Hot water but no heating?

Helps to say the make & model & type of boiler.

Try turning off electrical power to boiler - see what happens after 30 secs off

Try asking timer programmer to make hot water and central heating at same time (run off some hot water from the tap) and see what happens

Try asking timer programmer to make hot water only
Ditto central heating only

Put in new question with more info - somebody may be able to assist you - but you may well need an engineer to call.

Do not "blame" the service - things can go wrong at any time.

Good luck...

Peccavi
March 2010