#915 Understanding and Troubleshooting Valves
Mastering your irrigation system
The major parts of your irrigation system are: Controller (or clock), Valve, Water lines, Emitters (or sprinklers) and Accessories (like Back Flow- Filter – Pressure Regulator). Valves have moving parts, unlike these other sections, and therefore are the most likely to wear out of fail. Understanding how valves work, and how to troubleshoot them is key to mastering your irrigation system.
◊ INTRODUCTION to VALVES
◊ SYMPTOM – VALVE STAYS ON
◊ SYMPTOM – CURRENTLY INSTALLED VALVE WON’T ACTIVATE
◊ SYMPTOM – NEW VALVE STAYS ON
◊ SYMPTOM – NEW VALVE DOES NOT COME ON
INTRODUCTION to VALVES: Irrigation devices directly controlling water flow to sprinkler heads are known as valves. The principle behind the inner workings is very simple. A spring loaded diaphragm drives the gate attached to it against the seat which prevents water flow. There is normally water pressure on both the top and bottom of the diaphragm, and this allows the spring to keep the valve shut.
Mechanically an electronic solenoid actuates a “bleed” valve that relieves the pressure for the top of the rubber diaphragm, and then the pressure on the bottom of the diaphragm drives against the spring and opens the valve. There is also a mechanical bleed mechanism on most valves allowing a temporary testing of the valves operation. When either the bleeder screw/valve or the solenoid opens, pressure is released and water passes through the valve. (top)
There are only two moving parts of a valve that can go bad, the solenoid and the diaphragm. The solenoid is electro-magnetic. A spring is wound around a metal core (the plunger) and is sucked in when power is applied. The plunger is positioned over the bleed port which allows / does not allow water to be removed from the top of the diaphragm. Diaphragms are the number one cause of most problems. Unfortunately many people try to replace the solenoid first because it is the easiest thing to replace. A small dent caused by a rock, or a tear in the diaphragm can cause it to not seal properly. (top)
Next we will explore some common valve problems and their solutions:
Manual flow control
Diaphragm SYMPTOM – VALVE STAYS ON: *
Bleed valve Water exit
- Solenoid is rusted.
- Hardie 205 Valves built prior to 1997 had a rusting pin. Bring in the top of the valve, and a Star Nursery irrigation associate will replace it with a new one.
• RainbirdDV-100hasacreamcoloreddiaphragmwithaseparateo-ring.The replacement part is a black colored one-piece unit. Try replacing the diaphragm on this valve before the solenoid.
• Actuatorvalves(L1034&L2034).Replacewithawholenewassembly,it’snotworth trying to find another solution..
SYMPTOM – CURRENTLY INSTALLED VALVE WON’T ACTIVATE: *
- Irrigation main has been shut off.
- Problemwiththetimer. (top)SYMPTOM – NEW VALVE STAYS ON: *
• Airbubbletrappedontopofdiaphragm.Turnthebackscrews5timestopurgeair. • Valveinstalledbackwardsorupsidedown.
SYMPTOM – NEW VALVE DOES NOT COME ON: *
• Nopower.Checkallconnections.Wiresleadingfromthetimermaynotbeconnected at some point. Check connection points outside house where wire from timer enters the ground, and at solenoid on valve in valve box.
These are most of the reasons why a valve is not working properly. If you have the opportunity, take a valve apart and match the parts to the attached diagram. This diagram is for Hardie / Irritrol® 205T /TF, 204LG, and 204APR/PR valves.
*Some new valves like Richdel, Hardie or Irritrol, and replacement solenoids for these valves, come with a white plastic ring around the plunger. If your solenoid has this ring, and your valve either won’t shut off, won’t turn on, or doesn’t have full power, use a screwdriver or pliers to remove the ring, then reinstall the solenoid. This may solve your problem.
©2009 Star Nursery, Inc.