SL2018-658/PRP INDICATOR VALVES PMI SENSORS

Updated instruction for indicator valves. By following precautionary measures and actions as recommended by MAN Diesel & Turbo increased safety and reliability
can be achieved.

Recently, we have received reports of a few incidents with damaged indicator valves that involved a potential risk of damage to property and serious personal injuries.

The long-standing service experience of MAN Diesel & Turbo approved indicator valves is generally very good and shows a low failure rate. Nevertheless, a service letter (SL2016-621) concerning the PMI sensors, introducing proper precautions for use, was issued due to reported failure incidents relating to the usage of the indicator valve.

However, as the indicator valve is used on all MAN B&W engines, this service letter provides a general update of the required safety information.

The temperature in the valve arrangement increases dramatically if the indicator valve is opened while the engine is running.

Therefore, it is recommended only to open the indicator valve while the engine is turned by air or by turning gear. Blow-through of the indicator valve is recommended during slow turning.
However, opening of the indicator valve is of course allowed when the valve is connected to measuring instruments (PMI or similar).