Bends
The ideal flue is straight and vertical. New chimneys must not deviate more than 45º from the
vertical, but it is desirable that the deviations do not exceed 30º. Bends greater than 30º are not
allowed in pre-fabricated metal chimneys. In older chimneys bends exceeding 45º may be found
and will degrade flue performance, particularly by allowing soot deposits to accumulate in the
angles. In new flues it is essential to check that no
builders material has been left in the bends.
Flue Gathers
All fires need some type of gather
to channel
the smoke to the base of the flue. If there is no
existing gather then one needs to be provided.
Gathers may be constructed from bricks, blocks
etc or can be a proprietary cast gather or fire chest.
Alternatively the Jetmaster gather may be fitted. In
nearly all cases where a gather needs to be fitted
to an existing flue then the chimney breast will
need to be cut into.
The Jetmaster fire is not a structural unit, although
very robust it is not designed to take the weight
of the flue. Therefore a structural lintel will need
to be provided for clay liners or the use of a fire
chest with built in gather lintel or in the case of pre
fabricated stainless steel chimney the chimney
manufactures recommended fixing brackets or
method must be used.
Installation Using an Existing Flue Gather
If the existing
masonry
gather is to be used to
channel the smoke into the flue from the top of the
fire, it must be smooth and in good condition. The
flue dimensions must be reached at least 200mm
above the top of the fire, where the flue exit is
central, and at least 500mm above the fire where
the flue exit is to one side. The shoulders of the
gather should not be at an angle of more than 45º
from vertical.
Installation Using the Jetmaster Flue
Gather and Adaptors
The Jetmaster Flue Gather and adaptor is a convenient way of achieving the efficient transfer
of smoke from the fire unit to the flue. It may be used bolted onto the firebox and the assembly
slid under the flue as shown in the diagram below. The use of a small plinth as shown in the right
hand example is recommended, as this minimises any ingestion of dust into the convected air.
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Summary of Contents for Standard 16
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