Flow Problems; Flow Is Zero - Teledyne T400 User Manual

5.7.5 F P
LOW ROBLEMS
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 5.6.6. If this test shows the flow to be correct, check the pressure sensors as
described in Section 5.7.9.7.
In general, flow problems can be divided into three categories:
• Flow is zero (no flow).
• Flow is greater than zero, but is too low, and/or unstable.
• Flow is too high .
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 5.6.6 is essential.
The flow diagrams found in Section 2.3.3 can help in trouble-shooting flow problems.

5.7.5.1 FLOW IS ZERO

The unit displays a SAMPLE FLOW warning message on the front panel display or the
SAMPLE FLOW test function reports a zero or very low flow rate.
Confirm that the sample pump is operating (turning). If not, use an AC voltmeter to
make sure that power is being supplied to the pump if no power is present at the electrical
leads of the pump.
1. If AC power is being supplied to the pump, but it is not turning, replace the pump.
2. If the pump is operating but the unit reports no gas flow, perform a flow check as
3. If no independent flow meter is available:
4. If gas flows through the instrument when it is disconnected from its sources of zero
083730400A DCN8130
described in Section 5.6.6.
Disconnect the gas lines from both the sample inlet and the exhaust
•
outlet on the rear panel of the instrument.
Make sure that the unit is in basic SAMPLE Mode.
•
• Place a finger over an Exhaust outlet on the rear panel of the instrument.
• If gas is flowing through the analyzer, you will feel pulses of air being
expelled from the Exhaust outlet.
air, span gas or sample gas, the flow problem is most likely not internal to the
analyzer. Check to make sure that:
• All calibrators/generators are turned on and working correctly.
• Gas bottles are not empty or low.
• Valves, regulators and gas lines are not clogged or dirty.
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