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Chapter 4. Explanation of Operation
WARNING
If lockout occurs, be sure to do a prepurge before restarting the system. If the combustion chamber
and gas flue are not ventilated to remove any unburned gas, the ignition process may cause an
explosion.
z
Operation when an ignition failure occurs (Non-recycling gas-fired combustion)
Input
AUR890 operation
Sequence
codes
Operation of external devices
Power ON
When approximately 8 seconds have passed after the power has
been turned on, the 7-segment LED display on the front panel of
the AUR890 shows the sequence code [- -].
- -
Burner operation
switch ON
- -
When the burner operation switch is turned
on, the blower starts to operate, and if the
limit and interlock conditions are normal, a
prepurge is done. After the prepurge, the
prepurge completion signal is turned ON.
Blower: operating
Controller ON
If the prepurge completion signal is ON and the controller is ON,
the internal circuits are checked during the start check.
P
1
Afterward a false flame check is conducted during the ignition
wait time.
P3
If the status is normal, the lockout time begins, relays K1, K2, K3
and K5 turn ON, the ignition transformer starts, the pilot valve
begins to open, and external timer TM1 turns ON.
P4
Ignition transformer : start
Pilot valve : open
(TM1 starts)
When the time set for TM1 has passed after the start of ignition
transformer operation, TM1's contacts turn off, the ignition
transformer ceases operation, and the pilot valve opens.
P4
Ignition transformer : stop
Pilot valve : closed
Alarm output : OFF
(TM1's contacts : OFF)
If the flame detector does not detect a flame within the lockout
time, relays K1, K2, K3 and K5 turn OFF, relay K6 turns ON, and the
alarm output turns ON.
The ALARM LED (red) on the front panel of the AUR890 lights up.
P4
/
E6
Ignition transformer : stop
Pilot valve : closed
Alarm output : ON
(TM1 stop)
Burner operation
switch OFF
P4
/
E6
Blower : stop
Contact reset or
main unit reset
switch: ON
Relay K6 turns OFF to turn OFF the alarm output.
The ALARM LED (red) on the front panel of the AUR890 turns off.
- -
Alarm output : OFF
––
P1
––
––
Stop
Star
t check
P3
Ignition standb
y
P4
Lockout timing
P4/E6
P4/E6
Lockout
Stop
AUR890
Prepurge time
(external circuit)
Start check + Ignition standby time
Approximately 3 s
Approximately 8 s
Lockout timing time 15 s
TM1 on delay time
Reset time
1 s or longer
[Input]
Power supply
[7-segment display]
Limit, Interlock
[Output]
Ignition transformer
Burner operation switch
Blower
Controller
Flame signal
RESET switch
[LED]
FLAME LED (Green)
Alarm output
Pilot valve
Main valve
ALARM LED (Red)
Содержание 81447514-001
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