Every gallon of makeup brings in dissolved oxygen, hardness and minerals, so steam plants soften, deaerate and treat it, and they meter it to catch losses. In a closed hot water heating loop, makeup should be close to zero; an automatic fill valve that keeps adding water hides leaks and feeds oxygen that corrodes the system from inside.
Makeup meter shows 300 gallons a day on a closed loop, that's a leak, find it before the boiler fills itself with rust.
Also heard as
- make-up water
- makeup
Related terms
Feedwater
The water pumped into a steam boiler to replace the water boiled off, a blend of condensate and treated makeup.
Condensate return
The piping and equipment that bring condensed steam back to the boiler room for reuse as feedwater.
Water softener
An ion exchange unit that removes calcium and magnesium hardness from makeup water by swapping them for sodium.
Oxygen pitting
Deep localized corrosion pits in boiler steel caused by dissolved oxygen in the water.