Adam and Janos

I inspected all installed HEPTA controllers and found all but the Y-mid to be satisfactory. We ran a test on the X-mid to verify thermal switch operated correctly by letting the pump heat up to ~100c. 

The corner station controller that the failed HEPTA was installed on passed all electrical tests. It is my belief that the failure was due to a mechanical defect inside the pump its self.

I inspected the "OMC" turbo controller that was having a issue with indicating lights and identified the issue of a missing component on the back of the indicating light. See address below

https://www.digikey.com/en/products/detail/siemens/3SU14001CK101AA0/15237249


Lastly, I inspected the Y-mid controller and prior to opening the panel I already found red flags such as an electrical connector for a solenoid operated gate valve that does not exist at the HEPTA stations wired into the panel. After opening the panel I noticed an entire relay added to the left side of the panel and wired in that is not part of any wiring diagram and a third small CPC drilled and added in to the bottom of the panel for GV indication which was not necessary as one of the originals is now spared. The extra relay was being used to detect the status of the small solenoid that controlled air flow to the pneumatic gate valve at the HEPTA inlet. We don't care about the status of the solenoid only the status of the GV which is already measured directly from the internal contacts of the GV. This relay only added another failure point for the opening of the GV and has since been removed. I found about 7 wires that were not secured and either pulled out or fell out of their terminals. I found one relay with a normally open and a normally closed contact wired in parallel. This is a logical fallacy as it will always conduct and provides no more control that just a straight wire.

I reconfigured the Controller per the wiring diagram and ran a stop work approved test and all systems that were available to test passed. I was not able to test the complete functionality of the GV as there was no instrument air available but the controlling solenoid did function so i have no reason to believe that the GV would not function. Lastly the thermal switch could not be tested as the pump could not run in the appendix configuration.