my programmer will not light up the HW side of the display after a power out. If I select hw it switches the central heating on and lights up ch but still does not light up hw though the water has got hot. When i turn the power off the 3 way valve moves possition so i believe this is working I could be wrong . A friend said my backup battery was no use but would this affect the programmer when the power was back on. Any ideas

jake, February 2013

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