Wet lay-up fills the boiler completely with treated water, high in pH and oxygen scavenger, sometimes with a nitrogen blanket, so no air pocket remains. Dry lay-up drains, cleans and dries the boiler, then seals it with trays of desiccant inside. A heating boiler left half full and open all summer can corrode more in those months than in a whole heating season.
Number one's down till October, put it in wet lay-up with the extra sulfite and check the residual every week.
Also heard as
- layup
Related terms
Oxygen pitting
Deep localized corrosion pits in boiler steel caused by dissolved oxygen in the water.
Oxygen scavenger
A chemical fed to boiler feedwater that reacts with and removes the last traces of dissolved oxygen.
Fireside
The surfaces of a boiler exposed to flame and combustion gases, as opposed to the waterside surfaces in contact with water.