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Saturday, May 1st 2021, 9:22pm

Master Valve Won't Open With Controller or Manually

A 10 station Hunter PRO-C controller shows every station to be counting down minutes and the sprinkler symbol is indicating the stations are working but no sprinkler head will rise and deliver water.

The master valve is a Richdel 2400S. I tried opening it with the bleed screw and by rotating the solenoid ccw but neither worked. I installed a new diaphragm but no difference.

Voltage at the controller MV terminals is good at 25 vac but only 3-4 vac at the solenoid wire. Also, the MV wire from the controller shows "open".

I thought the bleed screw or rotating the solenoid CCW would open the valve regardless of the solenoid or solenoid wiring condition? Is this two different problems?



Posts: 2,552

Location: USA


Sunday, May 2nd 2021, 6:09pm

Is there water coming out of the bleed screw when you open it? Maybe the water's shut off?
Open the bleed screw then try to run a valve at the controller. Does it work?
Take the valve back apart, check all the ports for blockage.
I found this pic, I've never seen that port before. See if it isn't clogged.
That valve you have must be 40 years old. Maybe it's time to swap it out.


Monday, May 3rd 2021, 11:31am

Master Valve Won't Open With Controller or Manually

Yes, water comes out of the bleed screw when opening it. Water is not shut off.

Have tried to open all zone valves and master valve with controller but none open.

The Richdel 2400S master valve is 25 yrs old but the diaphragm was replaced 9 yrs ago and again last week.

Thanks for your reply, Mrfixit.



Posts: 2,552

Location: USA


Monday, May 3rd 2021, 3:54pm

Have you tried opening the master valve manually then opening one of the other valves manually at the same time?
Maybe the valves aren't getting power from the controller.


Monday, May 3rd 2021, 5:35pm

Master Valve Won't Open With Controller or Manually

I have tried opening the master valve manually and each zone valve from the controller (but not manually). The output at the controller is good-24vac for all 10 zone valves. The voltage at the master valve is only 3 vac which must indicate something but that should not affect the manual operation.

I have a back flow preventer. Could it somehow be involved? There is water at the master valve when I open the bleed screw.


Supreme Member

Posts: 5,369

Location: Metro NYC


Wednesday, May 5th 2021, 8:22am

A resistance test of the valve wiring would be in order. Reading voltages alone can be misleading.

Also, double-check the water supply shutoffs - all of them. Sometimes the sprinkler system itself is in proper working order, but a gate valve further upstream can be partially closed.

This post has been edited 1 times, last edit by "Wet_Boots" (May 5th 2021, 8:27am)


Wednesday, May 5th 2021, 2:34pm

Thanks for your reply, Wet Books.

There are no closed or partially open valves supplying the sprinkler system.

The MV solenoid resistance reading is good. However, when I disconnect the common and MV wire at the controller and check the resistance, including the solenoid valve, there is no reading on my ohm meter. Also, checked one of the zones the same way with the same result - no reading.

Could this point to the common wire either shorted or open? There is no error code on the controller. Hunter customer service says if common shorted or open, there should be an error code P ERR. They said since there is no error code this points to a loose connection. Connection at controller is not loose. Where else to check?


Friday, May 7th 2021, 3:52pm

Sprinkler fixed! There was a bad splice of common wire where a rain sensor was connected. Sensor not used for many years and was lying on the ground under leaves.

After sensor removed, the master valve and all stations worked. I had forgotten about the sensor.

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