I have had my Sprite installed for a couple of weeks and all seemed well, but looking at my garden I realized it was not watering. When I turn it on manually I can hear a short buzz and water entering the valve, but there is no flow. I can open the valve manually and water then flows. I have reverted the valve to the old timer and it then opens the valve, so I don't think the problem lies there. 

I have the black wire on the valve connected to the common terminal, which was how it was set up on the old timer. I cannot figure out what the the problem is. 

I am an international user with a non-Netro PSU, but it seems to as specified: 24VAC 850mA Adapter AC-AC 100V-240V to 24VAC Power Supply Adapter UK PLUG

Can anyone help me overcome this problem with what otherwise seems to be an excellent system?