Bladder Expansion Tanks

Bladder expansion tanks have a totally replaceable bladder and are often referred to as replaceable diaphragm tanks. This tank must be equipped with large service openings that allow the bladder to be replaced without having to remove the tank from its mounting.

Bladder tanks are required in a closed loop heating or chilled water HVAC system to absorb the expanding fluid and limit the pressure within a heating or cooling system. A properly sized tank will accommodate the expansion of the system fluid during the heating or cooling cycle without allowing the system to exceed critical pressure limits.

The expansion tank uses compressed air to maintain system pressures by accepting and expelling the changing volume of water as it heats and cools. Some tank designs incorporate a diaphragm or bladder to isolate the expanded water from the pressure controlling air cushion, which is pre-charged at the factory and can be adjusted in the field to meet critical system requirements. This design and operation of this style of expansion tank allows the designer/specifying engineer to reduce tank sizes up to 80%.

Were you looking for a non-replaceable bladder tank?


NLA Series (ASME)

The NLA are the industries broadest line of bladder style tanks. NLA Expansion Bladder Tanks:

  • ASME certified
  • Heavy-duty replaceable butyl bladder
  • Sizes range from 10 to 4,000 gallons
  • Working pressures of 125 psi (std), 200 and 250 psi

NLA 35-800L

NLA 35-800L HP (High Pressure)

NLA 1000-15000

NLA 1000-15000 HP (High Pressure)


NLAP Series (ASME)

NLAP Expansion Bladder Tanks:


NL Series (Non-ASME)

NL Expansion Bladder Tanks: