Teledyne T200, Руководство по эксплуатации, Страница: 240 / 425

Troubleshooting & Service Teledyne API
– T200 NO/NO2/NOx Analyzer Operation Manual
238
12.4. GAS FLOW PROBLEMS
The T200 has two main flow paths, the sample flow and the flow of the ozone supply
air. With IZS or zero/span valve option installed, there is a third (zero air) and a fourth
(span gas) flow path, but either one of those is only controlled by critical flow orifices
and not displayed on the front panel or stored to the DAS.

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 essential 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 11.3.12.3 is essential. Refer to
the pneumatic flow diagrams as needed for reference.
12.4.1. ZERO OR LOW FLOW PROBLEMS
12.4.1.1. SAMPLE FLOW IS ZERO OR LOW
The T200 does not actually measure the sample flow but rather calculates it from a
differential pressure between sample and vacuum manifold. On flow failure, the unit
will display a
SAMPLE FLOW WARNING on the front panel display and the
respective test function reports XXXX instead of a value “0”. This message applies to
both a flow rate of zero as well as a flow that is outside the standard range (350-600
cm³/min).
If the analyzer displays XXXX for the sample flow, confirm that the external sample
pump is operating and configured for the proper AC voltage.

Whereas the T200 can be internally configured for two different power regimes
(100-120 V and 220-240 V, either 50 or 60 Hz), the external pump is physically
different for each of three power regimes (100 V / 50 Hz, 115 V / 60 Hz and 230 V /
50 Hz).

If the pump is not running, use an AC Voltmeter to ensure that the pump is supplied
with the proper AC power. If AC power is supplied properly, but the pump is not
running, replace the pump.
Note Sample and vacuum pressures mentioned in this chapter refer to operation of the
analyzer at sea level. Pressure values need to be adjusted for elevated locations,
as the ambient pressure decreases by about 1 in-Hg per 300 m / 1000 ft.
If the pump is operating but the unit reports a XXXX gas flow, take the following three
steps:
1. Check for actual sample flow.

To check the actual sample flow, disconnect the sample tube from the sample
inlet on the rear panel of the instrument.

Ensure that the unit is in basic
SAMPLE
mode.

Place a finger over the inlet and see if it gets sucked in by the vacuum or, more
properly, use a flow meter to measure the actual flow.

If there is proper flow of around 450-550 cm³/min, contact customer service.
06858E DCN7057