Page 44
3-Burner Assembly (Figure 20)
sensing electrode, gas valve and combustion air blower.
valve are directly controlled by ignition control. Ignition
control and combustion air blower is controlled by Unit
Controller A55.
Burners
-
ers are factory set and do not require adjustment. A peep
hole with cover is furnished in the heating access panel
panel in place. Burners can be removed individually for
service. Burner maintenance and service is detailed in the
SERVICE CHECKS section of this manual
TYPICAL GAS BURNER ASSEMBLY
BURNERS
ORIFICE
SENSOR
BURNER
SUPPORT
BURNER
SUPPORT CAP
FIGURE 20
ORIFICE WITH
PIPE THREADS
Tighten to 6.25 + .5 ft.lbs.
Do not over-tighten.
Tighten to 14 + .5 ft/lbs
Do not over-tighten.
ORIFICE WITH
STRAIGHT THREADS
FIGURE 21
Orice
is precisely matched to the burner input. Install only the
NOTE-Do not use thread sealing compound on the oric-
es. Using thread sealing compound may plug the orices.
Refer to Lennox Repair Parts Listing for correct sizing
information.4-Primary High Temperature Limits S10 &
S99
S10 is the primary high temperature limit for gas heat sec-
gas heat section two.
shield behind the blower housing. In this location S10 and
Primary limit S10 is wired to the Unit Controller A55 which
wired to the A55 Unit Controller which energizes burner 2
control (A12). Its N.C. contacts open to de-energize the
ignition control when excessive temperature is reached in
the blower compartment. At the same time, the N.O. con-
K3 through control A55. If either limit trips the blower will
be energized.
Limits settings are factory set and cannot be adjusted. If
limit must be replaced same type and set point must be
used. See Lennox Repair Parts Handbook.
CONDENSER
DIVIDER
PANEL
S10 AND S99 ON
HIND BLOWER
HOUSING
GAS HEAT
GAS HEAT
SECTION 2
FIGURE 22
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