Thanks b, It's the Worcester Digistat T45 - i've googled and the manual found here:-
http://www.worcester-bosch.co.uk/cache/file/135/24-hour-digistat-instructions.pdf
Having read through it(sis u do the same)think we can try out and see where we get to. Looks pretty straightforward (famous last words!)
For info - boiler worked throughout the night - good news - when shower run this morning the system went down - checked the condensate pipe and u guessed it - it had frozen up again (-8 deg last night)- went through procedures as before and system restored again -
for info Spoke to our Service Engineer - and was advised that in hot water mode the boiler will be working at full output so the more condensate whereas in norm central heat this will be much less.
Interesting to know that as a gas installer they are not allowed as such to defrost condensate with hot water for quick fix - but required to address problem - v good practice - so will be increasing the 15mm unlagged pipe that was not installed at a downward angle through wall with larger dia - 1 1/4 inch as advised.
Phew! there must be a lot of condensate pipes freezing up at the moment.
Thanks again b, service gonna be carried out next week.
Hope anyone keeping track of thread has found helpful.
Think this site - as good as it is - requires a FAQ section - with boiler types and common faults / answers. Think we've advised on about 20 now - and its the same old - but v interesting to read questions/answers on others too.
Regards and thanks v much
eddie
eddie
January 2010