Azbil AUR450C - Chapter 3: Operation; Interrupted Pilot System Configuration Example; Interrupted Pilot Instrumentation Precautions

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Chapter 3. OPERATION
 Example of instrumentation for the Model AUR450C with an interrupted pilot
Air pressure lower limit
interlock
Gas pressure lower limit
interlock
Gas pressure upper limit
interlock
Ignition
transformer
Air
Gas
MV1 MV2
PV1 PV2
T/C T/C
L
L
H
UV
Controller
Overtemperature limit
Vibration
detection limit
Combustion
chamber
Combustion
equipment
Exhaust damper
interlock
Flue
duct
Burner controller
BC
(AUR450C)
Limit/Interlock
PS
PS
IG
PS
TIC
TIA
Flame
detector
Exhaust
gas
Vibration
detector
 Precautions for instrumentation and circuit configuration with an interrupted pilot
In instrumentation and circuit configuration of the device with an interrupted pilot
valve, note the following:
•
For safety control and operation circuits, devise a safety plan based on risk
assessment.
•
Configure the interlock (including limit) contacts so as to directly disconnect
loads (ignition transformer, pilot safety shutoff valve, main safety shutoff valve,
etc.).
•
Design a circuit that shuts down all the burners when a ignition failure or a flame
failure of the pilot or main burner occurs.
•
Install all the interrupt contacts on the high potential (non-ground) side of the
power supply.
•
As needed, take preventive measures against electrical leakage, such as using an
electrical leakage breaker or a double pole contact system.
•
Do not configure a circuit that turns off the interlock input (terminals 17-18)
using the alarm output contacts (terminals 11-12). With such a circuit, if a false
flame, UV alarm, ignition failure, or flame failure occurs, the interlock alarm may
be displayed.