Expansion Tanks

Expansion Tanks for Water Heaters and Hydronic Systems

Shop expansion tanks built to protect closed plumbing and heating systems from pressure spikes. We stock thermal expansion tanks for potable water and water heater expansion tanks (often 150 PSIG rated), plus hydronic expansion tanks for boilers and heating loops (up to 240°F), in sizes from 2.1 to 159 gallons.

Choose trusted brands like Amtrol (inventor of the Therm-X-Trol), Flextron, and Zilmet, along with expansion tank brackets for clean, secure installs. A properly sized tank helps prevent T&P valve discharge, pipe damage, and warranty issues; a quick rule of thumb is about 10% of the water heater volume, with pre-charge set to match incoming pressure.

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Pair your tank with residential water heaters or indirect water heaters

Get contractor-ready pricing, BBB A+ service, 90-day returns, free shipping on most orders over $99, and delivery in less than 24 hours. Need sizing help? Call 844-669-4330 (9am–5pm EST).