507581-04 Page 17  of  60Issue 2128
CARBON MONOXIDE POISONING HAZARD
Failure  to  follow  the  steps  outlined  below  for  each 
appliance  connected  to  the  venting  system  being 
placed into operation  could result in carbon monoxide 
poisoning or death. 
   WARNING
The  following  steps  shall  be  followed  for  each  appliance 
connected  to  the  venting  system  being  placed  into 
operation,  while  all  other  appliances  connected  to  the 
venting system are not in operation: 
1.  Seal  any  unused  openings  in  the  common  venting 
system.
2.  Inspect  the  venting  system  for  proper  size  and 
horizontal pitch. Determine that there is no blockage, 
restriction,  leakage,  corrosion,  or  other  deciencies 
which could cause an unsafe condition. 
3.  Close  all  building  doors  and  windows  and  all  doors 
between the space in which the appliances 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 replace dampers. 
4.  Follow the lighting instructions. Turn on the appliance 
that is being inspected. Adjust the thermostat so that 
the appliance operates continuously. 
5.  After the main burner has operated for 5 minutes, test 
for leaks of ue gases at the draft hood relief opening. 
Use the ame of a match or candle. 
6.  After  determining  that  each  appliance  connected  to 
the common venting system is venting properly, (step 
3)  return  all  doors,  widows,  exhaust  fans,  replace 
dampers,  and  any  other  gas  burning  appliances  to 
their previous mode of operation.
7.  If  a  venting  problem  is  found  during  any  of  the 
preceding tests, the common venting system must be 
modied to correct the problem. 
Resize the common venting system to the minimum vent 
pipe  size  determined  by  using  the  appropriate  tables  in 
Appendix  G.  (These  are  in  the  current  standards  of  the 
National Fuel Gas Code ANSI Z223.1.) 
Figure 22. 
If this gas 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 ue 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.
Exhaust Piping
Route  piping  to  outside  of  structure.  Continue  with 
installation following instructions given in piping termination 
section.
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  even 
with the top or outlet end of the metal stack. 
   CAUTION
The exhaust vent pipe operates under positive pressure 
and  must  be  completely  sealed  to  prevent  leakage  of 
combustion products into the living space.
   CAUTION
Vent Piping Guidelines
This gas furnace can be installed as either Non-Direct Vent 
or a Direct Vent gas central furnace.
NOTE: In Non-Direct Vent installations, combustion air is 
taken from indoors and ue gases are discharged outdoors.
Intake  and  exhaust  pipe  sizing  -  Size  pipe  according  to 
Table  4 and Table 5A through Table 5C. Table 4 lists the 
minimum  vent  pipe  lengths  permitted.  Table  5A  through 
Table 5C list the maximum pipe lengths permitted.