Central Heating (boiler) Issue- Valve Actuator (3 way valve)


6 Dec 2005
Reaction score
United Kingdom
The actuator valve which determines whether the combi boiler is heating for hot water or the central heating system is not working consistently; basically the valve actuator (honeywell VC6012) sometimes does not switch over to heat the water when there is demand for hot water and then sometimes it does not switch back.

My first thoughts and the plumbers also was to change the motorised actuator valve this did not resolve the issue.

Scenario – heating works ok, the majority of the time but sometimes the valve will not switch over to water heating unless the motorised actuator valve is given a slight twist.

Please could somebody provide an explanation of why this motorised actuator valve is not working.

Because we have replaced the actuator could it be lack of electrical signal, how does it know when to change.

When the issue occurs- if I take the motorised actuator off and fix it straight back on again, it works? then the problem reoccurs later !

Any technical explanation or constructive advice would be greatly appreciated

Additional Info

Combi Boiler Model

(Actuator refereed to in the manual as - three way valve)

Actuator – Honeywell VC6012 (Double Insulated Actuator)

Thanks in anticipation.

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