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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 burner have 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 stan-
dards of the National Fuel Gas Code ANSI Z223.1.
Gas Piping
Gas supply piping should not allow more than 0.5”W.C. 
drop in pressure between gas meter and unit. Supply gas 
pipe must not be smaller than unit gas connection.
 CAUTION
If a exible gas connector is required or allowed by the 
authority that has jurisdiction, black iron pipe shall be 
installed at the gas valve and extend outside the furnace 
cabinet.  The  exible  connector  can  then  be  added 
between the black iron pipe and the gas supply line.
Gas Supply
 WARNING
Do not over torque (800 in-lbs) or under torque (350 in-
lbs) when attaching the gas piping to the gas valve.
1 -   This unit is shipped standard for left or right side 
installation of gas piping (or top entry in horizontal 
applications). Connect the gas supply piping into the 
gas valve. The maximum torque is 800 in lbs and 
minimum torque is 350 in lbs when when attaching 
the gas piping to the gas valve.
2 -  When connecting the gas supply piping, consider 
factors such as length of run, number of ttings, and 
furnace rating to avoid excessive pressure drop. 
TABLE  6  lists  recommended  pipe  sizes  for  typical 
applications.
3 -  The gas piping must not run in or through air ducts, 
clothes chutes, gas vents or chimneys, dumb waiters, 
or elevator shafts.
4 -  The piping should be sloped 1/4 inch (6.4 mm) per 
15 feet (4.57 m) upward toward the meter from the 
furnace. The piping must be supported at proper 
intervals  [every  8  to  10  feet  (2.44  to  3.01  m)]  with 
suitable hangers or straps. Install a drip leg in vertical 
pipe runs to the unit.
5 -  A 1/8” N.P.T. plugged tap or pressure post is located 
on the gas valve to facilitate test gauge connection. 
See FIGURE 25.
6 -  In some localities, codes may require the installation 
of a manual main shut-o valve and union (furnished 
by the installer) external to the unit. The union must 
be of the ground joint type.
 IMPORTANT
Compounds used on threaded joints of gas piping must 
be resistant to the actions of liquied petroleum gases.
NOTE - If  emergency  shuto  is  necessary,  shut  o  the 
main manual gas valve and disconnect main power to the 
furnace. The installer should properly label these devices.