you may have a diverter valve fault,or heat exchanger needs cleaning expensive repair !
With an old swift flow combi . your best bet is to replace it with a new more efficent boiler
jts plumbing
September 2009
Sounds like the Flow switch has failed
www.elanar.co.uk
September 2009
Automatic Answer
While you wait for answers, we may have found some information which could help you.