INITIAL STARTING.— All external surfaces of the pump should be carefully cleaned before the pump is started. If the factory assembly has not been dis- turbed, it will not be necessary to dismantle the unit for cleaning. The interior of the pump was coated with a special rust-preventive compound after the factory test. The removal of this compound is effected com- pletely without any harmful results in the normal operation of the unit. Make sure that the shaft packing has been in- stalled and that the gland nuts are only fingertight. Before you start the pump, prime it by filling the pump case and as much of the suction line as possible with oil. If the air is not removed from the suction line, the performance of the unit will be erratic, or it will not pump at all. If no priming connection is provided, use the plug on the suction connection of the pump. Open the suction, discharge, and vent valves and start the motor. If the pump is moving the oil satisfac- torily, the vent valve may be closed after a few min- utes of operation. Allow the shaft packing to leak freely for the first 15 minutes of operation; then, tighten the gland nuts with your fingers until there is only a slight leakage past the packing. If the pump fails to discharge after starting, stop the motor, prime the pump again, and restart the pump. If it still does not pickup oil immediately, there may be a leak in the suction line, or the trouble may be traced to excessive suction from an obstruction, throttle valve, or other causes. Connecting a gage at several points along the suction line, while the pump is operating, helps locate the trouble. An obstruction in the suction line causes an observable drop in pres- sure at the point of obstruction, the lower pressure being on the pump side. CAUTION Operating the pump without oil causes rapid wear of the housing and bearings; there- fore, checks for trouble must be made quickly and systematically. ROUTINE STARTING.— Open the suction and discharge valves and start the motor. Ensure that oil is being pumped and that there is a slight leakage past the shaft packing. Read the gages that indicate the suction and discharge pressures for the pump, and make sure the pump is operating normally. If it is not pumping, follow the instructions for initial starting. OPERATION.— After the pump is in service, it continues to operate satisfactorily with little or no need for maintenance except normal PMS. The suc- tion and discharge pressures should be checked at least every 10 minutes to verify the performance of the pump. Once each day, the shaft packing should be inspected to see that it is properly adjusted. Any un- usual conditions should be noted and investigated. SECURING.— Stop the motor and close the suc- tion and discharge valves. Maintenance De Laval pumps require very little attention in normal usage. Unless they are operated without oil or with oil containing abrasive particles, their operation without major overhaul is virtually unlimited. The pump is equipped with a relief valve to pre- vent excessive oil-pressure buildup. The relief valve also seals the metallic packing against air leakage during suction lift conditions. There is a set of packing located in the packing box end cover (fig. 6-3). The four flexible, metallic packing rings are installed with the joints of abutting rings staggered, and they are held in place by a pack- ing gland. This packing gland is split to allow packing replacement without disturbing the other elements of the pump. The two sections of the packing gland are held together with two screws, and the gland pressure is adjusted with two gland nuts. This adjustment should be sufficient to allow a slight amount of leak- age past the packing for lubrication of the packing. Inspection An inspection made while the pump is operating discloses any leakage between the end covers and case or in the piping connections. If leakage is ob- served, it may be due to foreign matter on the gaskets, defective gaskets, or loose nuts and bolts. Replace the gaskets or tighten the nuts and bolts as required. Lubrication The pump does not require any lubrication, since the oil being pumped lubricates all the moving parts. Driving-unit lubrication instructions are provided with each unit. 6-4