A. Yes; if the pressure is not regularly maintained, the fluctuations of
temperature cause constant contraction and expansion to take place. If
the fire is not carried level, but is carried heavy in some parts of the
fire-box and light in others, holes will be worked in, cold air drawn
through, lowering the temperature, chilling the tubes and causing leaks.
Carrying the fire too heavy in some places, causes clinkers to form. If
the door is open too long, too much cold air is drawn over the fire,
causing the tubes to leak.