Page 24
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 second
coat to end of pipe.
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 indicate an
improper assembly due to insufficient solvent.
9 - Handle joints carefully until completely set.
Venting Practices
FIGURE 23
* See table 11 for allowable pipe.
Piping Suspension Guidelines
NOTE
- Isolate piping at the point where it exits the outside wall or
roof in order to prevent transmission of vibration to the structure.
SCHEDULE 40
PVC - 5'
all other pipe* - 3'
Wall
inside
outside
24” maximum
3/4” minimum
Wall Thickness Guidelines
insulation
(if required)
2. 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.
3. 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.
CHIMNEY
OR GAS
VENT
(Check sizing
for water
heater only)
FURNACE
(Replaced
by ML195)
WATER
HEATER
OPENINGS
(To Adjacent
Room)
If an ML195UH furnace replaces a furnace which
was commonly vented with another gas appliance,
the size of the existing vent pipe for that gas ap
pliance 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.
FIGURE 24
REPLACING FURNACE THAT
WAS PART OF A COMMON
VENT SYSTEM
Exhaust Piping (Figures 27 and 28)
Route piping to outside of structure. Continue with installa
tion following instructions given in piping termination sec
tion.
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.
