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Chapter 5. Trial Operation and Adjustment
z
Measurement of flame voltage
This device shows the flame voltage on the 7-segment display. The voltage can be
checked by changing the display using the DISP switch on the front of the unit.
Checking the flame voltage is the best way to determine whether or not the location
of the flame detector is appropriate.
The flame voltage should be checked during installation and servicing. Checking it
once per month or more can prevent shutdowns due to insufficient flame voltage.
Start the device and measure the voltage under various conditions, such as at
startup and during normal operation. Check to make sure that the flame voltage
remains stable at 2.0 V DC or more. (The recommended flame voltage is 2.0 V DC
or more and it must be stable.)
If this stable voltage cannot be achieved, the problem may be caused by one or more
of the following. In such a case, do a thorough inspection.
• The power supply voltage or frequency is not correct.
• The air supply pressure or air-fuel ratio is not correct.
• The flame detector is not correctly wired.
•
Open circuit
•
Short circuit
•
High-resistance short circuit of the lead wires due to humidity or dirt
• Incorrect flame detector mounting angle (AUR455C)
• Dirty flame detector sensing surface (AUR455C)
• Tube unit deterioration (AUR455C)
• Incorrect flame rod installation (AUR455B)
•
Area in contact with flame is insufficient.
•
Position of flame rod in flame is incorrect.
•
The flame rod insulator is at a high temperature (315 °C).
•
Flame rod is affected by the ignition transformer.
If the ignition transformer is close to terminal F of the flame rod, electrons
in the flame will be absorbed into the ignition transformer, and as a result,
sufficient flame voltage will not be achieved.
The voltage can be checked on the 7-segment display or by connecting a flame
meter to terminals 25 & 26 on the front connector. It is necessary to obtain a
monitor/communication connector (81447514-001) to connect the FSP136A100
and the AUR455.
Analog
flame meter
FSP136A100
Flame voltage
display
Handling Precautions
•
For the flame voltage output signal wires, use 600 V PVC-insulated cable (IEC
60227-3), 0.75 mm
2
or more in cross-sectional area. The wiring should be no
longer than 10 m.
•
The input impedance of a measuring instrument used with this device must
be 100 kΩ or more.
