Why Does Your Boiler Need A Circulating Pump?
If your home uses hydronic heat, you rely on a boiler to provide hot water to your radiators, baseboards, or other heating elements. Most modern homes use hot water boilers instead of steam boilers. Despite the name, these appliances heat water to sub-boiling levels. In other words, a central heating boiler is usually more like a water heater.
Unlike steam boilers, hot water boilers can't rely on gravity to do the hard work.