The CUNO filters were changed 2023-01-17 for:

• BL1A Holding Tank drain output, adjacent to the pump
• RH Active Sump, adjacent to the V2 valve

Both of these filters are in-line with the drainage lines from the BL1A holding tank to the active sump. It was suspected that they have not been changed in many years, if ever. Prior to changing the filters, the maximum flow rate measured from the Proteus paddle wheel sensor during draining was around 0.85 gpm (the draining procedure document indicates it should be between 0.9 to 2.5 gpm). After replacing both filters, which each showed significant clogging of sediment, the flow rate significantly increased and the maximum of 2.5 gpm was achievable. Note that when the drain pump was initially turned on, it took some time to reach the desired flow rate due to air in the water lines - the flow rate was quite low until the lines were once again filled with water.

It is suggested that these filters should be replaced every ~3-5 years, depending on usage, or otherwise as-needed (it is possible to see through the clear walls and determine how dirty they are). This MRO item will be added to the checklist of routine T1/T2 related tasks performed to prevent flow rate issues in the future during draining.

Filters were bagged and discarded as active waste.

Attached photos show old filter in bucket, and newly replaced filter, for the RH Active Sump.