had an ultimate 50ff which hadn't been used during the summer so the pilot jet was blocked. also heating hadn't worked for ages (bloke lives on his own & spends all spare time in pub i think.)cleaned pilot jet, replaced seized & corroded mid pos.
turned boiler on for safety checks etc & all ok until i turned it off at timer.
still running. checked s/l & found 120v ac with timer off.
disconnected s/l from pcb choccy block & turned on electrics & boiler fired up.
removed timer & boiler still firing up.
replaced pcb (5 wire type) still fires up when no demand. substituted mid pos head (backfeed) no different.
completely stripped wiring centre & re-wired from scratch.
now s/l 0v ac when no demand but boiler still fires up all the time. replaced boilerstat/p/orun stat assy. still fires up. tried another pcb (new) boiler still fires up. spoke to glow worm technical (after waiting in queue for 24 mins. "it's the pcb mate !)
have i done something wrong here or am i a failure ?
