Xo XOI22SC Manual page 8

THIS HOOD IS DESIGNED TO USE A 6" ROUND DUCT -
IT MAY BE TRANSITIONED TO A 3-1/4" X 10" RECTANGULAR DUCT
NEVER REDUCE DUCT SIZE. UNDERSIZED DUCTING SEVERELY RESTRICTS AIR
FLOW AND HARMS PERFORMANCE.
(Example: the area of a 6" Duct is more than TWICE that of a 4" Duct)
KEEP DUCT RUNS AS SHORT AND STRAIGHT AS POSSIBLE.
AVOID USING FLEXIBLE METAL DUCTING IF RUN IS LONGER THAN 6'.
NEVER USE PLASTIC DUCTING.
USE SMOOTH BORE METAL DUCTING.
MINIMIZE THE NUMBER OF FITTINGS (see chart).
WHEN YOU MUST USE FITTINGS, TRY TO SEPARATE THEM WITH SECTIONS OF
3' OR MORE OF STRAIGHT DUCT.
ALWAYS FOLLOW THE MANUFACTURER'S GUIDELINES FOR THE COOKING
EQUIPMENT YOU ARE VENTING.
IF MAKE UP AIR CONTROL DAMPERS ARE REQUIRED, POSITION THE SENSOR
IN A STRAIGHT RUN OF DUCT IDEALLY WITH 3' OF STRAIGHT DUCT BETWEEN
EACH SIDE OF THE SENSOR AND A DUCT FITTING. REMEMBER TO INCLUDE
POWER AND CONTROL WIRING FOR THIS IN YOUR PLANS.
ADHERE TO ALL LOCAL BUILDING CODES AND ORDINANCES.
US E T HE WO RK SH EE T T H AT FOL LOWS TO HE L P C A LCU L ATE T HE
TOTAL EQUIVILENT FEET OF YOUR DUCT RUN.
TOTAL EQUIVILENT FEET SHOULD BE LESS THAN 100'.