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Armstrong Expansion Tanks

Armstrong Expansion Tanks

An expansion tank absorbs the increase in water volume as a closed heating or cooling system warms up, keeping system pressure within limits. Without one, pressure rises until the relief valve opens – wasting water and treatment chemicals and drawing in fresh, oxygen-rich make-up water that causes corrosion.

Armstrong offers diaphragm, bladder and plain steel expansion tanks for hydronic heating and cooling, plus potable water and domestic hot water tanks, in ASME and non-ASME construction.

Which type do I need?

  • Diaphragm tanks (AX, AX-V, non-ASME) – a fixed diaphragm separates water and air; compact and economical.
  • Bladder tanks (L Series, WX-L) – water is held inside a replaceable butyl bladder, so it never touches the steel shell.
  • Potable and domestic hot water (WX-L, AST) – materials suitable for drinking water, NSF 61.
  • Plain steel tanks (AET) – traditional compression tanks, including high-temperature systems up to 450°F.
  • High pressure (AX-V 175/250 PSI, L Series High Pressure) – for tall buildings and high-pressure systems.

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Warranty

Covered by the Armstrong Fluid Technology manufacturer's warranty.

Need help sizing?

Send us the system volume, fill pressure, relief valve setting and operating temperatures and we'll recommend the right tank – call (416) 236-2338 or email sales@bramhambros.com.