Today we opened the PKR 251 pressure sensor (our high vacuum pressure sensor) to clean it and reassemble it. Understandably, taking it apart was a delicate procedure (following the manual) due to the strong magnet and easily breakable components.
Upon disassembling, we found a lot of debris that looked like pieces of metal film: very shiny. From what we could gather it seems to have peeled off the polarity insert, although we cannot be sure. After cleaning, however, the polarity insert appeared to look fine. Per instructions, we cleaned the following:
1. Rinsed the measuring chamber and polarity insert with a polishing cloth and isopropanol.
2. Soaked the Pirani element in methanol.
3. Soaked the ignition aid and the anode in methanol.
4. Rinsed the screws, washers, and seals with a polishing cloth and methanol.

Unfortunately, upon removing the anode from the beaker containing methanol, the anode was dropped and the metal pin snapped apart. This is unfixable. Thus, we contacted John at Pfeiffer again to get quotes on a replacement kit. Reassembling the pressure sensor will have to wait for another day. The components are currently bagged and lying upon the work bench. Do NOT move them.