[Dsg-rich] [New Logentry] RICH compressor pressure decrease investigation

[tlemon at jlab.org]

Logentry Text:
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Valery called notifying of low air pressure alarms for RICH's air cooling system. RICH air cooling buffer tank pressure had been steadily decreasing and was alarming at ~30 psi.

At Valery's direction, we made an access to the hall to investigate the cause.

In the hall, we noted that both the local pressure gauge on the cooling system buffer tank and the pressure readout on the compressor read ~80 psi (Fig 1 and Fig 2 in attachment). Because these two readouts match, it appears that the pressure transducer used for remote monitoring is not working correctly.

We left the compressor running and the system as we found it because:
1.) the cooling panel's regulators are set to lower than 80 psi (~35 psi for airflow 1 and ~30 psi for airflow 2; Fig 4 in attachment)
2.) airflows are close to their 500 slm and 400 slm set points (Fig 3 in attachment)
3.) the compressor's output pressure readback plot shows the pressure has been stable at ~80 for several days (Fig 2 in attachment). 

For now, Valery will lower the air pressure alarm and trip level to avoid the system giving further alarms or tripping off the detector. Airflow interlocks will remain at the same level.

After the run, we will look into replacing the pressure transducer on the buffer tank and look further into why the compressor output pressure has dropped.

As a side note, we also noticed the gauge on the compressor's output filter was in the red (Fig 5 in attachment). This will also be investigated after the run to see if the filter needs to be drained.

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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3677358
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