Specifications

Page 20
stages without delay. Figure 20 shows Honeywell gas valve
components and figure 21 shows White-Rodgers gas valve
components. Table 5 shows factory gas valve regulation for
GCS24 series units.
FIGURE 20
HONEYWELL GAS VALVE GV1
PRESSURE
REGULATOR*
(under cap)
OUTLET
PRESSURE TAP
W1
TERMINAL
W1 COM.
TERMINAL
ON/OFF
KNOB
OUTLET
GROUND
TERMINAL
W2 COM.
TERMINAL
W2
TERMINAL
*Adjusts High Fire (2nd
Stage) Manifold Pressure
FIGURE 21
WHITE-RODGERS GAS VALVE GV1
W2
TERMINAL
COMMON
TERMINALS
ON/OFF
KNOB
INLET
W1
TERMINAL
OUTLET
OUTLET
PRESSURE
TAP
VENT
NOTE - VALVE IS
NOT EQUIPPED
WITH ADJUSTABLE
REGULATOR
TABLE 5
GAS VALVE REGULATION
Unit Input
K Btuh
Maximum
Inlet Pressure
in. W.C.
Operating Pressure
(outlet) in. W.C. Factory Setting
All Units
13.0
Natural* L.P.**
3.7+0.2
Low High Low High
1.6+0.1 10.5+0.55.5+0.3
* Adjustable Range 3.0 to 5.0 in. W.C. Honeywell Gas Valve only.
White-Rodgers gas valve is not adjustable.
** Field Installed Kit Adjustable Range 8.0 to 12.0 in. W.C.Honeywell
Gas Valve only. White-Rodgers gas valve is not adjustable.
K-Electrode Assembly
An electrode assembly is used for both ignition spark and
flame sensing. Two identical electrodes are used. Each elec
trode is mounted at extreme ends of the burner support. The
electrodes are mounted through holes in the burner support
and the electrode tips protrude into the flame envelope of the
adjacent burner. The electrode on the left acts as the flame
ignitor and the electrode on the right acts as the flame sensor.
The electrode assembly is fastened to burner supports and
can be removed for service without removing any part of the
burners.
SPARK ELECTRODE and FLAME SENSOR ASSEMBLY
FIGURE 22
ELECTRODE/SENSOR
GROUND
BURNER BURNER
HEAT EXCHANGER
ENTRANCE
ELECTRODE/SENSOR
During ignition, spark travels through the spark electrode (left)
and ignites the left burner. Flame travels from burner to burn
er until all are lit. When flame is sensed by the right electrode
(rightmost burner lit - indicated by microamp signal through
the flame) sparking stops. During operation, flame is sensed
by current passed along the ground electrode, through the
flame and into the sensing electrode. The ignition control al
lows the gas valve to stay open as long as a flame signal (cur
rent passed through the flame) is sensed.
1-Spark Electrode
The spark electrode is connected to the ignition control by
a 5mm silicone insulated stranded high voltage wire. The
wire uses 1/4" female quick connect on the electrode end
and female spark plug-type terminal on the ignition control
end.
NOTE-IN ORDER TO MAXIMIZE SPARK ENERGY TO
ELECTRODE, HIGH VOLTAGE WIRE SHOULD TOUCH
UNIT CABINET AS LITTLE AS POSSIBLE.
2-Flame Sensor
Flame is sensed by rectification through the flame sensing
electrode.
X-HEATING SYSTEM SERVICE CHECKS
A-A.G.A./C.G.A. Applications
and Requirements
All GCS24s are A.G.A and C.G.A. design certified without
modification.
Before checking piping, check with gas company or authori
ties having jurisdiction for local code requirements. Refer to
the GCS24 Operation and Installation Instruction Manual for
more information.