Kyle, Chandra

We plan to initially install this unit on CP4's exhaust with CDS power and signal read back so as to accumulate data from a typical "representative" 80K pump.  After which, we would then install it on CP3's exhaust and use it as part of a low-tech control loop to keep CP3's LN2 level within an acceptable range without the need to manually overfill it every few days.  Recall that one of the LN2 level transducer sensing lines (at lowest point of pump's LN2 reservoir) used to determine CP3's LN2 level became clogged in Dec. 2015 rendering the normal CDS PID control loop non-functioning and requiring manually filling the pump every 72 hours.  

Today we just wanted to install it temporarily to verify that the resulting back pressure was as advertised by the manufacturer.  The "before" exhaust pressure was nominally 1.0 psig and the "after installation" value increased 0.1 psig to 1.1 psig - this is as advertised.  After a few hours however it looks like it causes periodic "spikes" in the exhaust pressure.  Since the exhaust pressure is one of the two differential values used to determine the 80K pumps level, we also see these spikes in the pump level (see attached).  I later removed the unit and restored the piping to as found.