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Common Venting Using Tile−Lined Masonry Chimney
TILE−LINED
MASONRY
CHIMNEY
PERMANENTLY
SEALED FIREPLACE
OPENING
FURNACE
OTHER
APPLIANCE
FIGURE 6
B VENT
VENT
ADAPTER
ASSEMBLY
1 FOOT
MINIMUM
(2 ft.
preferred)
8 − When an exterior masonry chimney is being used,
the furnace must be commonly vented with at least
one other drafthood−equipped gas−fired appliance.
9 − Continue with furnace installation, start−up and
adjustments as outlined in furnace installation
instructions.
NOTE − Furnace blower heating speed should be
adjusted so that temperature rise is at the high
end of the range listed on the unit rating plate.
10 − Test the operation of the blocked vent switch.
CAUTION − Ensure good ventilation of the area
where the furnace is installed before performing
this test.
a − Remove double−walled B−vent from top of vent
adapter assembly.
b − Adjust room thermostat to signal heating
demand.
c − Allow furnace to operate for 2 minutes, then
completely cover the top of the vent adapter
assembly outlet to simulate a vent blockage.
Furnace should shut off within 2 minutes.
d − Remove blockage and
allow unit to cool for 5
minutes
. Press reset button on blocked vent
switch. Reinstall double−walled vent pipe. Adjust
thermostat to normal setting.
11 − Test the furnace for proper draft and spillage.
a − 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.
b − 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 fireplace dampers.
c − Follow the lighting instructions. Turn on the
appliance that is being inspected. Adjust the
thermostat so that the appliance operates
continuously.
d − After the main burner has operated for 5
minutes, test for leaks of flue gases at the draft
hood or vent adapter relief opening. Use the
flame of a match or candle, or smoke from a
cigarette, cigar, or pipe.
e
− 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.
f − If a venting problem is found during any of the
preceding tests, the common venting system
must be modified to correct the problem.
