An expansion tank or expansion vessel is a small tank used to protect closed water heating systems and domestic hot water systems from excessive pressure. The tank is partially filled with air, whose compressibility cushions shock caused by water hammer and absorbs excess water pressure caused by thermal expansion.

What is the purpose of an expansion tank?

Its purpose is to deal with thermal expansion of water as it heats up in the water heater - to prevent water pressure from getting too high. If water pressure gets high enough it can damage valves in plumbing fixtures, joints in supply pipes and even the water heater.

Is an expansion tank necessary?

When is it required? An expansion tank is always highly recommended if you have a 'closed-loop system' caused by any kind of check valve or pressure regulating valve installed on your house's water supply line. A common illustration compares having high water pressure in your home to having high blood pressure.

How do expansion tanks work?

Expansion tanks work by equalizing pressure throughout the system. ... As hot water enters the heating system, the pressure in the system increases. As pressure increases, the diaphragm in the expansion tank is pushed down. This compresses the air in the tank, creating more space for excess water to enter.

What happens if you don't have an expansion tank?

As plumbers know, the expansion tank equalizes pressure throughout the plumbing system by providing a space for hot water to flow into. Without an expansion tank, pressure would be distributed to the entire plumbing system, straining it and decreasing its lifespan.

What does an expansion tank do?

How much does an expansion tank cost?

Water heater expansion tank prices start at around $40 and range up to nearly $200; pricing is largely dependent on the size of the tank. For most residential installations with 40- or 50-gallon water heaters, a simple 2-gallon tank is fine.

Is it code to have an expansion tank on water heater?

California Plumbing Code Section 608.3 requires an expansion tank to be installed on the water heater when it is a closed system. A closed system is one that has a check valve, or backflow prevention device.

Can an expansion tank explode?

As water heats up, it can expand dramatically, and if it's hot enough to turn into steam, this can add even more pressure to the water heater. If the relief valve is malfunctioning, this can lead to an explosion.

Where do you put an expansion tank?

An expansion tank is generally installed directly above the water heater by means of a tee-fitting installed in the cold water delivery pipe. The expansion tank is usually installed horizontally, though it is acceptable to install it vertically if it is necessary because of space limitations.

How long does an expansion tank last?

The average life of your tank can be anywhere between five and 10 years. You can extend the life of your expansion tank by making sure that your home's water pressure matches the air pressure in your expansion tank. But in some cases, you'll need to replace it.

Why do I need an expansion tank on my water heater?

Because water will expand when heated, the excess pressure inside the water heater tank needs to be released. ... The expansion tank is designed to handle the thermal expansion of water as it heats up in the water heater, preventing excessive water pressure.

How much does it cost to install an expansion tank on a water heater?

A water heater expansion tank costs $40 to $200 with labor adding another $50 to $150. Most come with a little extra space for fluid expansion as it heats up. It's usually required by code with new construction or when upgrading your current system.

What is the difference between an expansion tank and a pressure tank?

The most significant difference between expansion and pressure tanks is their functionality. An expansion tank handles water expansion and provides protection for water valves and heaters. On the other side, the pressure tank lengthens the lifespan of the pump.

How often should expansion tank be replaced?

Between five and 10 years is the average lifespan of your tank. If your home's water pressure matches the air pressure in your expansion tank, you can extend the life of your tank. You'll need to replace it in some cases.

Does the expansion tank go on the hot or cold side?

Although expansion tanks can be installed on the hot side, we strongly recommend they be installed on the cold line, downstream of the shutoff valve.

How far can expansion tank be from water heater?

The items which should be installed in sequence in the cold water line are (1) the EXPANSION TANK must be installed at least 18 inches away from the cold water inlet fitting on the water heater, (2) the PRESSURE GAUGE, and (3) the PRESSURE REDUCING VALVE, if required, see Figure 1.

How do I know if my expansion tank is working?

The tank should be full of air and therefore sound hollow. If it makes a dull thud rather than a hollow sound, your tank is full of water and needs repair or replacement. You can also gauge this by feeling the tank, which will be cool where it's holding air and warm where it's holding water.

Why does my hot water heater make a popping sound?

The popping sounds are created by bubbles of hot steam escaping the layer of sediment when your water heater is doing its job. The hot water trapped beneath the sediment layer begins to boil, which leads to popping sounds, much like water boiling over a pot's lid on the stove.

Why is my hot water so hot all of a sudden?

If your water heater is making hot water too hot all of a sudden, it's likely the result of the temperature setting being too high, a malfunctioning thermostat, high mineral content, or the pressure relief valve is blocked. Each of these issues can cause the water from the faucet to come out too hot.

How do you know if your boiler is going to explode?

Rotten Egg Odor

The smell of rotten eggs near your water heater is another sign your water heater could burst as it indicates a gas leak. Gas leaks occur due to poor installation, damaged gas lines and other system issues. The water heater's pilot light can ignite the gas, leading to a severe explosion and fire.

Will a bad expansion tank cause low water pressure?

Before installing an expansion tank, measure the tank's air pressure charge. When taken from the box, the air pressure in the expansion tanks will likely be lower than your home's water pressure.

Do all water heaters require expansion tank?

Although many jurisdictions now require an expansion tank to be installed at the same time that a water heater is installed, an expansion tank has not always been required in the past and may still not be required in some regions.

What PSI should my expansion tank be?

The recommended water pressure is between 50 and 60 PSI. Thermal Expansion Tanks contain an air bladder which is pressurized with air, and expands and contracts to absorb the expanded water from the water heater. needed. Check the air pressure in the Expansion Tank using a tire gauge.

Can a expansion tank be used as a pressure tank?

An expansion tank usually has a much smaller inlet hole than a pressure tank. But if it has a full open 3/4" port it can work as either an expansion or a pressure tank.