Hydronic heating systems where water or steam, carries the heat through pipes to areas to be heated. In hydronic system water is heated in a boiler and circulated through pipes to a heat transfer component such as radiator, or finned tube baseboard units, convector, radiant infloor tubing. Here heat is given off to the air in the room, the water is then returned to the boiler. These systems are designed to have one or more zones, there may be several zones, such as lower level and main level, and bedroom. Zoning allows the system to have different temperature through out the dwelling. A boiler is in its simplest form a furnace that heats water to the desire water temperature for the heat transfer component. Due to the popularity of radiant infloor heating there are a large variety of boilers to select from with oil, gas, electric, wood, pellet fired boiler as the heat source. With a modulating firing rate and temperature ranging to include efficiency technology.

It is important to eliminate air from hydronic heating system for several reasons, air can cause a significant amount of corrosion, it can cause blockage of the water circulation system. And produce an undesirable noise and decease the efficiency to the system. It is recommended to inject anti freeze into a hydronic heating system in the event that the boiler mis-fired with no one monitoring the dwelling, or when piping is installed to exposed cold temperatures. There are others additives that will lubricate, remove sludge and corrosion scale. These system can and will provide years of service free operation with a preventive maintenance plan.