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The Boiler Expansion Tank and Heating Repair

If you’ve ever taken a good look at your boiler, examined its various external parts and components, you probably noticed what looks like a smaller water tank above the boiler with a pressure gauge attached to it. That’s the expansion tank, and it’s a vital part of the boiler system that can prevent serious problems leading to repairs. The expansion tank itself can need repairs as well, and it’s important for the general health of your heating system that it remains in good working order.

In this post we’ll explain what the expansion tank is and how it helps prevent problems in your boiler. If you encounter any troubles related to an expansion tank, call Boehmer Heating & Cooling. We have live operators standing by 24/7 to help with your heating repair in Pittsburgh, PA.

The Basics of the Expansion Tank

Despite what the name may indicate, an expansion tank is not an extra water tank. The expansion tank does contain some water, but half of it contains air, which serves the purpose of relieving the pressure of the water in the main tank.

If you were to view an expansion tank in a cut-away view, you would see two separate compartments with a rubber diaphragm between them. One compartment connects to the top of the boiler tank, where rising hot water enters it. The other side contains pressurized air connected to the valve that measures the pressure level. This set-up allows for the water to press against the diaphragm when its pressure rises, pushing against the air cushion on the other side. This relaxes the pressure on the water in the tank.

To create equilibrium, the valve in the other compartment adds air. As the water pressure begins to drop, the pressure from the air eventually restores the balance between the two sides.

Older boilers did not have expansion tanks. Instead, to relive high water pressure, they maintained an air cushion within the top of tank itself. However, this promoted corrosion because of the presence of oxygen. The creation of the expansion tank permitted a release of pressure without allowing the mixing water and oxygen.

How the Expansion Tank Prevents Repairs

High water pressure can cause some serious problems. When pressure spikes, it threatens leaks throughout the system, and could even cause the boiler tank to rupture. Even small amounts of pressure will put extra stress on the system and wear it down. The expansion tank maintains an even pressure to prevent these occurrences.

Sometimes the expansion tank needs repairs: the membrane can rip or come loose, or the valve breaks. When high water pressure starts to affect your boiler, call for repairs right away to see if the expansion tank needs attention.

Boehmer Heating & Cooling has kept people warm since 1933 with our excellent heating repair in Pittsburgh, PA. Make us your first call when you need help with an expansion tank or any other part of your boiler.

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