Lennox LGH074 User Manual

Page 7
507246-02 6/2019
to the unit and use the inspection port in the access
panel to check the ame.
BURNER BOX ASSEMBLY
036-074 UNITS - ONE- & TWO-STAGE
GAS
VALVE
GAS
MANIFOLD
FLAME
SENSOR
BURNERS
NOX INSERT
FIGURE 9
BURNER BOX ASSEMBLY
036-074U UNITS - FOUR-STAGE
GV1
GAS VALVE
GV3
GAS VALVE
GAS
MANIFOLD
BURNERS
FIGURE 10
BURNER BOX ASSEMBLY - 092-360 UNITS
GAS
MANIFOLD
GAS
VALVE
BURNERS
FIGURE 11
TABLE 1
UNIT FILTERS
Unit Qty Filter Size - inches (mm)
036, 048 4 16 X 20 X 2 (406 X 508 X 51)
060, 072, 074 4 20 X 20 X 2 (508 X 508 X 51)
092, 094, 102, 120,
122, 150, 152
4 20 X 25 X 2 (508 X 635 X 51)
156 - 300S/U 6 24 X 24 X 2 (610 X 610 X 51)
242, 300H, 360 12 20 X 20 X 2 (508 X 508 X 51)
NOTE - Filters must be ULC approved or equivalent for use in Canada.
Lubrication
All motors are lubricated at the factory. No further
lubrication is required.
156-360 Units -
Blower shaft bearings are prelubricated. For extended
bearing life, relubricate at least once every two years
with a lithium base grease, such as Alvania 3 (Shell Oil),
Chevron BRB2 (Standard Oil) or Regal AFB2 (Texas Oil).
Use a hand grease gun for relubrication. Add only enough
grease to purge through the bearings so that a bead of
grease appears at the seal lip contacts.
Manifold Pressures
Manifold pressures are shown in table 2. Refer to Figure 1,
Figure 2, or Figure 3, or Figure 4 to locate pressure ports.
TABLE 2
MANIFOLD PRESSURES in w.g.
Unit
Natural Gas Propane (LP) Gas
1st
Stage
± 0.2
2nd
Stage
± 0.3
1st
Stage
± 0.2
2nd
Stage
± 0.3
036, 048, 060, 072,
074 Std./High Heat
NA
3.5
(0.87)
NA
10.5
(2.61)
036, 048, 060, 072,
074 Dual Heat
2.0
(0.47)
3.5
(0.87)
5.9
(1.47)
10.5
(2.61)
092-360
1.6
(0.40)
3.7
(0.92)
5.5
(1.47)
10.5
(2.61)
Burners
Clean the burners as follows:
1 - Turn off the electrical power and the gas supply to
the unit.
2 - Remove the burner compartment access panel.
3 - Remove top burner box panel. See Figure 9, Figure
10, or “Figure 10” on page 7
4 - Remove screws securing burners to burner
support and lift the entire burner assembly from the
orices. Clean as necessary. Spark gap on ignition
electrode must be properly set. Refer to the Heating
Adjustment section in the installation instructions.
5 - Replace burners and screws securing burner.
Replace the top burner box panel.
6 - Turn on the electrical power and the gas supply to
the unit. Follow the operating instructions attached

Lennox LGH074 Specifications

General

Brand	Lennox
Model	LGH074
Category	Accessories
Language	English