Page 19
Intake Piping
1 − Cement intake piping in slip connector located at top of
unit.
2 − Route piping to outside of structure. Continue with
installation following instructions given in exhaust and
intake piping termination section.
Exhaust Piping
1 − Cement exhaust piping into flue collar socket located
on the left side of the top cap.
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 ft. (1.52m) using hangers for schedule 40 pipe. All
other pipe must be supported every 3 ft. (.91m).
NOTE − Exhaust piping should be checked carefully to
make sure there are no sags or low spots.
NOTE − Exhaust piping must be insulated with 1/2"
(13mm) Armaflex or equivalent when run through un
heated space. Do not leave any area of exhaust pipe
open to outside air; exterior exhaust must be insulated
with 1/2" (13mm) Armaflex or equivalent.
CAUTION
Do not discharge exhaust into an existing stack
or stack that also serves another gas appliance.
If vertical discharge through an existing unused
stack is required, insert PVC pipe inside the stack
until the end is beyond the top or outlet end of the
metal stack.
CAUTION
The exhaust vent pipe operates under positive
pressure and must be completely sealed to pre
vent leakage of combustion products into the liv
ing space.
Removal of Unit from Common Venting System
In the event that an existing furnace is removed from a
venting system commonly run with separate gas ap
pliances, the venting system may be too large to properly
vent the remaining attached appliances. The following test
should be conducted while all appliances (both in operation
and those not in operation) are connected to the common
venting system. If the venting system has been installed
improperly, corrections must be made as outlined in the
previous section.
1 − Seal any unused openings in the common venting sys
tem.
2 − Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion and other deficiencies
which could cause an unsafe condition.
3 − Insofar as is practical, close all building doors and win
dows and all doors between the space in which the ap
pliances remaining connected to the common venting
system are located and other spaces of the building. Turn
on clothes dryers and any appliances not connected to
the common venting system. Turn on any exhaust fans,
such as range hoods and bathroom exhausts, so they will
operate at maximum speed. Do not operate a summer
exhaust fan. Close fireplace dampers.
4 − Follow the lighting instruction. Place the appliance be
ing inspected in operation. Adjust thermostat so ap
pliance will operate continuously.
5 − Test for spillage at the draft hood relief opening after 5
minutes of main burner operation. Use a draft gauge or
the flame of match or candle, or smoke from a cigarette,
cigar.
6 − After it has been determined that each appliance re
maining connected to the common venting system
properly vents when tested as outlined above, return
doors, windows, exhaust fans, fireplace dampers and
any other gasburning appliance to their previous con
dition of use.
7 − If improper venting is observed during any of the
above tests, the common venting system must be cor
rected. The common venting system should be re−
sized to approach the minimum size as determined by
using the appropriate tables in appendix G in the cur
rent standards of the National Fuel Gas Code ANSI
Z223−1 in the U.S.A., and the appropriate Category 1
Natural Gas and Propane appliances venting sizing
tables in the current standards of the CAN/
CGA−B149.1 and .2 in the Natural Gas and Propane
Installation Code in Canada.
Intake and Exhaust Piping Terminations
Intake and exhaust pipes may be routed either horizontally
through an outside wall or vertically through the roof. In attic
or closet installations, vertical termination through the roof
is preferred. Figures 21 through 33 show typical termina
tions.
1 − Use recommended piping materials for both intake
and exhaust piping.
2 − Secure all joints, including drain leg, gas tight using
approved primer and cement.
3 − Piping diameters should be determined according to
length of pipe run. See vent pipe specifications on
page 6. Locate intake piping upwind (prevailing wind)
from exhaust piping. To avoid re−circulation of exhaust
gas on roof terminations, end of exhaust pipe must be
higher than intake pipe.