Article Index

Waste heat- Sensible heat in non-combustible gases discharged to the environment.

Water alkalinity- amount of carbonates, bicarbonates, hydroxides and silicates or phosphates in the water and is reported as grains per gallon, or ppm as calcium carbonate.

Warping- Bending or distortion of boiler or superheater tubes, usually caused by overheating.

Water column- A vertical tubular member connected at its top and bottom to the steam and water space respectively of a boiler, to which the water gauge, water level controls, and fuel cutoff may be connected.

Water column blowdown valve- Valve on the bottom of the water column used to remove sludge and sediment that might collect at the bottom of the water column.

Water gauge- The gauge glass and its fittings for attachment.

Water hammer- A banging condition that is caused by steam and water mixing in a steam line.

Water level- The elevation of the surface of the water in a boiler

Water softening- The removal of scale-forming salts from water.

Watertube boiler- Boiler that has water in the tubes with heat and gases of combustion around the tubes.

Waterwall- Vertical or horizontal tubes found in the furnace area of water tube boilers that lengthen the life of the refractory.

Waterwall blowdown valve- Approved valve used to remove sludge and sediment from waterwalls and waterwall headers.

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 low absolute pressure.

Waterwall- The side of the boiler consisting of water-carrying tubes which absorb radiant heat that prevent excessively high furnace temperatures.

Weep- a small leak (opening) that allows water to drain from within a boiler joint which forms droplets (or tears) of water very slowly.

Wetback boiler- Firetube boiler design with the back portion of the boiler has a water jacket.

Wetness- A term used to designate the percentage of water in steam. Also used to describe the presence of a water film on heating surface interiors.

Wet steam- Steam containing moisture.

Windbox (plenum chamber)- Pressurized air chamber that supplies air to a furnace.