Boiler Circulator Pump - The boiler circulator pump induces the flow of hot water through the boiler and the boiler loop. Usually, the boiler circulator pump is controlled by the aquastat. However, there are various levels of control that can be found that control pumps. One way is by the aquastat as mentioned above. Another way is by an end switch in a zone valve. A thermostat in a particular zone will call for heat and the thermostat calls for the zone valve to open. When the zone valve is fully open an end switch closes the circuit to energize the circulator pump. Typically, the circuit is a control circuit so when the end switch closes it closes the circuit for a relay to energize the circulator pump
Boiler Circulator Pump - Proper Pump Sizing
It is important when the circulator pump is installed that the proper size of pump is selected for the amount of flow needed for the loop. Oversized pumps can cause issues with the flow and cause efficiency issues with the system. Too much velocity causes laminar flow issues which causes the loop not heat properly and the boiler to fire unnecessarily. It can be a big difference in fuel consumption. The circulator pump should be sized by an HVAC professional familiar with sizing circulator pumps.
Boiler Circulator Pump - Proper System Sizing and Installation
A properly sized pump in a properly sized loop will be efficient however if the pump is not sized properly you can waste money unnecessarily on wasted energy in both electricity for the pump use and energy for the boiler running. So in that case, it is necessary to hire a qualified contractor whether that contractor is a plumber or an HVAC company to install the components and the piping system. Otherwise you can waste a lot of money in unnecessary energy cost for an improperly installed system. That includes the circulator pump.
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Boiler Circulator Pump