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I have an Irritrol TC-15EX-R - Total Control Series 15 Station that I just installed. (to replace older total control because I was told the control was done - Master Valve error)

When I try to manually turn on any station - nothing... just shows "Master Valve" I spoke with Irritrol troubleshooting dept. I turned off ALL master valves through setting since I do not have a master valve. Still INOP - they could not help any further.

Power to unit - water to system .. not sure what to do now.

Hey Danny, you say you do not have a master valve, do you have a pump hooked to the system? It could be a pump relay that is shorting out the MV terminal.  If you go to the individual valve, can you turn it on manually at the valve, I am trying to determine if you have water to the valve. I find it odd, that the master valve error occurred on the old controller, and now it is showing the same thing on the new controller, but you claim you have no master valve!! This is what I would do, go to the individual valves, and make sure you are getting water to the valves, if you are not, then you probably have a master valve. If you are getting water to the valves, then you have no master valve. If you do not have a Master valve or a pump start relay, then in back of the controller on the terminal strip, make sure you do not have a wire hooked to the MV terminal screw. Now turn a valve on from the controller, lets say #1. Take a volt/ohm meter and put the positive lead on the #1 terminal screw, and the negative lead on the C (common) terminal, and see if you are getting between 22 to 26 volts. If you are, then the controller is working properly, and you need to check the wires at the valves themselves with the volt/ohm meter to see if you are getting power to the valves. If you are not getting power on the wires at the valves, then you either have a break or short in the wires to the valves. If you are getting the proper power on the wires to the valves, then the valve(s) is defective and needs to be repaired or replaced. Normally on the old controller when it says, "master valve error" there would have been something hooked to the MV terminal that is shorting it out. That is why I am puzzled to why if you have nothing hooked to the MV terminal it would give you this error message? Let me know if you have anything hooked to the MV terminal, so I can be of further assistance. Thanks and have a great day.


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Jim Schaefer


Any question regarding sprinking systems,installation,repair, and trouble shooting.


I have been installing and repairing sprinkling systems since I was 15 years old. Have owned my own sprinkler system contracting business for over 26 years. It is basically the only job I've ever done, except for being a paper boy when I was young.

High School diploma and 3 years college credits.

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