I am preparing to service my magnaclean and lots of advice to isolate the electric supply to the boiler to stop boiler firing up while carrying out servicing. When I mentioned this to the company who installed my boiler
(which is a Wocester 37 CDi) the advice I was given is that electrical isolation can sometimes upset boiler settings and it is better to just turn down water and central heating temperature settings to minimum.
Can someone tell me which is correct? Thanks
Trev