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ST7997 OIL BURNER MOUNTED ELECTRIC FAN TIMER
T
R7997
INTEGRATED
OIL PRIMARY
WITH BLOWER
DELAY
Fig. 4. ST7997 Oil Burner Mounted Electronic Fan Timer wiring for units with pre- and post purge.
NOTE: Two dummy quick connect terminals, labeled
"unused wires", not connected to the ST7997
circuitry, are provided on the back of the case to
hold unused wires from the circulation blower
motor speed taps.
IMPORTANT
Field changes to the speeds (low, medium low,
medium high, high) of the ST7997 blower modes
(heat, cool, or continuous fan) can be made to
models using Molex® connectors by cutting
speed wires and splicing in an unused lead in
accordance with local and national codes.
69-1204
HUMIDIFIER
EAC
T
OIL
VALVE
CIRCULATOR
LIMIT
BLOWER
(LINE
VOLTAGE)
HEAT CALL
LIMIT
CONTROL
ISOLATION
ELECTRONICS
K1
BURNER
MOTOR
Wiring Options
Wiring options are listed in Table 1.
Setting the Heat Fan-Off and Heat Fan-On
Delay Switches
Set the Heat Fan-Off delay switches to 60, 90, 120 or
150 seconds. See Fig. 6. The off delay time starts when
the burner motor is de-energized at the end of a thermo-
stat call for heat.
4
R
W
F1
RC
RC
C
G
G
C
RC
G
Y
Y
Y
THERMOSTAT
5-WIRE
K2
OEFT
ST7997
COMPRESSOR
CONTACTOR
J-BOX
SCREW TERMINAL
1/4 IN. QUICK CONNECT
L2
L1
GND
M12922
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