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RGM Form 421, Mfg No. 150492, Page 17
Two-Stage with Intermittent Spark Pilot System with or without Lockout
W.D. 110824
G67BG-5
FLAME SENSING
BK
BL
IGNITOR
CHASSIS GRND.
G770NGC-4
IGNITION
LOCKOUT
RECYCLE
CONTROLLER
1
2
3
4
OR
GRND
PROBE
W
G
BR
GRND.
STRIP
BR
13
12
CR
BR
BR
BKBKO
O
40 VA. CONTROL
BK
BL
24V
LINE VOLT
BR
R
TRANSFORMER
Y
BKBK
LIMIT CONTROL
2 4
CONTACTS
VENTER RELAY
FOR WIRING)
WBK OR RBKBK
LINE/1/60
L2
(COM)
L1
(HOT)
OO
O
BL
PRESSURE
SWITCH
G
LINE GND
OPERATING SEQUENCE
1. SET THERMOSTAT SWITCH AT "OFF" POSITION.
2. TURN ON MAIN AND PILOT MANUAL GAS VALVES.
3. TURN ON POWER TO UNIT.
4. SET THERMOSTAT SWITCH AT "ON" POSITION.
5. LOW STAGE OF THERMOSTAT CALLS FOR HEAT ENERGIZING THE VENTER MOTOR.
6. PRESSURE SWITCH CLOSED ENERGIZING THE PILOT GAS VALVE AND SPARK GAP
TO PRODUCE A PILOT FLAME ON EACH OPERATING CYCLE. THE SENSING PROBE
PROVES THE PRESENCE OF THE PILOT FLAME AND ENERGIZES THE SAFETY
SWITCH PORTION OF THE CONTROL. THE SWITCH ACTION DE-ENERGIZES THE
SPARK GAP AND ENERGIZES THE LOW STAGE GAS VALVE.
8. IF THE FLAME IS EXTINGUISHED DURING MAIN BURNER OPERATION THE
SAFETY SWITCH CLOSES THE MAIN VALVE AND RECYCLES THE SPARK GAP.
ON UNIT EQUIPPED WITH G77ONGC-4 LOCKOUT CONTROL, IF PILOT IS
NOT ESTABLISHED WITHIN 120 SECONDS (APPROX.) UNIT LOCKS OUT
AND MUST BE REST BY INTERRUPTING POWER TO CONTROL CIRCUIT.
(SEE LIGHTING INSTRUCTIONS)
BR
BR
12
11
10
9
8
7
6
13
14
15
16
17
18
19
20
21
22
VENTER
RELAY COIL
9
7. HIGH STAGE OF THERMOSTAT CALLS FOR HEAT ENERGIZING THE HIGH STAGE
GAS VALVE, FIRING UNIT AT FULL RATE.
PILOT
HIGH
STG
3
4
LOW
STG
2
GAS VALVE
1
REDUNDANT
W.R. TWO STAGE
R
BR
W1
W2
Q674G SUBBASE
SET ANT. AT 0.8 AMPS
R
T874F THERMOSTAT
R
BL
OPTIONAL
BK OR R
(SEE NOTE #7
VENTER MOTOR
TOTAL WIRE MINIMUM RECOMMENDED
LENGTH WIRE SIZE
150 FEET #18 GA.
250 FEET #16 GA.
350 FEET #14 GA.
FIELD CONTROL WIRING
1. DOTTED WIRING SUPPLIED AND INSTALLED BY OTHERS.
2. CAUTION: IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE APPLIANCE
MUST BE REPLACED, IT MUST BE REPLACED WITH WIRING MATERIAL HAVING
A TEMPERATURE RATING OF A LEAST 105 DEGREES C., EXCEPT FOR ENERGY
CUT-OFF OR SENSOR LEAD WIRE WHICH MUST BE 150 DEGREES C.
3. LIMIT WIRE TO BE #18 GA. 200 C. SF-1 OF SEW-1.
4. USE #14 GA. WIRE FOR LINE WIRING TO UNIT.
5. LINE AND BLOWER MOTOR BRANCH CIRCUIT WIRE SIZES SHOULD BE OF A SIZE
TO PREVENT VOLTAGE DROP BEYOND FIVE PERCENT OF SUPPLY LINE VOLTAGE.
6. ON 208/230V. UNITS THE CONTROL TRANSFORMER HAS A DUAL VOLTAGE PRIMARY.
FOR 208V. UNITS USE BLACK AND RED LEADS (CAP YELLOW).
FOR 230V. UNITS USE BLACK AND YELLOW LEADS (CAP RED).
ON 115V. UNITS THE CONTROL TRANSFORMER IS SINGLE VOLTAGE PRIMARY.
USE BLACK AND YELLOW LEADS FOR 115V.
SECONDARY SIDE OF TRANSFORMER (24V.) USE BLUE AND BROWN LEADS.
ON 75-250 208V UNITS, THE VENTER MOTOR WIRES ARE BLACK AND WHITE (CAP RED)
ARE BLACK AND WHITE.
ON 75-250 230V UNITS, THE VENTER MOTOR WIRES ARE RED AND WHITE (CAP BLACK)
ON 75-250 115V UNITS AND 300-400 UNITS ALL VOLTAGES, THE VENTER MOTOR WIRES
7.
NOTES
WARNING: If you turn off the power supply,
turn off the gas. See Hazard Levels, page 2.
Access to
limit switch
from
"outside"
the furnace
18. Limit Switch
A non-adjustable high limit switch mounted at the outlet air side of the
heat exchanger acts to shut off the gas supply in the event of air handler
motor failure, lack of correct air flow (See Paragraph 13), or restriction
due to filters and/or duct design. See Figure 16 for mounting and ser-
vice.
Depending on accessibility, the limit switch may be serviced from ei-
ther the outside of the unit or from the inside through the access panel
in the discharge duct. When units are installed side by side, the service
access panel must be in either the top or bottom of the ductwork for
limit switch service. (See Paragraphs 8 and 11.)
Figure 16 - Access
to the limit switch
depends on the
installation
View of limit
switch from
"inside" the
furnace