Can anyone give me any ideas on my problem please. Problem occured when I lost hot water but still had heating, fault found to be above valve (no flow into hot water tank). Tried to manually operate lever but was solid, actuator head has been taken off and valve body operated and is free (when in hot water position there is flow into hot water tank). Automatically I assumed problem with actuator, I was only able to get a replacement synchron motor not a complete actuator head. This was installed into actuator/valve to find still no operation of actuator with demand on/off? The two orange cables supplying syn' motor were removed and a voltmeter was placed on actuator terminals to find on demand only 170volts not 230volts? Would this likely to be a fault on the actuator circuit board as this only looks a basic circuit comprising of 2 resistors, 2 diodes and a micro switch to me not a lot to go wrong? Or is it more likely to be programmer??? If anyone can help brilliant, I just do not fancy purchasing incorrect part as these mid position valves are quite pricey. Many thanks Tony