No CH

[nzmanc]

When I call for CH the boiler does not fire up. HW is fine and when on all the rads upstairs get hot. Its an S plan system with the pump on the return. The pipes are hot past the valve that should control the CH. Would I be right in thinking this valve is passing and not talking to the boiler and so needs replacing. Im also thinking there may be an airlock on the drops to the lower rads hence why they arent heating. The system is microbore and was switched off for a couple of months. any thoughts?

 

[Arrgee]

is the pump running? and on an splan the upstairs rads shouldnt heat up on hot water.
If they are Honeywell valves you should have a lever at the end the wire comes from if the lever moves freely without resistance it means the valve is opening ok and when you turn off the room stat the one for the heating should spring back to closed