126 STEAM BOILERS 



1. Choked Suction Pipe or Strainer. If the suction pipe or 

 the strainer is partly choked, the injector, in either case, will 

 be prevented from lifting sufficient water to condense all the 

 steam issuing from the steam valve. The uncondensed steam, 

 therefore, will gradually decrease the vacuum in the combining 

 tube until it is reduced so much that the injector will not work. 

 The remedy in case the supply valve is partly closed is to open 

 it. In the case of a choked suction pipe, the obstruction should 

 be blown out. 



2. Suction Pipe Leaking. The leak may not be sufficient 

 entirely to prevent the injector from lifting water, but the 

 quantity lifted may be insufficient to condense all the steam, 

 which, therefore, destroys the vacuum in the combining tube. 

 A slight leak may exist that will simply cut down the capacity 

 of the injector. In such a case an automatic injector will 

 work noisily, on account of the overflow valve seating and 

 unseating itself as the pressure in the combining tube varies, 

 due to the leak. 



3. Boiler Check-Valve Stuck Shut.U the boiler check-valve 

 is completely closed, the injector may or may not continue to 

 raise water and force it out of the overflow; this depends on 

 the design of the injector. If the boiler check is partly open, 

 the injector will force some of the water into the boiler and the 

 remainder out of the overflow. In case the check-valve cannot 

 be opened wide, water may be saved by throttling both steam 

 and water until the overflow diminishes, or, if possible, ceases. 

 The steam should be throttled at the valve in the boiler steam 

 connection. If a check-valve sticks, it can sometimes be made 

 to work again by tapping lightly on the cap or on the bottom 

 of the valve body. 



4. Obstruction in Delivery Tube. Any obstruction in the 

 delivery tube will cause a heavy waste of water from the over- 

 flow. To remedy this, the tube will have to be removed and 

 cleaned. 



5. Leaky Overflow Valve. A leaky overflow valve is indi- 

 cated by the boiler check chattering on its seat. To remedy this 

 defect, grind the valve on its seat until it forms a tight joint. 



6. Injector Choked \Vilk Lime. It is essential to the proper 

 working of an injector that the interior of the tubes be 



