worcester heatslave 15/19?

things to check
the dial on the front of the boiler is there a click as you turn it
if not replace it
is there 240 on the room stat going onto the pcb it is marked, top middle of the board if not your timer or room stat has gone
when you turn the heating dial on the front of the boiler does relay RL3 activate possible pcb.
and lastly is there 240 to black cable on diverter valve if yes then diverter valve has gone or brass wear seized

plumbbob
December 2010

Had exactly the same problem, with the same boiler, diverter valve was stuck on mine.

handyandy
November 2010

Same problem, if you find out let me know. I'll do likewise.

Not Hot Hank
October 2010