valiant thermocompact boiler

[ZIGGY786]

Hi mik try that but still same

 

[twgas]

Boiler still fires with all three grey wires disconnected?

 

[simond]

if you take the wire out from number 3 on the pcb board the pump over run stops .


can a new honywell valve be faulty as it was only changed 3 weeks ago

This is an interesting one. Terminal 3 on a Thermocompact is linked to the mains LNE via the overheat stat and mains switch.

Terminal 3 should be the live feed to all your central heating controls, and then the live should be returned to terminal 4 for the boiler to start.

Pump overrun is only likely to be terminated when there is no voltage on the main LNE connections to the boiler. What you connect to 3 and 4 should not stop pump overrun functionality.

Therefore, I think you have no permanent live supply to the boiler.



As an aside, your boiler is well out of warranty and there is no way Vaillant are coming and changing valves etc. What you have there is an insurance company numpty parts changer.

I would imagine you took the Vaillant 'Domestic & General' extended warranty offer? Unfortunately the engineers that work for insurance companies are usually not the brightest spanners in the toolbox. Apologies to the small minority that do not fall into this category.