I have a greenstar boiler its 16 mths went out today blue light flashing checked the condensation pipe was frozen have cleared it out the flue looks ok but im 72 years old its snowing and its bitter

Check gas & power supplies,if all ok check pcb

This will show that you have a water leak on your boiler or pipe work .

http://www.worcester-bosch.co.uk/homeowner/literature/gas-boiler-literature/greenstar-15ri-literature. Hope this helps :)

If you are talking about the damper flap on the flue pipe. You have to go to a heating supply and buy a new flue that is already attached to a section of new pipe and fit it together. I'm not sure if your flue is free flap type of arm driven. British gas is trying to make a buck off you . Call a regular boiler repair man if you don't feel comfortable doing it your self.. Mine came apart at the hinge. The pin came out..I replaced it with a wire brad (nail) and it works just fine.

Google Alpha boiler you should be able to down load a online manual with a ff chart in it . which should have codes in there for flashing lights .

water vapour is one the main products of combustion of gas. With a standard efficiency boiler, upon initial heat up when the flue is cold this vapour can condensate on the inner wall of the flue but should stop once the flue heats up, to stop this condense dripping back on to the heat exchanger the flue should be tilted towards the outlet and thus on initial heat up water can drip from the flue. with high efficiency (condensing) boilers, condensation will occur in the flue and secondary heat exchanger during normal operation, dispense of this condensate is accommodated for in the boiler and therefor the flue should be tilted towards the boiler, if not the flue will drip constantly.

Basic checks:-
water pressure in boiler
gas supply on
Turn boiler on then:-
does the fan come on - u can hear this at the top of boiler
does the gas valve click on
has there been a burning smell near the lower front [check the pcb]
check the co-axial flue is ok with no gaps between inner & outer [rare but not unknown]
If it's a condensating boiler check the condensate outlet tube for ice blockage especially in current weather

your condensation pipe may be frozen get a hairdryer on it or a hot kettle that should sort it thats the whit pipe on the left usualy plastic

http://www.worcesterbosch.com/Go there see if you can get some help.