Are expansion tanks mandatory?

While expansion tanks are required by code in most closed-loop water heater systems, they have a reputation for failing. Common expansion tank issues include: Rubber Diaphragm Wear Out.

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

In a “closed” plumbing system, water can’t flow back into the city water lines once it enters your home’s plumbing. Now that might not seem so bad but if you don’t have an expansion tank, a closed system doesn’t give expanded water any route for escape, causing damage to your home’s water heater and plumbing.

Is an expansion tank required by code?

The California Plumbing Code (Section 608.3) and the California Mechanical Code (Section 1005.0) requires a thermal expansion tank, or listed equivalent, to be installed to water heating systems to relieve excessive building pressure during the heating process.

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

The cost to install a thermal expansion tank can range from $300 to $400. Often the expense of the thermal expansion tank is included in the cost of the new water heater.

How big should an expansion tank be?

In fact, if unsure that your expansion tank will be able to safely accommodate your system, it is common practice to choose an expansion tank that is one size larger than the required size. As a general rule of thumb with expansion tanks, it is better to oversize than to undersize.

What causes an expansion tank to fail?

The first is an air compartment with the pressure set to allow room for the water to expand into, but not to fill the entire tank. When this happens, the expansion tank turns into a “dead leg” that will eventually cause damage and premature failure to your water heater.

Where does an expansion tank go in a water heater?

An expansion tank looks like a mini tank or boiler, and typically sits on top of, or adjacent to, the water heater. They come in many different sizes, depending on your water pressure, the size of the actual water heater, and the temperature the water is heated to.

Can a large expansion tank cause relief valve discharge?

The standard is to select an expansion tank that is larger than necessary rather than select one that is too small. This is because a tank that is too small can cause relief valve discharge. On the other hand, if the tank is too big, it has no negative impacts on your plumbing.

What should the pressure be in an expansion tank?

The importance of pressurizing the air is that it determines the pressure that the chilled water must achieve before the expansion tank accepts volume. For example, the closed tank has a pressure of 14.7 psia. As the chilled water pressure increases above 14.7 psia, the chilled water will flow into the expansion tank.

How does an expansion tank ( CHW ) work?

It is simply a closed tank with a connection to the chilled water system. The closed tank has extra space that is filled with air, when the temperature in the system is cold. As the temperature within the chilled water system rises, the volume expands and fills the empty space within the tank. Expansion Tank (CHW)-4 http://www.engproguides.com

What should I do before adding water to my expansion tank?

1. Pressurizing the air side of the tank to equal the static pressure of the water at the expansion tank location and before adding water to the system. This prevents cold water from partially compressing the air in the tank. The diaphragm only begins to compress when the water temperature rises. 2.

Do you need a strapping kit for an expansion tank?

Some expansion tank manufacturers offer strapping kits or other hardware to properly support the tank shell. In addition to the strapping notice both tanks have isolating balls and sufficient room for accessing the Schrader air valve at bottom.

What’s the increase in volume in an expansion tank?

The higher the concentration of antifreeze the greater the expansion volume required. The increase in volume for water heated from 60F to 180F is about three per cent. The increase in volume for a 50 per cent solution of propylene glycol heated from 60F to 180F is about 4.5 per cent.

What does an expansion tank on a water heater look like?

Are expansion tanks mandatory?