6.6 Installing and Commissioning the AcuDew Transmitter
It is advisable to carry out an initial purge routine of the sample loop, before
installing the sensor, in order to remove the possibility of sensor damage on start-up.
Refer to the sample system schematic on page 18 of this manual and open the inlet
isolation valve slowly, until a small flow of air/gas at atmospheric pressure flows
through the inlet pipework to the sensor holder and exhausts through the sensor
entry port of the sensor holder.
Allow this purge to continue for about 15 to 20 minutes to remove any residual
moisture from the sample pipework and components.
Close the inlet isolation valve, install the sensor into the sensor holder and ensure
that the sensor cable connector is correctly positioned, that the sealing cup is in
place and the retaining screw is screwed down securely to create a weatherproof
seal.
Open the inlet valve slowly again and, by opening all valves after the sensor holder,
allow a low-pressure purge through the whole sample system.
Note:
If a closed by-pass loop is installed, this section of the procedure is not
possible.
Set the required pressures and flows within the sample loop.
This completes the installation and commissioning but, on initial start-up, it could
take several hours for the system to reach equilibrium, depending on the number
and type of components used in the sample loop.
The instrument will now indicate the dew/frost point of the air/gas surrounding
the sensor, at sensor pressure and the analogue output will be giving a mA signal
proportional to the indicated dew/frost point or other engineering units.
6.7 Operation
The system is designed to operate continuously, with a minimum amount of
operator input.
It is, however, advisable to inspect the sample loop periodically to ensure that the
required pressures and flows are being maintained.
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