A. Open the pet cock at the top of the syphon before taking the hose down.

59.  Q. Is any more water used when the engine foams than when the water is solid?

A. Yes, very much more.

60.  Q. How would you prevent injector feed pipes or tank hose from freezing in winter when not in use?

A. The steam valve should be slightly open to permit a slight circulation of steam through the feed and branch pipes.  The heater cock should be closed and the drip cock under the boiler check or on the branch pipe should be opened to insure a circulation of steam through the branch pipe.

61.  Q. How would you prevent the overflow pipe from freezing with a lifting injector?

A. The overflow valve should be opened just enough to permit a little steam to escape through the overflow pipe to prevent it from freezing.

62.  Q. Name the various parts of the injector.

A. The injector consists of a body supplied with a steam valve, a steam nozzle, a primer, a combining tube, a delivery tube, a line check valve, an overflow valve, a water valve, and a lifting injector has a lifting tube.

63.  Q. What may be done if a combining tube is obstructed?

A. The steam valve bonnet may be removed and the obstruction forced out with a piece of stiff wire, or uncouple the delivery pipe from the injector and unscrew and remove the tubes; the obstruction can then be removed and the tubes replaced.

64.  Q. How is the greatest injury done to a boiler when cleaning or knocking the fire?

A. By excessive use of the blower drawing cold air through the fire-box and flues.

65.  Q. Why does putting a large quantity of cold water into a boiler when the throttle is closed cause the flues to leak?  When is this most serious?

A. When steam is not being used there is not much circulation of water in the boiler, and the water entering the boiler at about 150 degrees temperature is heavier than the water in the boiler.  The cooler water will go to the bottom and reduce the temperature in that part of the boiler and causing the flues to contract in length as well as in diameter and this has a tendency to pull them out of the sheet.  This will loosen them and cause them to leak.  After the fire has been knocked this tendency is much greater, and for that reason cold water should not be put into a boiler after the fire has been knocked out.  Always fill the boiler before the fire is knocked out.

66.  Q. Is warm water in the tank of any advantage in making steam rapidly?

A. Yes; careful experiments have shown that a locomotive will generate one per cent. more steam for every eleven degrees that the tank water is heated; thus by heating the feed water in the tank from 39 degrees to 94 would effect a saving of five per cent.

67.  Q. Then why not heat the feed water to the boiling point (212 degrees)?