Mechanicals · definition
A small tank absorbing thermal expansion on a closed system (with a backflow preventer/PRV). Code-required in many areas to protect the heater and plumbing.
Source: ASHRAE — Terminology: Expansion Tank
Where this term lands on a Columbus budget
The cost pages carry the current local ranges, and the guides explain what moves them. A published range becomes a project number only after someone looks at the site.