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Home > Tank Styles > Compression Tanks

Compression Tanks

The compression tank has been used for many years, and in some systems has worked very well. Using a plain steel expansion tank makes the systems an air control system. One must control the air volume or air cushion above the water level in the tank. The common face between this air cushion and the water in the tank allows the air to be absorbed by the water. If the air is not removed properly from the water and placed back into the air cushion, the compression tank will become waterlogged.

Compression tanks are designed to absorb the expansion forces and control the pressure in heating/cooling systems.

  • Plain steel tanks have a common interface between the liquid, water, in them and the air. This interface allows the air to be reabsorbed by the water and thus must be controlled by use of air separation devices.

  • Plain steel tanks must be installed above the air separation device to enable the separated air free passage back into the tank. The size and total tank and water weight must be considered during construction.

  • Plain steel tanks are installed in the system with air at atmospheric pressure. This air will be compressed by water as the system is filled and brought up to minimum operation pressure or fill valve pressure. This filling action will fill the tank approximately 50% full or more before the system is put in operation. This increases the size of the tank and adds to the total weight.

Compression Tank Models

NA Compression Tanks (ASME)

The NA Series Compression tanks are ASME plain carbon steel expansion tanks. They are designed to absorb the expansion forces and control the pressure in heating / cooling systems.

NA Sizes and Specifications

NA Submittal

Stainless Steel Model Available


NAG Compression Tanks (ASME)

The NAG Series Compression tanks are ASME plain carbon steel expansion tanks. They are designed to absorb the expansion forces and control the pressure in heating / cooling systems.

Please consult the factory for information regarding this model.


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