26 SCIENCE OF SUCCESSFUL THRESHING 



time, these holes are liable to have become stopped with 

 rust. Before replacing the steam chest, see that the pack- 

 ing is in good order. 5. If the pump has been in use 

 some time, or has not been sufficiently oiled, the valve may 

 have become worn and leaky. This is not so likely to oc- 

 cur on the "C" size, as on the smaller pumps. When it 

 does happen, the remedy is a new valve and steam chest. 



When the Pump will not Lift Water. If the pump 

 runs all right when steam is turned on, but will not "pick 

 up" water, opening the drain cock in the boiler feed pipe 

 will relieve the pressure on the discharge valves, i. See 

 that the suction hose and its connections are free from leaks 

 and that the screen is not covered with rags, waste, leaves 

 or the like. If this hose has been in use for some time, see 

 that it is sufficiently firm not to collapse or flatten, and that 

 its rubber lining has not become loosened so as to choke 

 or stop the water supply. 2. Remove the air chamber 

 and look for dirt under the water valves. 3. If the pump 

 has been in use for a time the water-piston packing may 

 leak. Where dirty water is used, this packing must be 

 frequently renewed. Directions for re-packing are given 

 below. 



When the Pump almost stops after lifting water, the 

 trouble is in the delivery or feed pipe. This may be proved 

 by opening the cock in this pipe which will relieve the pres- 

 sure and allow the pump to run faster. Possibly the angle 

 valve near the boiler has been left closed. The check valve 



