phase4.mod14.flue config.

When installing a balanced flue through a wall containing cavity insulation, a gap must be provided between the outer duct and the insulation of a minimum of:

• 15mm.

• 20mm.

• 25mm.

• 30mm.

An appliance fitted to a vertex flue system draws its combustion air from:

Where a single wall flue pipe runs through a roof space it must:

• Be replaced with double wall flue.

• Be insulated.

• Only be used on gas fires.

• Need not be supported.

When a boiler is fitted to a vertex flue installation, information regarding the specific ventilation requirements within the loft can be found from:

• The HSE.

• BS5440-1

• The manufacturers instructions.

• The Gas Safety (Installation and use) Regulations.

When a flexible flue liner is installed within a brick built chimney, the space between the flue liner and the chimney:

• Must be sealed at the bottom only.

• Must be sealed at the top only.

• Must be sealed at top and bottom.

• Need not be sealed at top or bottom.

When installing twin wall flue pipes, the male end of all sockets must be installed: