A water failure switch stops the compressor in the event of failure of the cooling water supply for the condenser. This is a pressure-actuated switch. It is generally similar to the low-pressure cutout switch and the high-pressure cutout switch previously described. If the water failure cutout switch fails to function, the refrigerant pressure in the condenser will quickly build up to the

Figure 16-16.-Pressure-actuated control switch.

point that the high-pressure switch stops the compressor.

Figure 16-16 illustrates the general type of pressure-actuated control switch that is used in most installations. (In the illustration, the cover to the switch has been removed.) These switches are designed to operate at various pressure ranges. Some switches have manual reset buttons to prevent automatic restoration of power after the event of a high-pressure shutdown, such as high compressor discharge pressure. The oil pressure failure switch we discussed earlier has two bellows instead of one as shown in figure 16-16.