Hi hope someone can help .My vokera 20/80 has started shutting down completely when the radiator thermastatic valves close. The boiler makes angry grumbles and the shuts down inc turning the pilot out.after a short rest it will fire up again but the sequence is repeated. appreciate help. Paul.
thanks

Edgertonman....., November 2009

sounds like a circulation problem, blocked bypass, lazy pump, it cant get rid of the heat quick enough hemce the banging and out on o/h

ste, November 2009