Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Gain access to PCB (use Insulation Mat as required)

Observation:

Standard 24V controls are fitted to connections 6 & 7 on X4.
OpenTherm 24V controls are fitted to connections 11 & 12 on X4.
Mains (240V) controls are fitted to connections 1 & 3 on X2.
Please select which type of external controls are fitted to the appliance.