When water heats up, it expands. The expanding water affects the pressure in closed heating systems, causing an increase in system pressure. Over time, this pressure continues to rise, creating fluctuations that can damage the system. If the expanding water is not controlled as the temperature rises, it can cause leaks in pipes, the boiler, and the heating system. These leaks, which occur at the weakest points, reduce system efficiency and can lead to system failure. The device designed to prevent this pressure and potential hazards is called an expansion tank. Essentially, the expansion tank acts as a “mediator” between the increased heat pressure and the heating system. It helps control the rising temperature, reduces and balances system pressure, and ensures the system operates at optimal performance. Nowadays, every boiler room includes an expansion tank. Expansion tanks equalize the pressure in the system. They are small tanks divided into two sections by a rubber diaphragm.
Here’s how the system works: when hot water enters the heating system, the system pressure increases. As this pressure rises, the diaphragm in the expansion tank is pushed downward, compressing the air in the tank and creating space for the excess water. This reduces excessive pressure in the system and prevents damage to the pipes.
What Is a Contraction Tank?
Contraction tanks are designed similarly to expansion tanks but are used in cooling systems. They operate on the opposite principle of heating systems. In heating systems, water expands when heated, increasing system pressure, which is then absorbed by the expansion tank. The tank holds water equal to the calculated expansion volume based on the maximum water temperature. When the system pressure balances with the tank pressure, the flow stops. When the system returns to normal pressure, the tank returns the water to the system. In cooling systems, water contracts as it cools, reducing system pressure. Because the contraction tank pressure is higher, it supplies water to the system until equilibrium is achieved, then returns it to the tank when the system stabilizes.
What Is a Balance Tank?
Another name for the expansion tank is a balance tank. It is used in water pressurization systems alongside booster pumps. It is called a balance tank because it helps balance the system pressure. Without a balance tank or if the tank is faulty, pressure fluctuations occur every time the pump operates. The balance tank helps reduce these fluctuations. Another function in booster pump systems is to prevent frequent pump cycling. The tank’s capacity is determined by the motor power and the maximum number of pump cycles per hour.
How to Calculate Expansion Tank Size
When selecting an expansion tank, several points must be considered:
- Tanks come in various sizes according to the pump system, ranging from 2 liters to 5,000 liters, and may be cylindrical, horizontal, vertical, or spherical.
- The tank must be suitable for the maximum liquid temperature. For potable water, a standard tank is sufficient.
- The installation height is important.
- Pay attention to the tank’s pressure resistance.
- For use in industrial kitchens, food production, high-humidity areas, or hygienic environments, stainless steel expansion tanks may be required.
Periodic Maintenance of Expansion Tanks
Maintenance is crucial. Common problems often result from air loss, so tanks should be checked every two months. Leakage is another common issue. If air is missing, water accumulates, and the tank eventually begins to leak. Problems usually arise from lack of maintenance. If the tank’s air is depleted, the membrane is punctured, or the tank itself is damaged, leakage occurs. Damaged tanks must be replaced, while air loss can be corrected by repressurizing. Pressurized tanks typically last 5 to 8 years.
Where Are Expansion Tanks Used?
Expansion tanks have a wide range of applications in both industrial and private sectors, including:
- Water systems
- Washing systems
- Pressure systems
- Irrigation pumps
- Solar and pressure maintenance systems
- Cooling systems (contraction tanks)
- Hot water and heating systems
Masdaf Expansion Tanks
Closed expansion tanks used in plumbing contain a hygienic, odorless BUTYL membrane for sanitary systems, and EPDM membranes for heating and cooling systems, with pressurized nitrogen gas around the membrane.
The outer surfaces of the tanks are coated with corrosion-resistant electrostatic powder paint. Tanks with replaceable membranes do not come in contact with water unless the membrane is damaged, so they are not corrosive. Under normal conditions (clean water and proper pump cycling), closed expansion tanks have a long service life.
Applications of Replaceable Membrane Closed Tanks:
- Single or double-pipe heating, air conditioning, and industrial systems
- Underfloor heating systems, primary filling circuits
- Boiler or storage filling circuits
Expansion Tank Prices
Expansion tank prices vary depending on installation height, pressure resistance, and tank size. Tanks are not sold at a single price as each has unique features. The location and purpose of use significantly influence the price.