%IMPORTANT:%%Problems'caused'by'improper'installations'are'not'covered'by'the'manufacturer’s'warranty.''
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IMPORTANT:%%Undersized'and'improperly'installed'duct'pipe'and/or'other'ventilation'components'will'cause'excessive'static'
pressure'(air'resistance),'that'may'result'in'rattling,'vibration'and'air'buffeting'noises,'as'well'as'inadequate'ventilation.'
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1. Building%Codes%
BBQ'Hood'Ventilators'should'be'installed'by'qualified'technicians'familiar'with'state'and'local'building'codes.'
'
2. Duct%Pipe%and%Fittings%(Elbows,%Transitions,%Roof%&%Wall%Caps)%%
a. Use'round'or'rectangular'rigid'metal'duct'only.''Where'possible,'use'round'duct'as'it'creates'the'least'amount'of'
static'pressure.''DO'NOT'use'flex'duct.'
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b. All'duct'sections'and'fittings'(EXCEPT'DAMPERS,'per'Section'4),'should'overlap'and'be'connected'with'at'least'3'–'4'
equally'spaced'screws'and'wrapped'tightly'with'2'–'3'layers'of'Aluminum'Foil'Metal'Duct'Tape.''This'type'of'duct'
tape'is'more'durable'than'traditional'cloth'duct'tape.''DO'NOT'use'butt'joints.'
'
c. For'best'air'flow,'elbows'and'pipe'size'transition'fittings'should'not'be'directly'connected'to'one'another.''Where'
possible,'always'include'at'least'15'inches'of'straight'pipe'between'fittings.'
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3. Duct%Pipe%and%Fitting%Sizes%
IMPORTANT:%%No'portion'of'any'length'of'duct'pipe'or'fitting'should'be'smaller'than'the'discharge'port'of'the'ventilator.''
This'is'very'important'because'any'type'of'restriction'anywhere'in'the'ventilation'system'will'cause'increased'static'
pressure'(air'resistance),'that'may'result'in'rattling,'vibration'and'air'buffeting'noises,'as'well'as'inadequate'ventilation.''
See'Duct%Sizing%Chart%and%Area%Calculations%section'for'more'detail.'
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Duct%Runs%–%Length%
a. Configure'the'ventilation'duct'run'to'be'as'short'and'as'direct'to'the'outside'as'possible.''Minimize'the'number'of'
elbows'and'transition'fittings'used.''Complex'or'long'runs'should'be'reviewed'by'a'qualified'installer.'
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b. No'portion'of'the'ducting'should'be'run'so'that'the'exhaust'air'flows'downward.''Since'exhaust'heat'rises,'forcing'
the'air'to'flow'downward'will'cause'increased'static'pressure.''As'previously'mentioned,'improperly'installed'duct'
pipe'will'cause'excessive'static'pressure'(air'resistance),'that'may'result'in'rattling,'vibration'and'air'buffeting'noises,'
as'well'as'inadequate'ventilation.'
'
c. Duct'runs'for'1200CFM'ventilator'models'should'not'exceed'35'linear'feet'with'two'90-degree'elbows'and'two'45-
degree'elbows,'a'damper'and'a'roof'or'wall'cap.''Longer'runs'or'additional'elbows'will'result'in'decreased'
ventilation'performance.''Each'90-degree'elbow'is'the'equivalent'of'6'linear'feet'of'duct'pipe;'each'45-degree'elbow'
is'equivalent'to'3'linear'feet'of'duct'pipe.'
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d. Always'run'ventilator'ducts'to'the'outdoors.''DO'NOT'terminate'a'duct'into'an'attic,'basement,'garage,'crawl'space'
under'a'house,'a'chimney,'other'ducting'or'an'enclosed'room.'
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4. Dampers'
%IMPORTANT:''DO'NOT'USE'ANY'TYPE'OF'DAMPER'IN'A'BBQ'HOOD'APPLICATION.'
'
In'ventilation'systems'utilizing'a'roof'cap'or'wall'cap'with'a'built-in'damper,'remove'it.'Dampers'are'unnecessary'and'will'
cause'increased'static'pressure'(air'resistance),'that'may'result'in'rattling,'vibration'and'air'buffeting'noises,'as'well'as'
inadequate'ventilation.%