Drolet Heat Commander Installation And Operating Instructions Manual page 30

FAVOUR THE USE OF RIGID DUCTS BECAUSE THERE ARE LESS RESTRICTIVE TO
AIR FLOW.
- The maximum run of a main duct is 35' (10.7 m). It must be reduced from 6" (152 mm)
to 5" (127 mm) after 20' (6.1 m) or reduce the main duct by 1" (25 mm) at every two
secondary duct outputs.
- The maximum length of all the main ducts is 180' (54.9 m).
- The maximum run of a secondary duct is 10' (3 m).
- The maximum length of all the secondary ducts is 100' (30 m).
- The finishing grill at the output of a secondary pipe must be made of metal.
- Have a maximum of three secondary outputs per duct.
Note: figure for illustrative purposes only
For proper static pressure and heat distribution; the total area of secondary duct outlets must
be equal or slightly less than the total area of the outlets used on the distribution plenum (B).