Lennox LGT Series Unit Information page 26

INSERT LOCATION
STANDARD HEAT (130,000BTUH)
INSERTS (2)
FIGURE 15
4-Burner Box Assembly (Figure 16)
The burners are controlled by the spark electrode, flame
sensing electrode, gas valve and combustion air blower.
The spark electrode, flame sensing electrode and gas
valve are directly controlled by ignition control. Ignition
control and combustion air blower is controlled by A55
Unit Controller.
BURNER BOX ASSEMBLY
Rollout Switch
Gas Valve
Burners
Gas Manifold
FIGURE 16
Burners
All units use cluster type inshot burners (see figure 17).
Burners are factory set and do not require adjustment.
A peep hole with cover is furnished in the heating ac-
cess panel for flame viewing. Always operate the unit
with the access panel in place.
Burners can be removed for service as an assembly.
Burner maintenance and service is detailed in the
SERVICE CHECKS section of this manual
TYPICAL GAS BURNER ASSEMBLY
Orifice
Each burner uses an orifice (figure 18) which is pre-
cisely matched to the burner input. Install only the ori-
fices with the same threads. The orifice is threaded into
the burner manifold. The burner is supported by the
orifice and will easily slide off for service.
NOTE-Do not use thread sealing compound on the or-
ifices. Using thread sealing compound may plug the
orifices.
Each orifice and burner are sized specifically to the
unit. Refer to ProductZone
rect sizing information.
ORIFICE WITH PIPE THREADS
Tighten to 6.25 + .5 ft.lbs.
Do not over-tighten.
5-Primary High Temperature Limits S10
S10 is the primary high temperature limit and is located on
the blower deck to the left of the blower housing.
Primary limit S10 is wired to the A55 Unit Controller which
energizes burner 1 control (A3). Its N.C. contacts open
to de-energize the ignition control when excessive tem-
perature is reached in the blower compartment. If the limit
trips the blower will be energized. Limit settings are facto-
ry set and cannot be adjusted. If limit must be replaced,
the same type and set point must be used.
Page 26
FIGURE 17
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FIGURE 18