Help - potterton powermax HE boiler problems

[Steve100]

Anyone know how to stop the pressure from going up and then going to lock out on this potterton powermax HE boiler? It has a error message of E 0.1

Any suggestions grateful.

The pressure gauge cuts out at 4.

 

[BluePlumber]

filling loop valve is passing, pressure is too high, should be 1 bar when cold, drop system pressure, boiler should fire, check filling loop valve and check valve.
next check the expansion vessel, has not de-pressurized or split, if de-pressurized top up to 1 bar, if split either change or install a separate vessel on the system pipe-work