Air Flapper Valve Assembly - Lennox G21Q3-40 Unit Information

AIR FLAPPER VALVE ASSEMBLY−40/50/60/80
PPS
THERMOPLASTIC
BUSHING
GASKET
VALVE BODY
NUT
THERMOPLASTIC
ELASTOMER
BACK PLATE
PPS THERMOPLASTIC
OR STAINLESS STEEL
STAINLESS STEEL BACKPLATE:
STAMP AND STAR MUST
FACE AWAY FROM FLAPPER
PPS THERMOPLASTIC BACK PLATE:
GROOVE MUST FACE TOWARDS FLAPPER.
FRONT PLATE;
STAMP AND STAR MUST FACE
AWAY FROM FLAPPER.
FIGURE 70
IMPORTANT
Special screws are used in the air flapper valve.
Replacement screws are available in kit form from
Lennox Repair Parts. Do not use Loctite or similar
thread seizing compounds to secure screws.
WARNING
When servicing the air intake flapper valve, keep
in mind that it is only moderately warm during unit
operation. After unit cycles off, residual heat in
combustion chamber will transfer back to valve
causing it to become very hot. Allow it to cool 10
to 15 minutes before handling. The blower can
also be run to cool air intake.
COVER SCREWS (8)
TORQUE TO 15 + IN. LBS.
FLAPPER FRONT
PLATE
SCREW
SPACER
TORQUE TO
9 + 1 IN LBS.

AIR FLAPPER VALVE ASSEMBLY

G21Q−100−5 to −8 & G21V−100−7, −8
PPS
THERMOPLASTIC
BUSHING
NUT
BACK
PLATE
SPACER
HOLES SHOULD LINE UP BE
TWEEN THE CENTER PLATE AND
THE FRONT PLATE
AIR FLAPPER VALVE ASSEMBLY−100
PPS
THERMOPLASTIC
BUSHING
NUT
BACK
PLATE
DIMENSION "A"
CLEARANCE
CLEARANCES ARE SUBJECT TO CHANGE.
REFER TO LENNOX REPAIR PARTS OR SER
VICE AND APPLICATION NOTES HEATING
TAB FOR LATEST INFORMATION.
Page 52
VALVE BODY
STAMPS IN SAME
THERMOPLASTIC
QUADRANT AND
ELASTOMER
FACING AWAY
FROM UNIT
GASKET
FLAPPER
FRONT
PLATE
SCREW
TORQUE TO
10 + 1 IN LBS.
FIGURE 71
VALVE BODY
STAMPS IN SAME
THERMOPLASTIC
QUADRANT AND
ELASTOMER
FACING AWAY
FROM UNIT
GASKET
CENTER
FLAPPER
CORK GASKET
QUADRANTS
SCREW
TORQUE TO
10 + 1 IN LBS.
FIGURE 72
CENTER
PLATE
COVER
SCREWS
(8)
PLATE
COVER
SCREWS
(8)