Fixtures & Water HeatersQuestion 185 of 360
Thermal expansion in a domestic hot water system is primarily caused by:
a.water hammer from fast-closing valves
b.air trapped in the piping
c.corrosion inside the tank
d.water increasing in volume as it is heated
Explanation
Water expands in volume as it is heated, and in a closed system that added volume has nowhere to go, raising system pressure. This is thermal expansion. An expansion tank absorbs the increase to protect fixtures, the tank, and the relief valve.
Law Reference: 2022 California Plumbing Code (CPC) §608.3Practice all 360 questions free — no signup required.
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