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The sight feed lubricator should be filled in the morning so as to be empty by night, thus permitting the water to be drained out without wasting oil. Draining the delivery valve chest will also drain the delivery pipe up to the check valve if those pipes are above the chest and without water seals in them. If this pipe is arranged below the pump, then separate drain cocks should be provided and should be placed at the lowest positions in the piping.
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When a pump fails to start after standing for some time it should be primed by filling the barrel with water and starting the pump slowly. If after priming it fails to raise water, the suction pipe should be examined and also the plungers and the valves. If the plunger packing has become dry and hard, merely filling the water end with water will not at once remedy the trouble because the packing must be thoroughly soaked before it will work properly.
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Pumps should be packed with the same care and consideration as is used with the best steam engines. The rods should be packed just tight enough to prevent leakage, and the packing renewed often enough to keep it soft and pliable, in which state it readily absorbs oil. Old packing will upon examination be frequently found full of sand and small particles of grit.
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Metallic packings are now extensively used on steam piston rods and upon the rods of air pumps.
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