Function

• Generally, the way forced hot water heating systems work is that when the thermostat senses a drop below the set temperature, the system kicks on. The water heats and then expands (from the heating process) and ultimately flows into a tank, where the air is compressed. The hot air is then directed to baseboard or radiators in rooms to heat the home.
  
  

Considerations

• Electricity, oil or gas can fuel a forced hot water heating system. Maintenance is needed to keep the system working properly, such as keeping the pumps oiled, dusting the equipment, draining the tanks periodically and bleeding the trapped air from the system.
  
  

Identification

• A forced hot water heating system includes a boiler, an expansion tank typically found above the boiler that is connected through piping, and controls such as a pressure relief valve, pressure gauge and a pressure reducing valve. Also the forced hot water system typically contains a circulating pump, and controls and piping.