Circulating Pumps (Circulators)

In forced-hot-water heating systems, circulating pumps (also some­times called circulators or booster pumps) are used to force the hot water through the piping or tubing. Figure 7-29 illustrates a typical location of one of these pumps on a return line. The operation of


Circulating Pumps (Circulators)

Figure 7-29 Circulating pump is located on the return water line next to the boiler.

The one or more circulating pumps in a hydronic system is con­trolled by a circulator relay.

Circulating pumps for hot-water heating systems are designed and built to handle a wide range of pumping capacities. They will vary in size from small booster pumps with a 5-gpm capacity to those capable of handling thousands of gallons per minute. Some are field serviceable with replaceable cartridges.

In order to select a suitable pump for a hot-water heating sys­tem (i. e., one that will produce maximum flow without overload­ing the pump motor), it is necessary to match the operating characteristics of the pump correctly to the requirements of the heating system.

The correct location of a pump is crucial to its successful opera­tion. Pump manufacturers will usually give detailed information in their literature on this point. Circulating pumps with mechanical seals are very common in hot-water heating systems.

Posted in Audel HVAC Fundamentals Volume 1 Heating Systems, Furnaces, and Boilers