25. Installation – chimney cowls
A properly designed chimney should
need no attachments at the top other than perhaps a basic raincap.
This is what you should aim for.
XXMetal
cowls always become a maintenance chore since they clog up with
soot and have to be scraped clean at regular intervals. And as
they are continuously exposed to the elements as well as hot
acidic flue-gasses, deterioration is inevitable.
XXIf
your chimney smokes persistently on a flat calm day, installating
a cowl will actually make matters worse since you are
introducing further resistance into the flue path. Cowls can
only help to improve matters when the wind is blowing. Therefore
check carefully to see which situation applies.
XXCowls
that rely on rotation including the "granny" and "lobster-back"
type tend to seize up rapidly when exposed to the tars contained
in woodsmoke. The "Aerocowl" pattern is a better bet
since it has no moving parts. The "Aerocowl" is actually
quite cunningly designed since it can not only help prevent blow-down,
but is also useful in situations where chimney draught is excessive
– as is the case in many coastal and island locations.
|
| For product information
on the Aerocowl click here |
|
