Everything You Wanted To Know About Your Boiler

What are your boilers main parts? What function do they serve?

The water boiler is a vessel that circulates heated water (the medium) to a heat exchanger such as a upright stand alone cast iron radiator, baseboard cast iron radiator (low profile), copper fin tube radiator, in floor or wall surface exchanger as well as a coil with a blower motor that blows the heated air in a space.

Water Boiler Components:

Lets start with the Pressure Reducing Valve.  This valve reduces the water pressure from your home or business which is supplied to you from your municipality (between 30 to 45 pounds of pressure down to 12 pounds of pressure which the water boiler is designed to operate at.

This is where the altimeter or pressure gauge comes into play.  The pressure gauge tells us much about how the water boiler is operating and at what pressure.  The next part is the air eliminator or air scoop.  The air eliminator’s sole purpose is to remove air that is created during normal operation of the water boiler as well as during troublesome times.
Water boilers and air don’t play well together.  Many service calls have to do with air in the system.  When you look at your water boiler system, you will see odd looking valves on the radiators on the upper portion of the radiators.  Those are air bleeder valves to remove air from your system (it is always best to bleed your radiators with the boiler off).  Next, there is the expansion tank.  The expansion tank does just that – it allows expansion of water by way of air.  As the water is heated, you will get some expansion.  The next item is the flow control valve.  This allows the flow of water in one direction right off the boiler vessel. The chimney is self explanatory (flue gas goes up the chimney and out the home or business).  However, the vent damper that may be on your chimney system near the top of the boiler serves to retain heat in the block of the boiler where the flue passages are to increase efficiencies by retaining more heat after the boiler stops firing or when the burners go off.  Most water boilers today have circulation pumps.  The circulation pump helps circulate the heated water through the radiators or your heat exchange source.  The last component that comes into play is the aquastat.  The aquastat controls the temperature of the water, turns on the circulation pump, and supplies 24 volts to the thermostat.  If the aquastat fails, the boiler will not turn on.

These are basic usages for your standard water boiler and its components.