This  may  be  due  to  oversight  or  its  handle  may  be  so  placed
by  mistake  that  the  tank  valve  is  closed  when  it  is  supposed  to
be  open.  The  obvious  remedy  is  to  open  the  tank  valve  or  put  mi
the  handle  properly.
3.  Too  much  or  too  Utte  water  being  supplied  to  the  in-
jector for  the  prevailing  pressure.
In  case  of  too  much  water,  the  same  issues  from  the  overflow
only  slightly  warm,  and  the  remedy  is  to  reduce  the  supply  by
means  of  the  water  valve  until  the  injector  works  properly  arid
with  dry  overflow.  In  case  of  too  little  water,  the  same  issues
from  the  overflow^  at  a  high  temperature  mixed  with  vapor.
The  remedy  is  to  increase  the  supply  of  water  or  cut  down  the
supply  or  steam  until  the  injector  works  properly.
4.  The  delivery  noszle  of  the  injector  is  cut,  worn  or  ob-
structed.
In  event  of  the  first  two  defects,  replacement  is  the  only  rem-
edy. The  obstruction  in  this  or  in  any  other  of  the  nozzles  may
be  removed  by  taking  out  the  steam  valve,  then  inserting  a  piece
of  iron  through  the  nozzles  to  break  up  the  obstruction.  If  this
cannot  be  accomplished,  removal  of  the  nozzles  is  necessary.
Quite  frequently  it  is  found  that  a  piece  of  coal  or  waste  from
the  tank,  or  scale  from  the  pipes,  is  carried  into  the  nozzles,
obstructing  the  passages  just  sufficiently  to  prevent  the  water

84


524  THE  LOCOMOTIVE  UP  TO  DATE

from  readily  passing  through.  For  this  reason  it  is  necessary
that  pipes,  particularly  steam  pipes,  be  thoroughly  blown  out
before  they  are  connected  up,  and  that  the  tank  be  kept  clean.
5.  Leaks  in  the  Suction  Pipe.
