Lennox LGH094U Unit Information page 46

TABLE 4
GAS VALVE REGULATION FOR LGH UNITS
Operating Pressure
Maximum (outlet) Factory Setting
Inlet
Natural
Pressure
Low
13.0"W.C. 1.6+0.2"W.C. 3.7+0.3"W.C.
3232Pa 398+50Pa 920+75Pa
WHITE-RODGERS 36C76 GAS VALVE
STAGE 2 MANUAL MANIFOLD
INLET
PRESSURE ADJUSTMENT
PRESSURE
SCREW UNDER CAP
TAP (SIDE)
GAS VALVE
SHOWN IN "OFF"
POSITION
HONEYWELL VR8305/VR8205 GAS VALVE
HIGH FIRE
LOW FIRE
ADJUSTMENT
ADJUSTMENT
INLET
PRESSURE
TAP
FIGURE 31
11-Spark Electrodes
An electrode assembly is used for ignition spark. Two iden­
tical electrodes are used (one for each gas heat section).
The electrode is mounted through holes on the left‐most
end of the burner support. The electrode tip protrudes into
the flame envelope of the adjacent burner. The electrode
assembly is fastened to burner supports and can be re­
moved for service without removing any part of the burners.
During ignition, spark travels through the spark electrode
(figure 32) and ignites the left burner. Flame travels from
burner to burner until all are lit.
L.P
.
High Low High
5.5+0.3"W.C. 10.5+0.5"W.C.
1368+75Pa 2611+7124Pa
MANIFOLD
PRESSURE
TAP (SIDE)
D-1
C-1
GV-1
C2
GV-2
GAS VALVE SHOWN
IN "OFF" POSITION
MANIFOLD
PRESSURE
TAP
The spark electrode is connected to the ignition control by a
8 mm silicone‐insulated stranded high voltage wire. The
wire uses 1/4" (6.35 mm)female quick connect on the elec­
trode end and female spark plug-type terminal on the igni­
tion control end.
NOTE-IN ORDER TO MAXIMIZE SPARK ENERGY TO
ELECTRODE, HIGH VOLTAGE WIRE SHOULD TOUCH
UNIT CABINET AS LITTLE AS POSSIBLE.
.125" ± .015"
(3.2 mm ± .4 mm)
GROUND
ELECTRODE
12-Flame Sensors
A flame sensor is located on the right side of each burner
support. The sensor is mounted through a hole in the burn­
er support and the tip protrudes into the flame envelope of the
right most burner. The sensor assembly is fastened to burner
supports and can be removed for service without removing any
part of the burners.
When flame is sensed by the flame sensor (indicated by
microamp signal through the flame) sparking stops imme­
diately. During operation, flame is sensed by current
passed along the ground electrode (located on the spark
electrode), through the flame and into the sensing elec­
trode. The ignition control allows the gas valve to stay
open as long as a flame signal (current passed through the
flame) is sensed.
Page 46
ELECTRODE
GROUND
FIGURE 32
SENSOR
FIGURE 33