Question
I have a raildial spinkler system with two stations. recently, while sprinkling, I heard noice from the all solenoids. It's like a hammer going up and down inside the solenoid. There is water coming out from al sprinkler heads, but it's weaker than usual.

Batter was weak in the raindial controler and it's been replaced. didn't fix any problem though.

Can you help me?

Thank you,
Larry

Answer
Larry,

If both of the solenoids are making this noise, it is likely that you have a problem with the controller.  The sound you are hearing is the solenoids turning on and off.  Barring any wiring issues, its likely that your controller needs to be replaced.  It would be very improbably that both solenoids went bad at the same time.  You might want to also check that the water line that supplies the system is fully opened as well.