18sxi F1 F4 fault?

F1 and F4 are both gas related codes, nothing to do with water pressure as such. Set pressure of system to 1 bar, when cold, it will go up when hot, returning to 1 on cooling down.
F1. No gas, Insufficient gas, Incorect gas valve adjustment, Electronic Ingnition lead defect, Electronic Ignitor Defect, Check Air inlet duct, Check connections to ignitor unit, F4 As F1.

SD
October 2012