Hi all the boiler works perfect most of the time and then the light comes on code 60 which means the ionisation pcb faulty. Why will it work sometimes only. By the time i call to check it its goinf ok. When it locks out it may stay that way for 24 hrs and then work fine. This happens on both hot water and central heating. Should i just replace the pcb. Im not to familar with this boiler. All replys appricated