[Richard L]

The FAV should not requirte any cleaning for the duration of itd service life, assuming the high purity of water and methanol is used.

If you have intermittent problems, it will be due to the internal epdm seal being compromised with hydrocarbon or other chemical intentionally, making it swelling up. Always buy seal cans of methanol and Di water.

The FAV cannot be opened up, the only wayt to clean ir is is by soaking it in pure methanol overnight, it might be able to drawn soem of the contaminants out of the seal.

There is a possibility of deris... remove the debris by reverse flow using the TST jumper. Don't it more than 10-20 seconds a time.