Venting Practices - Lennox G61MPV?36B?045 Installation Instructions Manual

5 − Uniformly apply a liberal coat of PVC primer for PVC or
use a clean dry cloth for ABS to clean inside socket
surface of fitting and male end of pipe to depth of fitting
socket.
NOTE − Furnace flue collar and air inlet fitting are both
made of ABS material. Usetransition solvent cement
when bonding ABS to either PVC or CPVC, refer to the
procedure specified in ASTM D3138..
6 − Promptly apply solvent cement to end of pipe and in-
side socket surface of fitting. Cement should be ap-
plied lightly but uniformly to inside of socket. Take
care to keep excess cement out of socket. Apply sec-
ond coat to end of pipe.
NOTE − Time is critical at this stage. Do not allow prim-
er to dry before applying cement.
7 − Immediately after applying last coat of cement to pipe,
and while both inside socket surface and end of pipe
are wet with cement, forcefully insert end of pipe into
socket until it bottoms out. Turn PVC pipe 1/4 turn dur-
ing assembly (but not after pipe is fully inserted) to dis-
tribute cement evenly. DO NOT turn ABS or cellular
core pipe.
NOTE − Assembly should be completed within 20 sec-
onds after last application of cement. Hammer blows
should not be used when inserting pipe.
8 − After assembly, wipe excess cement from pipe at end
of fitting socket. A properly made joint will show a
bead around its entire perimeter. Any gaps may indi-
cate a defective assembly due to insufficient solvent.
9 − Handle joints carefully until completely set.

Venting Practices

The thickness of construction through which vent pipes
may be installed is 24" (610mm) maximum and 3/4"
(19mm) minimum. If a G61MPV furnace replaces a furnace
which was commonly vented with another gas appliance,
the size of the existing vent pipe for that gas appliance must
be checked. Without the heat of the original furnace flue
products, the existing vent pipe is probably oversized for
the single water heater or other appliance. The vent should
be checked for proper draw with the remaining appliance.
1 − Use recommended piping materials for exhaust pip-
ing.
2 − Secure all joints so that they are gas-tight using ap-
proved cement.
Suspend piping using hangers at a minimum of every 5
feet (1.52m) for schedule
40 PVC and every 3 feet
(.91m) for ABS−DWV, PVC−
DWV, SPR−21 PVC, and
SDR−26 PVC piping. A suit-
able hanger can be fabri-
cated by using metal or
plastic strapping or a large
wire tie.
3 − In areas where piping penetrates joists or interior
walls, hole must be large enough to allow clearance on
all sides of pipe through center of hole using a hanger.
Exhaust Piping (Figures 23 and 24)
NOTE − A 2" diameter PVC street ell is located on the
blower deck of 60C−110 and 60C−111 units. In upflow or
downflow applications the street ell must be glued us-
ing transition solvent cement directly into the unit flue col-
lar. See figure 23. A 3" to 2" PVC reducing ell is located on
the blower deck of the 60D−135 units. In upflow or
downflow applications, the reducing ell must be glued
using transition solvent cement directly into the unit flue
collar.
STRAPPING
(metal, plastic
or large wire
ties)
FIGURE 22
Page 21
4 − Isolate piping at the point where it exits the outside wall
or roof in order to prevent transmission of vibration to
the structure.
5 − When furnace is installed in a residence where unit is
shut down for an extended period of time, such as a
vacation home, make provisions for draining conden-
sate collection trap and lines.
1 − Choose the appropriate side for venting in upflow or
downflow positions. Exhaust piping exits from the top
of the unit in horizontal air discharge applications.
Glue the field−provided exhaust vent pipe (or provided
street ell or reducing ell in upflow or downflow applica-
tions) to the flue collar. All PVC cement joints should
be made according to the specifications outlined in
ASTM D 2855. Refer to pipe and fittings specifications
and gluing procedures.
IMPORTANT
Exhaust piping and condensate trap must be
installed on the same side of the unit in upflow and
dowflow applications or use alternate drain kit
76M20.
2 − All horizontal runs of exhaust pipe must slope back to-
ward unit. A minimum of 1/4" (6mm) drop for each 12"
(305mm) of horizontal run is mandatory for drainage.
Horizontal runs of exhaust piping must be supported ev-
ery 5 feet (1.52m) using hangers.
NOTE − Exhaust piping should be checked carefully to
make sure there are no sags or low spots.
3 − On the opposite side of the cabinet, glue the provided
2" ABS vent plug into the unused ABS flue collar with
ABS or all purpose solvent cement.
4 − Route piping to outside of structure. Continue with
installation following instructions given in piping ter-
mination section.
CAUTION
Do not discharge exhaust into an existing stack or
stack that also serves another gas appliance. If verti-
cal discharge through an existing unused stack is re-
quired, insert PVC pipe inside the stack until the end
is even with the top or outlet end of the metal stack.
CAUTION
The exhaust vent pipe operates under positive pres-
sure and must be completely sealed to prevent leak-
age of combustion products into the living space.