Lennox Merit Plus Series Installation Instructions Manual page 14

LENNOX HEARTH PRODUCTS • MERIT PLUS
Vent Restrictor Installation in Top Vent
Systems
Note: When top venting the fireplace, the top
vent flue restrictor MUST be installed.
Figure 19
1. Remove the 2 top front screws and loosen
the 2 top rear screws of the rear solid cover
plate (Figures 19 and 20).
2. Install the top vent flue restrictor by
sliding the two notches in the top vent flue
restrictor (Figure 20) under and behind the
two screws loosened in the previous step,
and then tighten the screws (Figure 21).
Loosen screws.
Top Vent Flue Restrictor
Figure 20
Tighten screws.
Figure 21
14
DIRECT VENT GAS FIREPLACES (MPDP35/40) • INSTALLATION INSTRUCTIONS
®
3. Bend the top vent flue restrictor FORWARD
and UP (Figure 22), and secure with the
other 2 previously removed screws (Figure
23).
Figure 22
Figure 23
When top venting, remove the outer top
knockout and gasket from outside the unit
(Figure 24).
TOP VENT SEAL AND COVER PLATE REMOVAL
WHEN USING THE TOP VENT
KNOCKOUT
(OUTSIDE UNIT)
GASKET
CABINET TOP
TOP VENT
FIREBOX TOP
VENT
COVER PLATE
(INSIDE UNIT)
CROSS SECTION
Figure 24
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
IF TOP VENT VERTICAL VENT LENGTH
IS 8 FEET OR LONGER:
Before attaching the first piece of venting
pipe, install the U-shaped vent restrictor
into the top vent collar from outside the
unit (Figure 25). The U-shaped vent
restrictor is held in place by friction.
Note: An elbow may NOT be directly
attached to the fireplace top vent col-
lar. A minimum of 1 ft. of vertical vent
pipe must be attached to the top vent
collar before installing any elbow.
U-SHAPED VENT RESTRICTOR INSTALLATION
Installation of the U-shaped vent restrictor
is required in top vent applications with vent
runs over 8 feet.
Install the vent restrictor from outside the
unit in the inner fireplace collar of the top
vent outlet, oriented as shown below.
U-shaped
Vent Restrictor
Inner
Fireplace
Collar
Figure 25
Select Venting System
(Horizontal or Vertical)
With the appliance secured in framing, determine
vent routing and identify the exterior termina-
tion location. The following sections describe
vertical (roof) and horizontal (exterior wall) vent
applications. Refer to the section relating to your
installation. See Pages 36 and 37 for a list of
approved venting components.
COVER PLATE
SECURING SCREWS
(TOP VENT)
Appliance Top
Vent OUtlet