I have a client with a Vaillant combi-boiler - approx up to 10 years old. The problem is that the boiler doesn't always fire when a hot tap or the shower is turned on. I have adjusted a microswitch but it's just started doing it again. They can usually get it to fire by switching it off and then back on again while the water is running - which seems a bit odd...
Anyway, any advice on sorting this issue?
Anyway, any advice on sorting this issue?