Fixtures & Water HeatersQuestion 184 of 360
A house has a water meter with a check valve installed on the service. What must be added at the water heater to control thermal expansion?
a.A second T&P valve
b.A larger cold water pipe
c.An expansion tank or approved expansion control device
d.A pressure-reducing valve on the hot side
Explanation
When a check valve, backflow preventer, or pressure-reducing valve creates a closed system, heated water cannot expand back into the main and pressure spikes. An expansion tank or listed expansion control device must be installed to absorb that thermal expansion. Without it, the relief valve may weep or the tank may be stressed.
Law Reference: 2022 California Plumbing Code (CPC) §608.3Practice all 360 questions free — no signup required.
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