Problem :

JCW inlet temp shows very less & outlet shows very high.

In 1987, in one ship were I was sailing as 5th Engineer, this incident took place. Ship was in Japan & I was in night duty. Next day afternoon ship sailed out and I came down for watch at 1600hrs, observed JCW temp inlet was showing less than normal 48ºC, instead of 60ºC.

Also while checking found some units JCW outlet temperature had also gone upto 90ºC. Immediately unit air vent cock opened up found no water coming out & steam was found coming out. Pressure gauge was showing normal pressure.

So air vent cock kept open till water came out. After some time observed other units started having same problem. No work has been carried out either in the JCW pump or ME. So exact problem could not be found. In the mean time unit purging was on.

Half an hour later I changed over the pump & observed JCW parameters became normal. Further investigation revealed, the pump which was running earlier was rotating in wrong direction. In that ship all centrifugal pumps had butterfly valves with non-reurn flap valve on the discharge side. Wondering then how the ME was getting water and came to the conclusion that may be because of non-return valve was leaking & pump could deliver a little amount of water at the ME outlet side. Pressure gauge was also renewed. Anyhow there was no damage & voyage went off smoothly.

Cause :

After discussing found the same day morning Electrical officer carried out some repair work on the JCW pump burnt connection in the main switch board & wile connecting, by mistake one phase was connected wrongly.

Lesson Learnt:

After every pump motor o’hauling work or any other work related with pump electrical work, pump must be sarted & running direction to be checked. Also while opening up any electrical equipment, it is better to mark the terminals and tag the cables or wires
Batch - 45
hindustan institute of marine training chennai