What procedures and precautions required when cleaning both air and water sides of a charge air cooler?
Cleaning Air Side
On a large 2 stroke crosshead engine the air cooler may be cleaned by injecting an air cleaner chemical into the charge air while the engine is running. The chemical used is hazardous to health and thus protective clothing must be worn, and manufacturers instructions followed. Alternatively, a system using a chemical circulating tank, pump, and built-in sprays may be used when the engine is stopped. After circulating the chemical for a period of time as instructed, the air cooler must be rinsed using fresh water. Ensure drains from the air cooler to bilge are clear. On a medium speed engine, the air cooler can be cleaned in situ (with the engine stopped) by blanking the air inlet and outlet and filling with a cleaning solution. However, it will be necessary to support the air cooler, as the fastenings used may not be designed to cope with the extra weight. However, it may be easier to remove the whole air cooler and place it in a bath of cleaning solution. A protective clothing must be worn, and suitable ventilation provided. It is normal practice to pressure test the cooler stack when it is in the rinsing bath to check for leaking tubes.
Cleaning Water Side
This is normally done in situ with the engine stopped. After isolation and draining, the end covers on the cooling water boxes are removed and the cooler is rodded through or blasted using a pressure lance. In the case of the latter suitable protective clothing must be worn. Cleaning the waterside is normally only carried out on air coolers using seawater, sacrificial anodes should be inspected and replaced as necessary.
