R4140G FLAME SAFEGUARD PROGRAMMING CONTROLS
60-2337—38
Ignition Trials
60 seconds—M4A closes; power is applied to terminals 5
and 6, energizing the ignition transformer and pilot
valve (or main fuel valve(s) on terminal 7 if using direct
spark ignition).
—When a flame is detected, relay 2K pulls in, 2K2
opens, and the LS HTR stops heating; 2K1 and
2K3 close.
66 seconds—M3A closes, bypassing the low fire switch
and the timer switch.
70 seconds—M2B opens; pilot or ignition trial ends; a
flame must be detected by this time (2K pulled in and
2K1 closed) or safety shutdown occurs and the lockout
switch trips.
—M2A closes; power is applied to terminal 7,
energizing the main fuel valve(s).
—M11B opens; prevents 2K from pulling in after this
time.
80 seconds—M6B opens; 10 second interrupted pilot/
ignition (terminal 5) is de-energized.
100 seconds—M4A opens; 30 second interrupted pilot/
ignition (terminal 6) is de-energized.
—M8A closes, M8B opens; firing rate motor is
released to modulate under control of the Series 90
Controller.
104 seconds—M5B opens; timer stops with the system in
the Run condition.
Run Period (Burner is Firing)
Postpurge And Stop
104 seconds—When the operating setpoint is reached, the
burner controller contacts open; relay 1K and the main
fuel valve(s) (terminal 7) de-energize.
—1K2 closes; timer motor starts; postpurge begins.
—When the flame goes out, relay 2K drops out.
112 seconds—M8A opens; firing rate motor stops
modulating under control of the Series 90 Controller.
116 seconds—M8B closes; firing rate motor drives toward
low fire position (closed).
120 seconds—M1B opens; timer and burner motor stop;
cycle ends.
Fig. 5 shows all contacts in the standby position (zero
seconds). The opening and closing times are shown adjacent
to each timer contact. Refer to Fig. 6 and the Step-by-Step
Operation section.