CentralHeating - Mid Position Valve sticking?

[HughJohn]

I have a Lifestyle Mid position valve on my Central Heating system. It has 3 positions - H M W. It seems to work correctly except that when its in the W position and I switch "OFF" the Water on the programmer with Central Heating selected "ON", the valve does not move until I physcally move the valve using the mechanical lever to bring the valve to the M position. The actuator then moves the valve to the H position.

Following Day
On checking the valve operation today, it now appears to be working normally. The WD40 I squirted through the opening (onto the gearing etc) at the indicator yesterday seems to have done the trick. However, thank you for your advise which I will keep in mind for the future.

 

[seco services]

sounds like you have a faulty microswitch or the board inside the valve.

 

[MANDATE]

John! If you need a second opinion, I agree with 'seco' regarding the microswitch.
These type of valves have two microswitches, each like two way switches.
but not wired in the same manner.
With four lots of contacts they cater for.
(a)Live wire (usually white) goes into SW1 and out at 'com' to drive motor until switch is triggered (mid point)
(b) Another wire live when CH in demand(usually 'grey') goes into SW1 also out at 'com' to drive motor from mid point onwards
(c) Live wire, branch off the (white) goes to 'com' on SW2 and out to produce modified voltage to hold valve at mid point if needed.
(d) Same live as above to 'com' but out through (usually orange) wire to power up boiler and pump.(after being triggered)
I've had one problem where burnt/dirty contacts affected (d) above.
I would think you have same type of problem affecting (a).