On Sat, 21 Aug 2010 23:17:33 +0100 Spamlet wrote :
"Change the motor (for Honeywell, they recommend you get a Honeywell
motor as it they are more robust as their valves can remain open (i.e.
powered) to CH if that was the last demand, even if demand has now
ceased, therefore more wear on the motor)."

Is this really true? I would have thought that a microswitch would
stop the motor when it has reached position.

No, two port valves are spring loaded to close. When power is applied to
the motor the valve opens; when it reaches the limit stop the motor
stalls. The microswitch in the MV is to switch the boiler on and off

--
Tony Bryer, Greentram: 'Software to build on' Melbourne, Australia
www.superbeam.co.uk www.eurobeam.co.uk www.greentram.com