My old boiler is starting to play up. When running dhw the pump runs but ignition refuses to kick in. I then have to turn on the c/h ( which takes about 5/10 minutes to ignite) and only then does the dhw work okay. Water pressure is okay and have checked the manual fault finder page. Any ideas?? The wife is giving me grief!

Neil, June 2011

diaphragm in DHW flow valve likely to need replacing
if diaphragm shredded it cant operate DHW microswitch
straightforward repair
cheap parts
easy fix

manwithnoname, July 2011