What to check if a boiler is operating but there are fumes or odours?

If an oil boiler is working but there are fumes or unusual odours, a heating engineer should check the following. Please note, it is important to always isolate the electricity supply to the boiler before working on the boiler. 

Boiler works but fumes and it puffs during starting (conventional flue system)

• Check the condition of the chimney - ensure it is not blocked and is high
  enough to produce the required draught.
• Check that there is an adequate air supply near the burner and that a kitchen fan is not drawing products out of the burner.

Boiler works but there are oil odours

• Check all the fuel line connections and remake as necessary.

Boiler works but the combustion fumes smell

• Check the boiler cleaning cover and seal are correctly fitted.
• Check the burner is correctly fitted onto flange.
• Check the flue is correctly sealed into flue outlet of boiler.
• Check the condensate pipe and trap are operating correctly.