Kyle, Gerardo

Upon being notified of the upcoming (unscheduled) vent of HAM6 on Monday, we thought that it would be prudent to run the Corner Station purge air supply sooner rather than later do demonstrate its readiness.  Though this unit is well maintained and hasn't had functional issues of late, it is 20 years old now and we no longer assume that it won't develop issues while sitting idle.  As such, we found that it tripped off a few minutes after startup with the alarm "2nd STAGE SUCTION OVER TEMPERATURE".  Restarted and same problem etc ->  The water lines supplying the intercooler were colder than ambient suggesting chilled water flow to the components of interest (Yes John the booster pump is on!) -> The displayed temperature of interest was intermittently alternating between an expected value and a bogus high value which resulted in the shut down response -> We switched the terminations between the 2nd stage suction RTD and discharge RTD and noted that the problem did not follow the temperature sensing device but rather remained "2nd STAGE SUCTION OVER TEMPERATURE" -> Gerardo noticed that when the bogus 2nd stage suction temperature value was occurring, that all of the other displayed temperatures also changed to the same value suggesting a logic and/or common connection issue.  Correspondence with Roger's Machinery (original equipment provider) revealed that the Siemens PLC unit used in our Kobelco had known issues that could sometimes be resolved by lifting then re-landing the wires (of which there were many!) on its terminal strips -> We did this and the unit seems to be happy now -> We are leaving it run over night but isolated from the LVEA so as to reduce air demand and minimize loading cycles. 

All of the Roger's Machinery field service technicians are booked solid through this weekend but I will be updating them at 0800 tomorrow morning as an emergency service call isn't out of the question should we need it.