Set Appliance State:

WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Enter the appliance parameter setting mode, click here for a guide on how to do this.
Check parameter 2-4-7, this is the appliance low water pressure device setting, this can change if the appliance experiences electrical supply fluctuations and can also be set incorrectly after fitting a brand new PCB causing a 108 or 109 error code.
On this appliance the parameter 2-4-7 should be set to 1, if it is set to a different value it should be changed to 1
Once the parameter has been set correctly exit the parameter setting mode.
Apply a CH demand and see if the 108 or 109 error code returns.
Note.
It is very important to apply a CH demand as the error code will only return with a demand.