when the programmer has switched off , the boiler continues to run (until I switch it off manually) we have changed thermostat,pump,programmer and most other items, other than the boiler. We have had 2 heating enginners and 1 electrician, they all say it can't be the boiler . any Ideas .

Bill (in despair) Camberley , Surrey., November 2013

obviously you need to trace why the boiler is getting a feed when it shouldn't, the first thing that comes to mind is a zone valve, if there are 2-2port valves the orange wires should not be live when both valves are closed,try disconnecting them ( the orange wires ) and powering up to see what happens,as I find in lot of cases like this the supposed experts do not apply any logic to the fault finding process I mean why change the pump it has nothing to do with firing the boiler up.If the fault persists you need to trace why it is getting a fire up signal, from the boiler back to source,not hard job to somebody who knows what they are doing

toptrish, November 2013