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Testing for Proper Venting and Sufficient Combustion Air for Non-Direct Vent Applicaitons
WARNING
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 monox
ide poisoning or death.
The following steps shall be followed for each ap
pliance connected to the venting system being
placed into operation, while all other appliances con
nected to the venting system are not in operation.
After the 95AF2DFV gas furnace has been started, the fol
lowing test should be conducted to ensure proper venting
and sufficient combustion air has been provided to the
95AF2DFV as well as to other gas‐fired appliances which
are separately vented.
If a 95AF2DFV furnace replaces a Category I 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 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.
The test should be conducted while all appliances (both in
operation and those not in operation) are connected to the
venting system being tested. If the venting system has
been installed improperly, or if provisions have not been
made for sufficient amounts of combustion air, corrections
must be made as outlined in the previous section.
1 - Seal any unused openings in the venting system.
2 - Visually inspect the venting system for proper size and
horizontal pitch. Determine there is no blockage or re
striction, leakage, corrosion, or other deficiencies
which could cause an unsafe condition.
3 - To the extent that it is practical, close all building doors
and windows and all doors between the space in
which the appliances connected to the venting system
are located and other spaces of the building.
4 - Close fireplace dampers.
5 - Turn on clothes dryers and any appliances not con
nected to the 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.
6 - Follow the lighting instruction to place the appliance
being inspected into operation. Adjust thermostat so
appliance will operate continuously.
7 - Use the flame of match or candle to test for spillage of
flue gases at the draft hood relief opening after 5 min
utes of main burner operation.
8 - If improper venting is observed during any of the
above tests, the venting system must be corrected or
sufficient combustion/make‐up air must be provided.
The venting system should be re‐sized to approach
the minimum size as determined by using the ap
propriate tables in appendix G in the current standards
of the National Fuel Gas Code ANSI-Z223.1/NPFA 54
in the U.S.A., and the appropriate Natural Gas and
Propane appliances venting sizing tables in the cur
rent standard of the CSA-B149 Natural Gas and Pro
pane Installation Codes in Canada.
9 - After determining that each appliance remaining con
nected to the common venting system properly vents
when tested as indicated in step 3, return doors, win
dows, exhaust fans, fireplace dampers and any other
gas‐burning appliance to their previous condition of
use.
