Start-Up - Universal Analyzers 270SF Instruction Manual

7.0

Start-Up

Apply power to the Model 270. Allow fifteen to twenty minutes for the filter to come to temperature. This
warm-up period is extremely important to avoid the condensation within the Model 270 filter which would
cement the particulates to the filter surface.
Start the sample pump and determine that the proper amount of sample is being supplied to the
instrumentation.
Perform a calibration cycle to ensure that the calibration lines are properly installed and sealed. A flow meter
should be installed in the calibration gas supply line to ensure that there is at least 10 percent more calibration
gas being supplied to the Model 270 than is being withdrawn as sample. This will ensure that the filter and
probe are being properly flooded with calibration gas. The excess calibration gas will pass through the probe
tube into the stack.
Open the instrument air valve to charge the blowback accumulator. Exercise the blowback solenoid valve to
insure it is properly wired. After a blowback cycle, the presence of a slight pulse on the sample tubing in the
analyzer shelter and the momentary dilution of the sample with instrument air is normal and signifies that a
blowback cycle has occurred.
The optimum time between blowback cycles is to be determined by experience, once a day is sufficient in
relatively clean applications. The requirement could be as frequent as every fifteen minutes where the dust
and soot levels are severe. It is better to blowback too often than not often enough. A vacuum gauge in the
sample line can be helpful to indicate if the particulate loading of the filter has started to restrict the flow of
sample. The blowback cycle should be initiated before unacceptable pressure drop occurs.
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