Heating and circulating pumps are used to maintain the desired flow rate of steam or hot water in a heating system.
The two types of pumps used in steam heating systems are (1) condensate pumps and (2) vacuum heating pumps. The condensate pump is used in a gravity steam heating system to return the condensation to low- or medium-pressure boilers. Vacuum heating pumps are used in either return-line or variable-vacuum heating systems to return condensation to the boiler and to produce a vacuum in the system by removing air and vapor along with the condensation.
Circulators are used in hot-water (hydronic) heating systems to maintain a continuous flow of the water in the system. They are smaller in size than either a condensate or a vacuum pump and are usually of the motor-driven centrifugal type.
