164 STEAM BOILERS 



thus shutting down under a reduced pressure with only a remote 

 possibility of its rising again through the night. If the fires 

 are properly banked and the steam worked off while the feed 

 is on, it will be remotely possible for the pressure to rise during 

 the night to a dangerous extent. To bank the fires they should 

 be shoved to the back of the grate and well covered with 

 green fuel, leaving the front part of the grate bare, thus pre- 

 venting any possibility that the banked fire will burn up through 

 the night. 



Closing Valves and Damper. The steam stop-valve, feed 

 stop-valve, whistle valve, and other steam valves should be 

 closed ; the valves at the top and bottom of the gauge glass also 

 should be shut off to prevent loss of water, etc. in case the glass 

 should break during the night. If there is a damper regulator, 

 it should be so arranged that the damper may be left closed, 

 but not quite tight, because a small opening must be left to 

 permit the collecting gases from the banked fire to escape up 

 the chimney; otherwise there is danger that the accumulated 

 gas will ignite and cause an explosion. It is very important 

 to take this precaution and also to make a mark by means of 

 which the distance the damper is open can be ascertained at a 

 glance. In fact, a damper should be so made that when shut 

 to the full extent of its travel there will be still sufficient space 

 around it to allow the gas to escape. The damper regulator 

 should be rendered positively inoperative in any manner per- 

 mitted by its design so that the damper when closed will remain 

 in that position until connected properly by the attendant 

 in the morning. 



Starting the Fires. On entering the boiler room in the morn- 

 ing, the quantity of water in the boiler should first be noted. 

 The gauge glass and the gauge-cocks should be tried and the 

 water level determined. After it has been found that the 

 water is not too low, the banked fires may be pulled down and 

 spread over the grates and allowed to burn up slowly, the 

 damper regulator, if one is fitted, in the meantime having been 

 connected. 



Blowing Down. While the fires are burning and before the 

 pressure begins to rise, the blow-off cock or valve should be 

 opened and the boiler blown down; that is, a small quantity of 



