Lennox KGC Series Unit Information page 24

8-Gas Valves GV1
Gas valve GV1 is a two-stage redundant valve. Units are-
equipped with valves manufactured by White-Rodgers
orHoneywell. On a call for first-stage heat (low fire), the
valve is energized by the ignition control simultaneously
with the spark electrode. On a call for second-stage heat
(high fire), the second- stage operator is energized direct-
ly from A3. A manual shut-off knob is provided on the valve
for shutoff. The manual shut-off knob immediately closes
both stages without delay. On both valves, the first stage
(low fire) is quick-opening (on and off in less than 3 sec-
onds).
On the White-Rodgers valve, the second stage is
slow-opening (on to high fire pressure in 40 seconds and
off to low fire pressure in 30 seconds). The White-Rod-
gers valve is adjustable for high fire only. Low fire is not
adjustable. On the Honeywell valve, the second stage is
quick-opening.
TABLE 4
GAS VALVE REGULATION FOR KGC UNITS
Operating Pressure (outlet)
Max Inlet
Pressure Natural
Low
13.0"W.C. 1.6+0.2 3.7+0.3
9-Spark Electrodes
An electrode assembly is used for ignition spark. The elec-
trode is inserted through holes under the left-most burner.
The electrode tip protrudes into the flame envelope of the
adjacent burner. The electrode assembly is fastened to
burner supports and can be removed for service without
removing any part of the burners.
During ignition, spark travels through the spark electrode
(FIGURE 14) and ignites the left burner. Flame travels
from burner to burner until all are lit.
The spark electrode is connected to the ignition control by
an 8 mm silicone-insulated, stranded, high-voltage wire.
The wire uses a 1/4" (6.35 mm) female quick connect on
both ends of the wire.
NOTE - If the electrode wire is replaced, wire and sup-
pression must be same type of cable. See repair parts
listing for correct replacement.
The spark electrode assembly can be removed for inspec-
tion by removing the screw securing the electrode assem-
bly and sliding it out of unit.
For proper unit operation, electrodes must be positioned
and gapped correctly. Spark gap may be checked with
appropriately sized twist drills or feeler gauges. Discon-
nect power to the unit and remove electrode assembly.
The gap should be between 0.125" + 0.015" (3.2 mm + .4
mm). See FIGURE 14.
Factory Setting ( "WC)
L.P
High Low High
5.5+0.3 10.5+0.5
NOTE - IN ORDER TO MAXIMIZE SPARK ENERGY
TO ELECTRODE, HIGH-VOLTAGE WIRE SHOULD
TOUCH UNIT CABINET AS LITTLE AS POSSIBLE.
In order to maximize spark energy to electrode, high
voltage wire should touch unit cabinet as little as
possible
.
10-Flame Sensor FIGURE 15
A flame sensor is located under the left most side burn-
er. The sensor is mounted through a hole in the burner
support and the tip protrudes into the flame envelope of
the left 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 or after the eight second trial for ignition. During
operation, flame is sensed by current passed along the
ground electrode (located on the spark electrode), through
the flame and into the sensing electrode. The ignition con-
trol allows the gas valve to stay open as long as a flame
signal (current passed through the flame) is sensed.
SIDE VIEW SENSOR
Gas Flow
Page 24
IMPORTANT
IGNITOR
SPARK GAP
SHOULD BE 1/8"
(3mm)
FIGURE 14
3/8"
(10mm)
FIGURE 15
1-3/4"
(45mm)