Det-Tronics U7652B, C Unitized UV/IR Flame Detector User Manual

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Table 7—Automatic

Troubleshooting

Fault

Indication

Corrective Action

UV Fault

• Fault relay de-energized

• Clean the viewing window and

ring of the UV sensor.

• UV sensor LEDs not blinking • Check the

ring opening for proper orientation. See

Figure 2.

If the fault does not clear (UV fault reoccurs after
approximately 3 minutes):
• First replace the UV sensor module.
• If the problem persists, contact the factory.

IR Fault

• Fault relay de-energized

• Clean the viewing window and

ring of the IR sensor.

• IR sensor LEDs not blinking

• Check the

ring opening for proper orientation. See

Figure 2.

If the fault does not clear (IR fault re-occurs after
approximately 3 minutes):
• Check the connection and condition of the IR module

connector plug and wires. Repair or replace if needed

• If the problem persists, replace the IR sensor module.
• If the problem still persists, contact the factory.

General Fault

Fault relay de-energized

Check input power to the detector as well as continuity of

LEDs not blinking

system wiring.

Also check the detector viewing windows for contamination
such as paint overspray, dirt, etc. that could simultaneously
affect both sensors. Since simultaneous failure of both sen-
sor modules is unlikely, the problem is most likely caused by
loss of input power or failure of the detector motherboard.

Background

The presence of background

Background radiation as such does not cause a problem

Radiation

UV or IR radiation is indicated

with the detector in most applications, unless both UV and

by steady illumination of the

flickering IR non-fire radiation sources occur simultaneously.

LEDs at either of the sensors.

If a UV or IR background radiation indication occurs:

The Fault and Fire relays are

• Determine its cause. The presence of background

unaffected.

radiation could indicate a problem in the protected area.
For example, background UV could be caused by welding.

• Determine whether or not repositioning the detector could

eliminate response to the background radiation without
reducing coverage of the hazardous area.

• If the UV or IR LEDs are on and it is determined that no

background UV or IR source exists (by shielding the view
of the detector), the problem could be in the sensor mod-
ule, motherboard assembly or detector wiring.

IR Fault upon

• Fault relay de-energized

The detector will function in this condition. However, it is

Power-up

• IR sensor LEDs on

essentially functioning as a UV only detector, since the IR

continuously

sensor is continuously sending a fire signal. A fire signal
will override a fault signal. This can make the detector
more susceptible to false alarms caused by non-fire UV radi-
ation sources such as welding. If the IR sensor returns to
normal operation (no longer in an alarm condition), the
microprocessor will recognize this and the fault will be
cleared. If not, the usual corrective action is replacement of
the IR sensor module.