Flue Restrictor Adjustment Mqrb4436 & Mqrb5143 - Marquis Infinite MQRB4436N Installation Instructions Manual

Flue Restrictor Adjustment
MQRB4436 / MQRB5143 Only –All Models
The Flue Restrictor is located in the top of the
Firebox in front of the Flue Opening.
For vertically vented installations it is necessary to
use the Flue Restrictor. Restrictor is set fully open
from factory for short horizontal and vertical runs.
To adjust the Flue Restrictor:
Fig.1
1. Remove the [2] DT screws in the Flue Restrictor. Also
remove the [2] screws at the front of the Flue (Fig.1).
2. Rotate the Flue Restrictor 180°. (Fig.2). Place the Flue
Restrictor over the Flue & start the [4] DT screws in the
screw holes.
Fig.2
3. For Vertical Venting 20-30 feet in height, the Flue
Restrictor should be open 1-7/8" from the back of the
Flue (Fig. 3).
4. Between 30/40 feet: Set Restrictor in conjunction with
the number of 90° elbows.
1 to 2 elbows 1-3/8"
•
2 to 3 elbows with offsets 1-7/8"
•
Fig.3
5. For Vertical Venting 40 feet or above in height, the Flue
Restrictor should be open 1-3/8" from the back of the
Flue (Fig. 4).
Fig.4
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