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The current burner stage is usually shown on the NXD410 User Interface placed after the current
burner status. The following describes each possible stage.
Name
PPC4000
YB110
Description
LOW
P15.3
12
From YB110: Indicates to PPC4000 that purge is complete and go
to ignition position. While in AUTO directs PPC4000 to low fire
position (P03).
HIGH
P15.2
X
From YB110: Indicates to PPC4000 to move servos to purge
position.
AUTO
P15.4
11
From YB110: Indicates to PPC4000 that burner has completed
light-off sequence and is now in AUTO ready to modulate.
Low Fire
Start
P5.1
D
From PPC4000: Active when servos are at standby (P00). Active
when servos at their ignition positions and signals YB110 to being
PTFI light-off. During AUTO becomes active when AIR servo is
within 5 degrees of low fire.
High Fire
Switch
P5.2
8
From PPC4000: Active when servos at their pre-purge positions
(P01). Signals YB110 to begin purge time. During AUTO
becomes active when AIR servo is within 5 degrees of high fire.
Operating
Control
P4.3 - IN
P4.4 - OUT
3
From PPC4000: Operating control relay contacts to be placed in
L1-3 circuit of YB110. Signal YB110 to begin burner sequence.
Safety
Relay
P5.10 – IN
P5.9 - OUT
P
From PPC4000: Safety relay contacts to be placed in 3-P circuit of
YB110.
LOGIC
STATE
MESSAGE
DESCRIPTION
s01
STANDBY
s01
Burner is in off condition. Burner control switch is open. Keypad
Burner ON/OFF commanding burner off. Servos are in P00
position.
s02
WAIT FOR PURGE
s02
Command given to turn burner on. Wait for YB110 command,
terminal X
s03
N/A
Does not apply to PPC4000
s04
s05
s06
s07
MOVE TO PURGE
s07
Burner now on. Profile selected, command from YB110 terminal
X to PPC4000 P15.2 to move servos to pre-purge position
s08
PURGE
s08
Servo motors at purge position. PP4000 sends output from P5.2 to
YB110 to terminal 8 to start purge time.
s09
MOVE TO IGNITION
s09
YB110 purge time complete. Output on terminal 12 to PPC4000
P15.3, command servos to ignition position.
s10
IGNITION
s10
Servos at ignition position. PP4000 sends output from P5.1 to
YB110 to terminal D.
s11
N/A
Does not apply to PPC4000
s12
s13
s14
s15
MOVE TO LOW FIRE
s15
YB110 completes light-off sequence and moves to AUTO.
PPC4000 receives command on P15.4. Hold position for 10
seconds.
s16
AUTO
s16
No change in YB110. PPC4000 begins modulation to satisfy
demand.
s17
CYCLE COMPLETE
s17
Controlled shutdown: pressure/temperature satisfied, burner on/
off keypad commands burner off; servos moved to low fire for
assured low fire cutoff.
Lockout or burner limit open – move to s01
s18
LOCKOUT
s18
All lockouts go to this stage.
