Прошу помочь перевести фразу из руководства к ammonia plant

Experience has shown that a careful cleaning of OASE systems is not only indicated as good operating practice, but is mandatory to minimize foaming of the solution and delays in the initial start-up.
The time used in properly cleaning the OASE systems pays large dividends later on when process gas is admitted to the system for removal of CO2.
Therefore, special effort should be made to have the system as clean as possible before start-up.
***During the water wash circulation steps, instrument flushes, seal flushes, control valve, and instrument operation should be checked and adjusted as required for correct operation.

instrument flushes, seal flushes - относится к "during" или к "should be checked.."

Спасибо.