Hi, I went to service a 3 year old Baxi Duotec today, The heating has been off for 6 months. The hot water has been working fine untill I turned on the heating to do a CO2 analysis. The boiler fired for a few seconds and then E168 flashed up and the boiler stopped working. Now the hot water causes it to fault to E168 as well.I called Baxi tech and was told to checked pump,gas valve and spark generator all were ok. They told me it was most likely the pcb.. Has anyone else had this problem 😕