Flexible Flue
All indoor gas geysers (Type B and C) must be installed with a flue. If an Indoor geyser is installed outside it still needs a flue.
Flexible flues have an adjustable length while solid flues come in predetermined lengths of either 300mm or 600mm. Use an exhaust box to close off the flue hole preventing birds from nesting in the flue (see flue guide)
In extreme weather areas, outdoor gas geysers (type D) can be installed with a flat roof weather box to protect the flame from blowing out. These weather boxes have no ventilation so a flue must be installed to prevent overheating and potential damage to the appliance.