Exploitation

Low temperature fresh water cooling circuit preparation and operation procedures:
a)  Make sure that the level of the FW expansion tank is correct, top up with fresh water from the engine room if necessary.
b)  Make sure that all pressure gauges and instrument valves in the LT cooling circuit are open.
c)  Switch the valves as shown in figure below.

Example of commissioning of a low temperature fresh water cooling circuit

d)    Start one LT fresh water circulation pump.
e)    Turn on the overboard water cooling system if it is not already running and supply the on-board water to the central FW cooler.
NOTE: The coolers are put into operation by manually setting the respective inlet and outlet valves.
f)     Check the system for leaks and rectify any leaks.
g)    Check the concentration level of the corrosion inhibitors and add the chemicals required for treatment if necessary.
NOTE: To reduce the likelihood of corrosion, the cooling water in both cooling systems is treated with inhibitory chemicals. Cooling water shall be tested in accordance with the requirements of the chemical supplier's and the company's operating procedures. After any necessary chemical treatment, it is necessary to record this by indicating the amount of chemicals added to the fresh cooling water expansion tank.
h)    Check that one of the non-functioning LT FW circulation pumps is in automatic standby mode.
NOTE: If required, the LT FW boost pump can be switched on to boost the cooling water supply to the service group. If the cooling demand is low, the cooling water demand can be met by using a boost pump bypass valve and the boost pumps can be stopped.