On Monday & Tuesday the operator had to respond to many HEPI Pressure alarms.  They did not appear real to me as they seem to be glitches and steps in the pressure, things that really don't happen.  At the time I associated it with all the electronics changes EE was doing.  I surmised the powering off and on as things were replaced was causing ground state shifts on the pump station controller in turn changing the pressure transducers response or offsets.

Checked the HEPI Platforms and they were off during the pressure transients so it was not the platforms de-isolating or re-isolating.  We'd have seen this before if it was that.

Attached are a few trend plots, but nothing is definitive.

The first attachment is the corner station.  I'm plotting the return and supply pressures at BSC2, the difference between them for the servo set point.  The VOUT controls the motor/pump speed and the last trace is the MAINSMON, something to do with the building power supply.  A few glitches occurred before lunch.   But at 1325 it appears the Return Pressure droops more than Supply increasing the differential pressure and the servo drops the speed of the pump to keep the DP correct and this continues down and then back up in a series of steps.  Further after lunch more steps are seen.  Interesting to see the MAINSMON go flat for a few hours (the data is there) and then glitch back to looking live just as the final pressure jump puts everything back to normal at 1740 on Tuesday.

The second attachment is for EndY but showing you fewer channels and including the HPI OUTF to show that the platform isolation is not the cause.  This story for EndY is similar to the corner station except it is pretty much a single step in the pressures and motor speed.  Again, everything jumps back to normal when the MainsMon comes back alive, hmm at 1740pdt.

For EndX, this occurred on Monday.  The picture isn't as clear (3rd attachment,) the sensors are much noisier at EndX and the MainsMon came back on a couple times.  The first step also occurs about the time Ken the electrician is at EndX for access system work (alog 18496.)  There is also correlation at one occurrence of the MainsMon coming back alive.

Can't say exactly what was causing these pressure glitches but the pump station really responds to them and had the platform been isolating, it would have been seen on them as the true differential pressure across the HEPI Actuator would change.

Bottom line, when Richard tells you it won't bother you or it isn't his fault, grab your salt shaker!