Irrigation system strangeness

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  #1  
Old 05-11-18, 01:34 PM
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Irrigation system strangeness

Does anyone know where I can find an internal schematic for a Richdel 306 PRI mechanical controller for an irrigation system?

Last fall zone 2 could not be energized to blow it out but now it is working fine.

This spring zone 4 activated as soon as the master valve opened for any zone. I expected to find it left manually opened (from when troubleshooting zone 2) but it was not.

I installed the zone 4 solenoid on another zone with the same result there so I expected that the solenoid was at fault.

My controller is indoors and I have installed a DIY service switch outside to facilitate testing and maintenance. The wiring of the switch is in parallel with the zone wiring so the operation of either the controller or the manual switch will turn zones (and master valve) on and off.

Just to make sure that the zone 4 valve was not being energized from the second source, I checked with a meter at the controller terminals and got some confusing results. The common terminal on the controller is not being used. The zone terminals show zero volts when operating and 25 volts when off. Thinking that an additional wire on one of the 24VAC terminals was the common I moved it to the C terminal but the breaker in the controller popped when I plugged in the transformer. Fortunately it reset and nothing was blown but even though the power light was on nothing operated. I opened the controller to see if there was a second fuse but there is none.

Finally I unplugged the transformer, reconnected the "common" wire to the AC terminal, made sure the power button in the service switch outside was off, put the questionable solenoid back onto zone 4 and plugged the transformer in. Everything reset to normal and when I ran through a zone-by-zone test both from inside and outside everything worked as it should.

I am hoping that if I can get the internal schematic I may be able to identify some component that is beginning to fail and avoid an unexpected shutdown. I would also like to figure out how the common "return" from the valve solenoids is wired.

Here is a schematic of the 6-position double-pole service switch:
 
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  #2  
Old 05-11-18, 03:15 PM
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You're showing L1 and L2..... are those 120vac connections or 24vac connections.

All the zone valves share a common wire. If that wire opens out in the field..... all kinds of strange problems will happen. You may also get two valves operating at the same time.

I can't find any technical info on that controller and the company that seems to be the parent is off line. It looks like a mechanical style controller which should be pretty straightforward. You need to be very careful that the controller and your "test switch" are not on at the same time since you are using two different supplies.
 

Last edited by PJmax; 05-11-18 at 03:30 PM.
  #3  
Old 05-11-18, 03:29 PM
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L1 and L2 are 24VAC from the transformer output connection. L1 is the additional wire on the terminal at the controller. L2 shown for the service switch is connected to the common return wire from the valves in a terminal box that I installed outside to splice the service switch into the cable going out to the valves.

That arrangement has been working fine for about 20 years so I don't think the problems I encountered are due to the configuration.

An open wire in the field is possible but there has not been any digging or other activity that might cause that. Possibly just deterioration. Each valve connection has something that looks like a small canister where the wires join. About 1/2 inch diameter and about 2 inches long. What could those be?
 
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Old 05-11-18, 03:31 PM
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Ok.... I was clarifying my original reply while you were posting.
 
  #5  
Old 05-11-18, 03:44 PM
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Same power supply as noted in post #3. When the service switch is on the "power on" light on the controller lights up just as it does when controller is set to "manual"
 
  #6  
Old 05-11-18, 04:52 PM
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Make sure what you are showing as L2 in your drawing is connected to the same place the common is on the main controller.
 
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