Typical Installation - Lennox G21Q Series Installation Instructions Manual

*4 7<3,&$/ ,167$//$7,21
FLEXIBLE ISOLATION
HANGER
EXHAUST PIPE
2”(51mm) PVC
SUPPLY AIR PLENUM
1.5 TO 3 LB. (24 to 48 kg) DENSITY,
MATTE FACE, 1” (25mm) THICK
INSULATION INSULATED PAST
FIRST ELBOW
MUFFLER**
FLEXIBLE BOOT IN PLENUM
OR DUCT (SUPPLY AIR)
CONDENSATE DRIP LEG
ISOLATION PADS (ISOMODE) (4)
*Installationproceduresoutlined inthis manualarepresentedasrecommendationonly and donot supersedeor replacelocal orstate
code. If local or state codes do not exist, the procedures outlined in this manual are recommended only and do not constitute code.
**All G21-80/100 units require the use of at least one muffler in the exhaust pipe and one in the intake pipe. Mufflers are recommended
options on all other units.
NOTE- -Many of the specific installation recommendations such as insulated plenums, flexible boots and isolation hangers are strongly
suggested to control vibration and to ensure acceptable sound levels in the conditioned space. The recommendations should be used
as a guideline when installing the system. Specific installation methods, duct construction and insulation methods may vary and are
acceptable provided the methods provide the same objective, are industry accepted and meet code requirements.
INTAKE PIPE 2”
FLEXIBLE BOOT IN DUCT OR PLENUM (SUPPLY AIR)
(51mm) PVC
MUFFLER**
SUPPLY AIR
CONTROL
ACCESS PANEL
BLOWER
COMPARTMENT
ACCESS PANEL
FLEXIBLE BOOT IN PLENUM
OR DUCT (RETURN AIR)
3DJH 
RETURN
AIR
FLEXIBLE BOOT IN
DUCT OR PLENUM
(RETURN AIR)
MANUAL
MAIN SHUT OFF
VALVE
GAS SUPPLY PIPING
CENTERED IN INLET
HOLE (SLOT)
DRIP LEG
GAS
CONNECTOR
(Gas connector may be used for Ca-
nadian installation if acceptable by
local authority having jurisdiction.)
ELECTRICAL CONDUIT:
IF CLAMPED TO UNIT
IT MUST BE ISOLATED
FROM DUCT WORK AND
JOISTS
RETURN AIR PLENUM
1.5 TO 3 LB. (24 to 48kg) DENSITY,
MATTE FACE, 1” (25mm)
THICK INSULATION
INSULATED PAST FIRST ELBOW