Heating - Lennox G32V Series Service Literature

D−Heating Components
1.Flame Sensor
A flame sensor is located on the left side of the burner sup-
port. See figure 23. The sensor is mounted on a bracket in
the burner support and the tip protrudes into the flame en-
velope of the left−most burner. The sensor is fastened to
burner supports and can be removed for service without re-
moving any part of the burners. During operation, flame is
sensed by current passed through the flame and sensing
electrode. The SureLight control allows the gas valve to re-
main open as long as flame signal is sensed.
SENSOR
3/8"
FIGURE 23
NOTE − The G32V furnace contains electronic compo-
nents that are polarity sensitive. Make sure that the fur-
nace is wired correctly and is properly grounded.
2.Combustion Air Inducer (B6)
All G32V units use a two−stage combustion air inducer to move
air through the burners and heat exchanger during heating op-
eration. The blower uses a 120VAC motor. The motor operates
during all heating operation and is controlled by the SureLight
integrated control A92 and the two−stage control board A86.
The combustion air inducer operates for 15 seconds before
burner ignition (pre-purge) and for 5 seconds after the gas
valve closes (post-purge). The combustion air inducer oper-
ates on low speed during first−stage heat (low fire), then
switches to high speed for second−stage heat (high fire).
3.Primary Limit Control (S10) Figure 24
The primary limit (S10) on G32V units is located in the
middle of the heating vestibule panel. When excess heat is
sensed in the heat exchanger, the limit will open. If the limit
is tripped, the furnace control energizes the supply air blow-
er and de−energizes the gas valve. The limit automatically
resets when unit temperature returns to normal. The switch
is factory set and cannot be adjusted. The switch may
have a different setpoint for each unit model number.
However, the setpoint will be printed on the outside face
of the limit.
IGNITOR
LIMIT CONTROL (S10) FOR
G32V SERIES UNITS AND ALTERNATE STYLE
Units may be equipped with either style limit.
INSULATING COVER (s)
4.Flame Rollout Switch (S47)
Flame rollout switch S47 is a SPST N.C. high temperature limit
located on the right side of the burner box assembly (see figure
25). S47 is wired to the burner ignition control A92. When
S47 senses flame rollout (indicating a blockage in the
combustion passages), the flame rollout switch trips,
and the ignition control immediately closes the gas
valve. Switch S47 in all G32V units is factory preset to open
at 200_F + 12_F (93_C + 6.7_C) on a temperature rise. All
flame rollout switches are manually reset.
FLAME ROLLOUT SWITCH (S47)
5.Burners
All units use inshot burners (see figure 26). Burners are factory
set and do not require adjustment. A sight glass is furnished
in the burner box assembly for flame viewing. Always op-
erate the unit with the burner box cover in place. Burners
can be removed as an assembly for service. Burner mainte-
nance and service is detailed in the MAINTENANCE section
of this manual. Each burner uses an orifice which is precisely
matched to the burner input (see nameplate for orifice size).
The orifice is threaded into the burner manifold. The burner
is supported by the orifice and will easily slide off for service.
Each orifice and burner are sized specifically to the unit. Re-
fer to Lennox Repair Parts Listing for correct sizing informa-
tion. A flame retention ring in the end of each burner maintains
correct flame length and shape and keeps the flame from lifting
off the burner head. In addition, the burner entrance to each
clamshell (Figure 2) is fitted with a corbel cup (orifice) used to
direct the flow of com-
bustion products.
Page 34
FIGURE 24
FLAME ROLLOUT
SWITCH (S47)
FIGURE 25
TYPICAL BURNER ASSEMBLY
FIGURE 26