Existing Common Vent Systems - Lennox 13CHA SERIES Installation Instructions Manual

Service Clearances
30
(762)
*Rear clearance is 18" (457) when required for
accessory maintenance.
NOTE − Top Clearance − 36 in. (914 mm)
NOTE − Entire perimeter of unit base requires
support when elevated above mounting surface.
Figure 2
NOTE − Do not permit overhanging structures or shrubs to
obstruct condenser air discharge outlet.
In the U.S. units may be installed on combustible floors
made from wood or class A, B, or C roof covering material.
In Canada, units may be installed on combustible floors.

Existing Common Vent Systems

The 13CHA packaged cooling units with auxiliary electric
heat may replace an existing furnace which is being re-
moved from a venting system commonly run with sepa-
rate gas appliances. In this case, the existing vent system
is likely to be too large to properly vent the remaining at-
tached appliances.
Conduct the following test while each appliance is operat-
ing and the other appliances (which are not operating) re-
main connected to the common venting system. If the
venting system has been installed improperly, you must
correct the system as indicated in the general venting re-
quirements section.
3 (76)*
REAR
24
(610)
FRONT
48 (1219)
1 − Seal any unused openings in the common venting sys-
tem.
2 − Inspect the venting system for proper size and horizontal
pitch. Determine that there is no blockage, restriction,
leakage, corrosion, or other deficiencies which could
cause an unsafe condition.
3 − Close all building doors and windows and all doors be-
tween the space in which the appliances remaining
connected to the common venting system are located
and other spaces of the building. Turn on clothes dry-
ers 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 oper-
ate at maximum speed. Do not operate a summer ex-
haust fan. Close fireplace 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 flue gases at the draft hood relief opening.
Use the flame of a match or candle, or smoke from a
cigarette, cigar, or pipe.
6 − After determining that each appliance connected to the
common venting system is venting properly, (step 3)
return all doors, windows, exhaust fans, fireplace
dampers, and any other gas−burning appliances to
their previous mode of operation.
7 − If a venting problem is found during any of the preced-
ing tests, the common venting system must be modi-
fied 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
ANSI-Z223.1/NFPA 54 in the USA, and the appropri-
ate Category 1 Natural Gas and Propane appliances
venting sizing tables in the current standards of the
CSA B149 Natural Gas and Propane Installation
Codes in Canada.)
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National Fuel Gas Code