Test flue flow to ensure removal of products of combustion.
For a Landlords Safety Record Inspection, a tightness test of the full system should be added to the above.
Check standing and working pressure if test points available.
Check for satisfactory provision of all necessary ventilation.
Check satisfactory operation of all the flame failure devices
Check burner pressure / gas rate against manufacturers data plate.
Check for physical stability, presence and effectiveness of stability brackets (where appropriate)
Investigate any evidence of unsafe operation and report to a responsible person. An appliance can not be deemed as having been checked, until the above has been completed.