POULTRY LABORATORY GUIDE 113 



Before starting a fire make sure that the sys- 

 tem is filled with water so that it shows on the 

 bottom part of the glass in the expansion tank ; 

 if not full, allow water to flow into same until it 

 is full, being sure to open valves and pet cocks 

 in the highest part of each coil to let out air 

 which will gather there. 



Start a good wood fire, and get it well imder 

 way before putting on any coal. To cause the 

 heater to burn freely open the pipe damper, 

 shut the door to the fire box, and open the lower 

 ash pit door. When a good bed of coals is ob- 

 tained and the water is at the desired tempera- 

 ture, it may be checked from rising higher by 

 partly closing the pipe damper, shutting or partly 

 shutting the bottom door, and leaving the upper 

 door ajar. The exact position to leave each 

 door and damper will have to be determined by 

 practice, and will vary as regards height and size 

 of chinmey ; also it wiU vary greatly every day 

 as regards .temperature, wind velocity, etc. 

 When it is desired to cause more heat to be radi- 

 ated into the house, it is necessary to heat the 

 water in the boiler to a higher temperature, and 

 this can be accomplished by opening the pipe 

 damper, also the lower door, and closing the door 

 to the fire box. If it is desired to cool the water, 

 the reverse is the rule. 



