Many thanks for the comments. My knowledge is limited but if I understand you correctly there should be a residual voltage when the boiler is off which rises when the timer is activated. There is no voltage across the orange wires in either instance. The timer activates the pump so does this...
Had an engineer out last week when pilot light wouldn't stay on. He found the overheat cut out switch had activated but couldn't find anything that might cause this.
All ok until yesterday when heating & water didn't come on. Pilot light was off so re-lit. Stays on but boiler won't fire up...
