Atmos Energy HE26 - Manual (Page 30)

5.6 Roof outlet prefabricated chimney
Appliance category: C33
When there is little space in a shaft, a roof outlet through a prefabricated
chimney may be necessary.
The prefabricated chimney must comply with the minimum lengths
shown. The supplier must guarantee the proper operation of the
prefabricated chimney with respect to wind attack, ice formation, rain
ingress, etc.
In view of the different models and requirements, the prefabricated
chimneys must be adjusted to the local situation: a gas certificate is not
required.
CAUTION
The connection of the air supply and the flue discharge
between the appliance and the prefab chimney must be
made in pipes of diameter 80 mm.
Maximum pipe length
See §5.5.5
Mounting of prefabricated chimney
The outlet can be made at any place in the pitched or flat roof surface.
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