gloworm ultimate 40ff no c heating

CH stopped working in spring. Only just looking at it. A year previously had 3 way valve and Pcb replaced (pcb was faulty). CH light on on lifestyle control unit. Thermostat in hall clicks. No response when 3 way manually operated. Pump not running, but no power getting through to it! Any ideas of cause? Thought may be thermostat in hall (acl Drayton)even though it clicks, but how do I check it? Any ideas please. Thanks. Colin

 

Thanks for your reply. Oh yes, hot water perfect.

 

Thanks for your time, may try ordinary switch at thermostat end connection across live and other wire but excluding common. Boiler should then fire up to prove that stat is at fault? 3 way is only 18 months so should be ok.