In an oil fired hydronic heating system the source of fuel is oil or an oil blend. In this system, the oil pot is lined with a refractory substance and the oil is stored in a tank near the system or outside. The oil is kept under constant pressure.
The refractory substance is often made of stainless steel, cast-iron or brick. There may also be linings of ceramic felts. These substances are necessary in oil fired hydronic systems because the flame temperature is so high. The flame would destroy the heat exchanger because the metal from which is is made could not withstand the high temperature. The refractory controls and redirects the high heat flame coming from the horizontally installed gun that throws the flame.
This system contains a high-voltage transformer and a spark arks its way across the spark gap at the burner nozzle. The spark causes a combustion and a flame starts. For safety, a “stat” is inserted to know the temperature of the gases that are created as a result of this combustion. It will send a signal to the pump to stop its action if it detects the gases are not burning.
The heat that is created is conducted through the wall of the boiler and into the water. The exhaust gases travel out the chimney and a draft will control pressure ratings. This is all controlled by a thermostat that calls for the combustion to happen and the heat to be transferred through the sytem and ultimately to the space being heated by radiators. The boiler water temperature is determined and regulated by a temperature and pressure sensing element. The element and the thermostat regulate the entire system through electric frequency.
There is also a high limit control in this system. It will turn the flow of oil off if temperatures reach dangerous levels. In addition, a pressure release valve helps regulate internal pressure. This system also contains an expansion tank that allows for the expansion and contracting of water.
Efficiency of Oil Fired Systems
Oil furnaces are efficient providers of heat. The Department of Energy has determined that oil fired hydronic heating systems obtain an annual fuel utilization efficiency of 83%.
Add to this the continued use of oil blends and biofuels and you can see how this is a good choice for heat in your home. The oils used today produce less toxic fumes, smoke, and soot than previous versions of oil. Oils that are derived from plant sources or from ethanol are also a good choice for this type heating system.