Testing For Combustion Air Non-Direct Vents - Lennox ML193UH030XE36B Installation Instructions Manual

Testing for Proper Venting and Sufficient Combustion Air for Non-Direct Vent Applications
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 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.
After the ML193UHE gas furnace has been started, the
following test should be conducted to ensure proper vent-
ing and sufficient combustion air has been provided to the
ML193UHE as well as to other gas-fired appliances which
are separately vented.
If a ML193UHE 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 ap-
pliance.
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
restriction, 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
connected 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
minutes 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 appropriate 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 current standard of the
CSA-B149 Natural Gas and Propane Installation
Codes in Canada.
9 - After determining that each appliance remaining
connected to the common venting system properly
vents when tested as indicated in step 3, return
doors, windows, exhaust fans, fireplace dampers
and any other gas-burning appliance to their previous
condition of use.
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