Maintenance; Maintenance And Calibration; Fault Conditions - Michell Instruments Pura User Manual

Pura Advanced Online Hygrometer User Manual
4

MAINTENANCE

4.1

Maintenance and Calibration

Routine maintenance of the Pura Transmitter is confined to regular re-calibration. For
most applications, annual re-calibration ensures that the stated accuracy of the Pura
Transmitter is maintained.
Specialist calibration instrumentation is required to calibrate the transmitter and a true
calibration can only be performed by exposure of the dew-point sensor to a reference
gas of known dew point.
Calibration services are offered by Michell Instruments at their accredited calibration
laboratories. All calibrations are traceable to national standards either via the National
Physical Laboratory (UK) or the National Institute of Standards and Technology (USA).
The Pura transmitter can be returned to Michell Instruments either directly or via the
authorized distributor, for calibration.
Alternatively, Michell Instruments can provide an exchange transmitter. Prior to re-
calibration, an exchange transmitter can be ordered from Michell Instruments or an
authorized distributor.
Once the replacement transmitter and calibration certificate have been received, the
original transmitter can be disconnected and the replacement transmitter fitted in its
place. The original transmitter should be packed in its original packing, if possible, and
returned to Michell Instruments, either directly or via an authorized agent.
VCR Gasket
VCR gaskets should be replaced every time any VCR connection is re-made. Replacement
VCR gaskets can be obtained from Michell Instruments.
O-ring Seal
If the supplied O-ring seal is damaged or lost a pack of 5 replacement O-ring seals
can be obtained by contacting your Michell Instruments representative.
4.2

Fault Conditions

Display
OPEN
FAIL
0.0
Michell Instruments
Cause
Transmitter failure
Instrument failure
Transmitter failure
Gas is wetter than -40 °C
(-40 °F) dew point
Transmitter contaminated
MAINTENANCE
Action
Check power supply to transmitter.
Check sensor cable for continuity/
damage. Rectify/replace cable
Refer to Michell or local representative
for repair
Replace transmitter
Check gas source supply
Replace/re-calibrate transmitter
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