How to switch dual filters in a compressor system online

What does the original poster mean by that? There is a handle; just twist it 180°

Be careful with exhaust; otherwise it will cause a shutdown due to low oil pressure

If the original poster is asking about cartridge dual-filter units, the balance valve on the filter should be opened before making the switch. Once both cartridges are filled with liquid, the handle can then be turned to make the switch; this helps to reduce pressure fluctuations during the switching process, thereby avoiding various problems that may arise in the pipelines due to these pressure changes. Finally, if the purpose of the switch is to replace the filter element, the balance valve should be closed after the switch is made, and the built-in drain valve of the filter should be opened to drain all the liquid from the tank before proceeding with the replacement. The above procedures are applicable only in situations where the medium is safe; in cases involving high temperatures, high pressures, or toxic and explosive materials, the safety of performing an online switch relies on the sealing quality of the filter.

One more thing: be quick when making the switch, and do it in one go. There have been cases where a stop occurred due to oil pressure fluctuations during switching.

During the switch, the inlet and outlet valves should operate simultaneously; otherwise, a sudden drop will cause the unit to trip via interlock.