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Plumbing TermExpansion Tank
/ik-span-shuhn tank/
A tank that absorbs pressure buildup from heated water to protect your plumbing system.
Full Definition
A small pressurized tank connected to a water heater that absorbs excess pressure caused by thermal expansion when water heats up.
Common Usage
“Required by code in most areas with closed water systems, expansion tanks prevent pressure relief valve leaks and premature water heater failure.”
Did You Know?
Without an expansion tank, the pressure from heating water has nowhere to go in a closed system, potentially causing your water heater's relief valve to constantly drip or even fail catastrophically.