174 CREAMERY BUTTER MAKING 



15. Never open or close valves when the water is too 

 low in the boiler, but immediately bank the fire with ashes 

 or earth. Opening the safety valve at such a time will 

 throw the water from the heated surfaces, resulting in 

 overheating and possibly in explosions. 



1 6. Use the poker as little as possible in firing. 



17. Keep the grate bars free from "clinkers." 



18. When the steam pressure goes too high, start the 

 pump, open the doors of the furnace and close the ash 

 pit. 



19. A steady and even fire saves fuel. 



GENERAL CARE OF BOILER. 



1. Always close the steam and water valves of the 

 glass gauge when you leave the building for half an 

 hour or more. 



2. Water gauges should frequently be blown out and 

 cleaned. 



3. Keep the exterior of the boiler dry. Moisture will 

 corrode and weaken it. 



4. The boiler should be blown off under low pressure 

 every two or three days. 



5. A boiler that is not used for some time should be 

 emptied and dried. If this cannot readily be done, fill 

 it full of water to which a little soda has been added. 



6. Frequently examine the safety valve to see that it 

 is in good working order. 



7. Do not empty boiler while brick work is very hot. 



8. Never pump cold water into a hot boiler. Leaks 

 and explosions may be the result. 



9. Leaky gauges, cocks, valves, and flues should be 

 repaired at once. 



