no hot water from ch system

[AnonymousImport]

pumped system works ok on heating side. two channel controller 5 years old fully electronic. boiler does not fire up when water side of controller switches on ( with an audible click and a red light.)
Hot water can be obtained by manually opening the motorised valve. I suspect the hot water tank thermostat is preventing the system operating. Can this be tested? Am I on the right lines?

 

[AnonymousImport]

it is probably the motorised vale which is faulty

 

[AnonymousImport]

Sounds like motorised valve - replace the head only - power off replace coloured cables in same places as existing.