Ed Sirett wrote:


Sounds like the lever is bent (or some other trouble) so that after the
valve has correctly opened it does not shut of it's own accord.

The honeywell valves switch on at the end of the travel (beyond the manual
latching position) other make(s) switch on before the manual latching
position.

You might have a sticking valve on the plumbing side.
You might have a defective valve actuator.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

Thanks
the motorised valve is a Drayton ZA5/679-2 Zone Valve
do these valves/actuators often have problems?
cheers
Bole