Run Pitch = 1/4"
Per Ft. Min.
1. Flue pipe screen
(inside flue pipe)
2. Flue pipe
Height to provide
12" clearance to
max. snow level.
3" MIN. - 48" MAX.
3. Air intake pipe
Existing Venting Systems
When an existing furnace is removed or replaced, the original
venting system may no longer be sized to properly vent the
attached appliances. An improperly sized venting system can
result in spillage of flue products into the living space, the
formation of condensate, leakage, etc. See "Adjust Blower
Speed" section for the "Carbon Monoxide Poisoning Hazard" for
proper test procedure.
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.
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 venting system.
2. Inspect the venting system for proper size and horizontal
pitch, as required in the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 or the CSA B149.1, Natural Gas and
Propane Installation Codes and these instructions.
Determine that there is no blockage or restriction, leakage,
corrosion and other deficiencies which could cause an
3. As far as practical, close all building doors and windows
and all doors between the space in which the appliance(s)
connected to the venting system are located and other
spaces of the building.
4. Close fireplace dampers.
5. Turn on clothes dryers and any appliance not connected to
the venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they are operating
at maximum speed. Do not operate a summer exhaust fan.
6. Follow the lighting instructions. Place the appliance being
inspected into operation. Adjust the thermostat so
appliance is operating continuously.
7. Test for spillage from draft hood equipped appliances at the
draft hood relief opening after 5 minutes of main burner
operation. Use the flame of a match or candle.
8. If improper venting is observed during any of the above
tests, the venting system must be corrected in accordance
with the National Fuel Gas Code, ANSI Z223.1/NFPA 54
and/or CSA B149.1, Natural Gas and Propane Installation
9. After it has been determined that each appliance connected
to the venting system properly vents when tested as
outlined above, return doors, windows, exhaust fans,
fireplace dampers and any other gas-fired burning
appliance to their previous conditions of use.