Flue Systems for Oil Flashcards

What is the purpose of a flue terminal guard on a low-level balanced flue?

Answer: To prevent people from being burned by contact with the hot terminal

A terminal guard is required when a balanced flue terminal is below 2 metres above ground level in an area accessible to people. It prevents accidental contact with the hot terminal surface, which can cause severe burns.

What is the effect of a blocked or partially blocked flue terminal on an oil appliance?

Answer: Combustion gases cannot escape, causing spillage into the room and potential CO poisoning

A blocked terminal prevents combustion gases from escaping. This causes back-pressure, leading to combustion gas spillage into the room, incomplete combustion, and dangerously elevated CO levels. Common causes include bird nests, leaves, and ice.

What must be done when converting a chimney previously used for a solid fuel appliance to an oil-fired appliance?

Answer: The chimney must be swept, inspected, and lined with a suitable oil-rated flue liner

Before using an existing chimney for oil, it must be swept clean of soot and creosote, inspected for structural integrity, tested for gas-tightness, and lined with an appropriate oil-rated stainless steel liner to protect against acidic condensates.

Where should a flue gas spillage test be performed on a conventional flue oil appliance?

Answer: At the draught diverter opening with the burner running at stable temperature

The spillage test is performed at the draught diverter (draught break) while the burner is running at stable operating temperature. A smoke match or pellet is held at the opening to confirm gases are being drawn up the flue.

What is the required flue terminal position in relation to a pitched roof ridge?

Answer: The terminal must be between 600mm below and 1000mm above the ridge level

The terminal should generally be positioned so that it is not more than 600mm below the ridge of a pitched roof (to avoid downdraught) and ideally at or above ridge height. Specific positions depend on the roof pitch and terminal distance from the ridge.

What material should be used for the flexible flue liner in a masonry chimney for an oil appliance?

Answer: 316-grade stainless steel rated for oil combustion products

316-grade stainless steel is required for oil flue liners due to its resistance to the sulphuric acid formed when sulphur in the oil combines with moisture in the flue gases. Lower-grade stainless steel or mild steel would corrode rapidly.