Honeywell 7800 Series Manual page 28

RM7888A
OPERATION
Fig. 21—DSI Normal sequence timing diagram.
65-0175
STANDBY
INPUT &
OUTPUT
SIGNALS
STANDBY-
PURGE
POWER
POWER
PILOT
FLAME
MAIN
ALARM
IGNITION- T10
PILOT- T8
MAIN- T9
AIR VALVE-T5
FLAME PROVEN- T21
ALARM- T3
MOTOR POSITION- T12-T15 L/H/MOD
@ LOW FIRE INPUT- T18
LIMITS COMPLETE- T7
SF1 SPECIAL FUNCTION- T6
SF2 SPECIAL FUNCTION- T17
SF3 SPECIAL FUNCTION- T19
SF4 SPECIAL FUNCTION- T20
FLAME SENSED
NORMAL- NORMAL- NORMAL-
PART 1 PART 2 PART 3
4 SECONDS, 5 SECONDS,
POSSIBLE POSSIBLE
0 TO
INFINITE INFINITE INFINITE
HOLD HOLD
SECONDS
POWER POWER
POWER
PILOT PILOT PILOT
FLAME FLAME FLAME
MAIN MAIN
L L MOD OR LOW
28
TO STANDBY
TO END OF PART 1
M9498