boiler [2]
Device in which water is heated before being distributed to the radiators.
Aquastat 
Device regulating the water temperature.
pressure relief valve 
Mechanism for releasing pressure by letting off excess water or steam.
box 
Rigid metal casing for the boiler.
chimney 
Channel through which combustion gases are evacuated.
burner 
Device for mixing a flammable substance with air, and fanning and igniting this mixture in a boiler’s fire pot.
heat exchanger 
Set of pipes transferring the heat produced by combustion to the water.
heating element 
Conduit in which the water is heated.
air tube 
Cylindrical part covering the nozzle and the ignition electrodes; it joins the burner to the fire pot.
fire pot 
Part of the boiler where the combustion of air and heating oil takes place after they pass through the burner.
draft hole 
Peephole for viewing the inside of the fire pot.
insulation 
Material covering the sides of the boiler to reduce heat loss.