We recently had several high cylinder pressure trips on one of our engines (it turned out to be a leaking exhaust gas bellows that damaged the wire to a SOGAV), Wartsila recommended changing the LT cooling water setpoint for our engines. The LT cooling water setpoint to the charge air coolers was set to 4C below the charge air dew point temperature, but Wartsila recommended changing it to 2C below dew point.
We made the change on one of our engines and noticed that the charge air cooler drains have no water coming out of them, when there used to be a steady flow of water.
What setpoint do most users have for their LT cooling water? Is it 2C or 4C?