Set Appliance State:

CH Demand
Access the status codes by pressing the - button for at least 5 seconds until it begins to flash S and a number alternately
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Check that the number corresponds with the correct status.
Pump overrun is indicated by S.7
Note:
S.5 indicates combined fan/pump overrun, this should only occur for around 20 secs as the fan will then stop and the status reverts to S.7 (pump overrun only)
Use this link to see a full list of STATUS CODES