Waste fuel - Any by-product fuel that is waste from a manufacturing process.
Waste heat - Sensible heat in non-combustible gases.
Water column - A vertical tubular member connected at its top and bottom to the steam and water space respectively to a boiler, to which the water gage, gage cocks, high and low water alarms and fuel cutoff may be connected.
Water gage - The gage glass and its fittings for attachment.
Water hammer - A sudden increase in pressure of water due to an instantaneous conversion or momentum to pressure.
Water level - The elevation of the surface of the water in a boiler.
Water tube - A tube in a boiler having the water and steam on the inside and heat applied to the outside.
Water vapor - A synonym for steam, usually used to denote steam of absolute low pressure.
Weep - A term usually applied to a minute leak in a boiler joint which forms droplets (or tears) of water very slowly.
Wet back - Baffle provided in a firetube boiler joining the furnace to the second pass to direct the products of combustion that is completely water-cooled.
Wet steam - Steam containing moisture.
Windbox - A chamber below the grate or surrounding a burner, thru which air under pressure is supplied for combustion of the fuel.
Windbox pressure - The static pressure in the windbox of a burner or stoker.
Zero governor - A regulating device that is normally adjusted to deliver gas at atmospheric pressure within its flow rating.
