial connection”.
This means that somewhere in either the zone 3 wire or the common wire there is too much resistance to “carry the load”. In this case the first thing you should do is re-splice the common wire at the electrically upstream valve from valve 3. Often this solves the problem.
If all your voltage is good, check the ohms (resistance) of the solenoid. If it is above 60 ohms, it is the solenoid.
Or you could skip the above steps and do this instead: Turn off the water to the sprinkler system. Unscrew the solenoid and have someone at the controller turn station 3 on and off. If you hear the solenoid “click”, and the plunger retracts, the solenoid is good. If it doesn’t click, connect a new solenoid, if it clicks, screw it into the valve.
Often even a working solenoid will not open a valve that has a faulty diaphragm. The “bleed screw” will release more water off of the upper chamber than the solenoid can, there by opening the valve.
As to the photo’s, valve2 has an Irritrol solenoid, often called a Universal Solenoid because it is the most common and generic design.
Valve 1 has a WeatherMatic solenoid. This would need to be purchased at an Irrigation Supply house.
As to photo 3, why would someone use this thing? Just install a real valve!
I hope this answers your questions. To get the answers to all your sprinkler repair questions, just go here: http://www.howtorepairyourlawnsprinklersystem.com
Craig Borglum CID/CIC/CLIA