Your boiler heats your home during the winter to keep it warm and comfortable inside. The water in your boiler system is heated with the heat exchanger, a number of tubes in the firebox, which the water is pumped through. The tubes are cooper, steel, cast iron, or other alloys and they go through a lot of abuse to heat the water to warm your home. Over time they get clogged with soot and may not heat as well. Cleaning the soot from the heat exchangers in your boiler will correct the problem.
Turn off the boiler and wait for it to cool. Open the service door using the wrench or screwdriver.
Open the firebox to get at the heat exchangers, the tubes positioned over the firebox.
Vacuum the soot from the tubes with the brush attachment. Scrub any stuck-on soot from the heat exchangers with the brush. Wipe down the tubes with a wet cloth.
Close the firebox door and the service door. Turn the boiler back on.