Figure 4-58. - Cast-iron boiler castings.

Figure 4-59. - Cutaway view of a cast-iron boiler.

STEEL HOT-WATER BOILERS

Most steel hot-water boilers are constructed in two sections. One section consists of the water jackets, combustion chamber, and smoke passages. These components are either welded or riveted together as a unit. The other section consists of the base and either the grates or burner and is constructed according to the type of fuel used (fig. 4-60).

Another steel boiler is a horizontal unit of the portable type, having an internal firebox surrounded by water lanes. It rests either on a cast-iron or a brick base. The front part of the boiler rests on a pedestal. A disadvantage of this one-piece steel boiler is that it is heavy and requires special equipment to lift it.

INSTALLING BOILERS FOR HOT-WATERHEATING

A boiler must have a good foundation. The top surface of the foundation should be level to ensure