Question
This was installed 2007 and worked fine until just recently and we don't know if the freeze had anything to do with it.  It will now water all zones and generally only 3 but they are intermittent.  We notice the manual setting will cause the screen to flash and change so it may be the circuit board is bad.  I have reset the unit and also turned off the sensor as the book indicated it will cause problems.  We have no lights on indicating any zone issues with the solenoid, etc , however,   I just ran the Raster(?) test and it says Master Valve, Valve 2 and 4 have an open circuitry to ck wiring and the solenoid.  Now the problem is the installer never marked anything on the charts so we have no clue where these valves are!  Any idea's please?

Answer
Hi Brad

This means that the circuit between the controller and the valve is open, no current flowing. This can be caused by:
1.- A bad selenoid. To check measure the omhs at the selenoid disconnected from the controller if the results are greater than 60 the problem is the selenoid, so replace it. If the results are any given value between 20 to 60 omhs the selenoid is fine, so:
2.- The wires get cut somewhere. Check for recent digging activities by the path to the valve, if something has been done dig to find any broken wires.

If you don't know were the valves are you need to use a wiretracker (like Armada 700, costs like $ 1000) to locate the valves. Probably will be better to hire an irrigation company to do this.

The master valve (if one exists) is generally located close to the outlet line, the one from the pump to the valves. Usually when the system doesn't have one you get the open circuit message when  run the raster test.

BTW RASTER = Rapid Station Test Routine

Regards
Guillermo