Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Attach U-gauge to burner pressure test point
Disconnect white wires from gas valve modureg and make safe
DHW temperature selector set to MAX
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Set the minimum DHW pressure as per the table by rotating the back nut (9mm) while holding the plastic nut (7mm) in place until the correct pressure is obtained (Clockwise to increase, anticlockwise to decrease).
 
Isolate Mains Power to appliance as per TOP's P4
Refit white wires to gas valve modureg.
Mains power on.
 
Set the maximum DHW pressure as per the table by rotating the plastic
nut (7mm) while holding the back nut (9mm) in place until the correct
pressure is obtained (Clockwise to increase, anticlockwise to decrease).
 
Notes:
Orientation of gas valve may differ.
Recheck pressures once adjustment is complete.
When U-gauge is removed test point should be checked for gas tightness.