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P-9
© FANTECH
2016
INSTALLATION DO’S AND DON’TS
INSTALLATION DO’S AND DON’TS
Down
Slope
Figure 3.4. - Backdraft shutters
Butterfly back-draft shutters on a roof unit should be installed so gravitational effect on each leaf is the same.
Down
Slope
Don’t have shutters at 90° to roof fall. The lower shutter must
overcome a greater gravitational effect for even air flow. Also the
top damper may go over top dead centre and not close.
Each leaf has the same gravitational effect when shutters are
parallel with roof fall.
Greater
than 30
o
Less than 30
o
Don’t mount the fan on an upstand or curb with an angle
greater than 30°.
Do ensure the upstand, and therefore fan, is at an angle less
than 30°.
Some fans may require an angle less than 30° or a completely
horizontal upstand - refer to the relevant product page.
P
3.0 ROOF UNITS (Cont.)
Figure 3.3. - Maximum Mounting Angle for Roof Units