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vern
Correct Derek its the fan relay on the board, now upgraded on replacementsWhen the i juniors lock out, occasionally, and with no particular pattern, run the heating for around 15 minutes, take off the combustion cover, open a hot water tap and see if the fan stops, fairly common fault but a swine to catch if you dont know it, the fault lies with the board and the aps will sometimes have been heat damaged by the flames coming back around the combustion chamber, everything else except the aps is heat resistant and doesnt get affected.