Osburn OB04002 - Manual (Page 78)

Stratford Fireplace Installation and Operation Manual
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The hot air gravity distribution kit must be installed respecting the following:
1. Remove the plates closing up the 8" dia. holes on top of the fireplace. Then, cut the
insulation in order to obtain two 8" dia. openings. Insert the ducting into each opening and
fix it in place using the 6 steel brackets supplied (3 for each duct).
2. Maintain at least a 2" (50 mm) clearance between the ducts and the firestop; the required
hole size for the hot air grilles (outlet) is 8¼" × 8¼" (210 mm × 210 mm).
3. The maximum number of elbows in a run of duct is two.
4. Maintain at least 10" (254 mm) clearance from the outlet grille framing to a combustible
ceiling, side wall or mantel.
5. When passing through a combustible wall or floor, a firestop must be installed at the wall or
floor penetration. The hole size must be in accordance with the duct manufacturer’s
instructions.
6. Do not connect the hot air ducts to a central heating system. Malfunction of the heating
system’s fan will cause the fireplace to overheat.
7. Do not use insulated flexible ducts as they may overheat.
8. Do not use tees or any other components than the ones specifically listed here.
9. All ducts must extend upwards or horizontally. Never route the ducting downwards.
10. The hot air outlet grilles must be installed with the louvers pointing downwards in order to
prevent overheating adjacent ceilings.
11. Always install the two outlet grilles when using the hot air gravity distribution kit and
blocking the upper louver of the fireplace.