central heating greenstar 30 si Worcester Bosch

[dale7601]

Ive got a greenstar 30 si (5yr old).
Hot water is perfectly fine (although with no blue light), -but we have no heating. -The blue light is not on for c/h or h/w at all but does work when powered off or reset (confirming the light itself works)
Occasionally the pilot light comes on for a few seconds and steam can be seen outside when on c/h but then stops.
Ive found a fault list on net but states the blue light should be on.... :(

[dale7601]

update, i can get the blue light to flash five times ? and when its in this mode (spanner light and blue light flashing, the heating works!!!! - when set to normal - it goes off :( :(

[The Builder]

Needs investigating by a good boiler guy, Dale. It could be a faulty circuit board; diverter valve; or maybe just a cheap thermistor replacement.
Too many possibilities to say for sure.
Nothing DIY I'm afraid.