I have the same problem...i have tried to turn the valve on manually however I still only have a stream of water come out and the same thumping...what should i do???
When my valve comes on I hear very loud thumping in the lines and the heads bob up and down...sometimes just a steady stream of water will come out but no spraying...they used to work perfectly until one valve died and i replaced it...now this...what could be wrong...thanks
