air shutter An adjustable shutter attached to the primary air openings of a burner used to control the amount of primary air entering the burner.
aldehyde A class of compounds that can be produced from incomplete combustion of gas fuels.
allen wrench An L-shaped tool that is used to remove hex screws.
alternating current (AC) Electrical current that flows in one direction and then reverses itself and flows in the opposite direction. In 60-cycle current, the direction of flow reverses every 120th second.
ambient temperature Temperature of air that surrounds an object on all sides.
ammeter A test instrument used to measure current.
ampere The number of electrons passing a given point in one second.
armature The section ...