potterton ep20001 programmer wont light hw?

In one condition the signal to fire up the boiler comes from the programmer via a micro-switch in the three port valve - I think (but am not certain) that when CH only is called for the motor drives the valve to the correct position and in doing so a micro-switch is actuated and a "boiler please fire up" signal is sent to the boiler on an orange wire - if the motor doesn't drive or the switch is not actuated then the boiler will not light.

To view the wiring use Google Images
Enter 3 way valve wiring diagram

Good luck....

Peccavi
February 2013

update on situation due to frustration hit the 3 way valve and the programmer and hw light has come on. Now works independantly after 2 hours!! not technical but effective.

jake
February 2013