60 ROUGH-AND-TUMBLE ENGINEERING 



to blow off at 115 pounds leave it there. Don't screw 

 it down every time you want more power, for if you do 

 you will soon have it up to 125 pounds, and then if you 

 want more steam at some other time you will find your- 

 self screwing it down again, and what was really in- 

 tended for a safety valve loses all its virtue as a safety, 

 as far as you and those around you are concerned. If 

 you know you have a good boiler you are safe in setting 

 it at 125 pounds, provided you are careful to not set it 

 up to any higher pressure. But my advice to you is 

 that if your engine won't do the work required of it at 

 115 pounds, you had best do what you can with it until 

 you can get a larger one. 



A safety valve is exactly what its name implies, and 

 there should be a heavy penalty for anyone taking that 

 power away from it. 



If you refuse to set your safety down at any time, it 

 does not imply that you are afraid of your boiler, but 

 rather you understand your business and realize your re- 

 sponsibility. 



I stated before what you should do with the safety 

 valve in starting a new engine. You should also exam- 

 ine it and test it every few days. See that it does not 

 become slow to work. You should note the pressure 

 every time it blows off. You know where it ought to 

 blow off, so don't allow it to stick or hold the steam be- 



