GAS - Flue Systems
Gas stoves have been designed to operate in a wide variety of installation situations. So, whether
your property has a conventional stone or brick built chimney, one of the modern, pre-cast concrete
chimneys or even no chimney at all, there is a good chance you will be able to enjoy all the
pleasures of living flame warmth at the turn of a switch. The terms "conventional" and
"balanced" describe the way the stove receives its air supply and exhausts its products
A conventional flued stove utilises a flue which needs, if not an existing chimney one
of a similar height. The products of combustion include water which must be kept hot enough to
prevent it condensing within the flue, and because so little heat is lost to the flue, whatever
chimney is used it will need to be lined with a liner approved for gas to maintain the flue
temperature. The air supply for the stove comes from the room in which it is installed and as with
all gas appliances special provision may need to be made for a permanent air supply.
A balanced flue system utilises a double concentric pipe, the inner one taking away the products of
combustion and the outer one bringing the air supply to the stove. This system allows a gas stove to be
installed where no flue exists, and because the flue system needs very little vertical height to
operate, it is often possible to route the flue through the room wall to the outside. With all the air
necessary for combustion being supplied through the outer pipe directly from the outside, the room
in which the stove is installed needs no ventilation specifically for the stove.
1. Closure Plate and Spigot Extension
This is a flue system suitable for homes with existing conventional chimneys in which an
airtight, steel closure plate is fitted over a fireplace opening or Class 2 pre-cast starter block and a short
piece of flue extends from the back of the stove, through the plate, into the chimney. The products
of combustion are carried up the chimney by natural convection.
2. Rigid or Flexible Metal Flue
With this flue system rigid metal tubes, or a combination of rigid and flexible metal tubes,
extend vertically directly from the stove to the outside of the property. This may be either
straight through the ceiling or roof with the flue pipe exposed, or by using the channel of
a chimney or a studwork enclosure. The products of combustion are carried up the chimney by
3. Balanced Flue
Where a room has no chimney then a balanced flue can be a practical option. The flue consists
of one tube inside another. The outer tube brings air into the stove for combustion whilst the
inner one emits the products of combustion.
A - Rear Outlet
B - Top outlet/up and out
C - Top outlet/vertical
D - Top outlet/vertical with offset
4. Powered Flue
Where a room has no chimney then a Powered Flue is the answer. It is a special extractor unit
which attaches to an outside wall and removes the products of combustion, along rigid metal pipe,
by fan action. Generally the flue pipe can be of longer lengths than with a Balanced Flue and can
also include a number of 90° bends.