Circulator pumps move liquids through a closed circuit. They consist of a motor, impeller and seal within a metal casing that is connected by pipe flanges to the rest of the hydronic system.*
Hot water recirculating pumps are used to maintain a constant temperature at the point-of-use fixture.
There are several factors to consider when purchasing a circulator pump including construction material, connection method, horsepower, size and special features.
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Construction Material
In residential closed loop heating applications circulator pumps are usually made of cast iron. Stainless steel and bronze circulators are typically used in domestic hot water recirculation applications because they are lead-free.
Connection Method
Residential circulators are commonly connected to supply piping with flanges ranging in size from ¾” to 1-1/2”. As a rule, flange materials should match the material of the pump being used. Circulators can also be connected using sweat and threaded connections. These are frequently found in plumbing applications.
Size
A perfectly-sized circulator will accommodate a system’s flow rate demands while overcoming it’s pressure loss. Consult manufacturer pump curves to size a pump according to flow rate (x-axis) and head loss (y-axis).
Fittings, check valves, mixing valves, balancing valves, heat exchangers, tubing and other flow-impacting elements should also be taken into account when sizing a circulator pump.
Pump Products application engineers are standing by to provide technical assistance.
Horsepower
A circulator pump’s horsepower (HP), or motor strength, directly affects it’s flow rate and head loss performance. Horsepower must be considered in connection with RPMs when choosing a pump based on the GPM and head loss demands of your system. Our application engineers are available to provide technical assistance.
Special Features
Integral flow check is a popular feature insuring that a check valve will not be needed elsewhere in the system. Variable speed features available in some models make it possible to fine tune the operation of a circulator to enhance performance and conserve resources. Consider these and other features when selecting a circulator pump.
*Large commercial circulators often have exterior motors and are pad-mounted.
Pump product application engineers are standing by to provide technical assistance, price quotes or to answer any questions you may have regarding residential and commercial circulating pumps by leading manufacturers including Armstrong, Bell & Gossett, Taco, Grundfos, and Wilo. Call our Toll Free Number 1-800-429-0800.
