083730300A DCN8101 Maintenance and Service 121
LED FUNCTION
DIAGNOSTIC TECHNIQUE
D7
Green
Shutoff Valve
Option
SHUTOFF_VALVE N/A
Shutoff Valve should audibly change states. If not:
Failed Valve
Failed Relay Drive IC on Relay Board
Failed Relay Board
Faulty +12 VDC Supply (PS2)
Faulty Connectors/Wiring
D8
Green
IR SOURCE
IR_SOURCE CO_MEASURE
Voltage displayed should change. If not:
Failed IR Source
Faulty +12 VDC Supply (PS2)
Failed Relay Board
Failed IR Photo-Detector
Failed Sync/Demod Board
Faulty Connectors/Wiring
5.7.9 FLOW PROBLEMS
When troubleshooting flow problems, it is a good idea to first confirm that the actual
flow and not the analyzer’s flow sensor and software are in error, or the flow meter is in
error. Use an independent flow meter to perform a flow check as described in
Section 5.6.4. If this test shows the flow to be correct, check the pressure sensors as
described in Section 5.7.14.11.
The T300/T300M has one main gas flow path. With the IZS or zero/span valve option
installed, there are several subsidiary paths but none of those are displayed on the front
panel or stored by the DAS.
With the O
2
sensor option installed, third gas flow controlled with a critical flow orifice is
added, but this flow is not measured or reported.
In general, flow problems can be divided into three categories:
• Flow is too high
• Flow is greater than zero, but is too low, and/or unstable
• Flow is zero (no flow)
When troubleshooting flow problems, it is crucial to confirm the actual flow rate without
relying on the analyzer’s flow display. The use of an independent, external flow meter to
perform a flow check as described in Section 5.6.4 is essential.
The flow diagrams found in a variety of locations within this manual depicting the
T300/T300M in its standard configuration and with options installed can help in trouble-
shooting flow problems. For your convenience they are collected here.
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