45. Q. How is the fire affected by and what causes clinkers?

A. A clinker shuts off area of grate surface according to its size, and

thereby shutting off that much of the air supply and interfering with

proper combustion. Clinkers are caused by firing too heavy in spots,

which prevents sufficient air passing up through these spots and allows

the coal to run together, melting the ash, and sand; running a hoe or

slash bar through the fire will bring the points of melted sand

together, thereby causing a clinker.