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R4140G FLAME SAFEGUARD PROGRAMMING CONTROLS
60-2337—3
22
Fig. 14. Timer sequence for R4140G1148 Programmer.
Step-By-Step Operation (R4140G1148)
Start and Prepurge
0 seconds—On a call for heat, the burner controller
contacts close. If the limits and start interlock(s) are
closed and flame relay 2K is not holding in, relay 1K
pulls in through M7B, 2K2, the LS HTR (lockout switch
heater—thus proving its continuity), and LS2.
— 1K1 closes and 1K2 opens; timer motor starts
(through 1K1, M3A, and M5B); power is applied to
terminal 8, starting the burner motor (blower); 1K3
closes.
— Prepurge begins.
4 seconds—M10A closes, M10B opens; firing rate motor
drives toward high fire position (open).
— M1B closes, bypassing 1K1; the timer can
complete its revolution if shutdown occurs.
9.5 seconds—M7B opens; running interlocks must be
closed (airflow must be proven) or 1K drops out, 1K3
opens, and ignition trials cannot be started. Running
interlocks must remain closed through the Run period
or the system shuts down; the timer completes its
revolution and recycles the programmer.
15 seconds—M11B closes; flame relay 2K can pull in if a
flame (or a condition simulating a flame) is detected. If
detected during prepurge (until 57.5 seconds), 2K pulls
in, 2K2 opens, 1K drops out, and the system shuts
down; the timer completes its revolution and recycles
the programmer (if 2K drops out).
45 seconds—M10B closes; firing rate motor drives toward
low fire position (closed).
52 seconds—M3A opens; timer stops until the low fire
proving switch closes; timer can be stopped by opening
the timer switch (until 66 seconds when M3A closes
again).
57.5 seconds—M7A closes; the LS HTR (lockout switch
heater) begins heating in preparation for ignition trials.
M10058
TIMER
SECONDS
TIMER DIAL
TIMER
MOTOR
BURNER
MOTOR
(BLOWER)
INTERRUPTED
PILOT/IGNITION
5 SECOND
IGNITION
MAIN FUEL
VALVE(S)
(GAS OR OIL)
FIRING RATE
MOTOR
SWITCHING
ACTUAL
DAMPER
OPERATION
0 10 20 30 40 50 60 70 80 90 100 110 120
START
STOP
START
STOP
START
STOP
IGN
MAIN
PURGE
PREPURGE
6
RUNNING INTERLOCKS (PROVEN AIRFLOW)
MOTOR
DRIVES
DAMPER
OPEN
MOTOR
DRIVES
DAMPER
CLOSED
MOTOR DRIVES
DAMPER CLOSED
RUN
PERIOD
3
1
2
1
2
3
4
5
6
1
2
2
2
4
3
5
LOWLOW
15 SECONDS
7
8
18
5
5
12 TO 11
6
TERMINAL NUMBERS (CIRCLED).
SLOPE DEPENDS ON MOTOR TIMING.
TIMER STOPS AT 52 SECONDS UNTIL LOW FIRE PROVING
SWITCH CLOSES.
FIRING RATE MOTOR MODULATES UNDER CONTROL OF SERIES 90
CONTROLLER FROM 100 TO 112 SECONDS (INCLUDING RUN
PERIOD WHILE BURNER IS FIRING).
TIMER STOPS AT 104 SECONDS FOR THE RUN PERIOD WITH THE
BURNER FIRING.
RUNNING INTERLOCKS (INCLUDING THE AIRFLOW SWITCH)
MUST REMAIN CLOSED THROUGH THE RUN PERIOD.
HIGH FIRE POSITION
LOW FIRE POSITION
MODULATE
14 TO 11
10 TO 11
PILOT
10 SECONDS