Pressure relief tank for hot water heater

If you have a “closed system,” meaning there is a backflow preventer or other device that won’t’ permit your water to flow back into the main water supply, thermal expansion will lead to significant pressure increases in your home’s plumbing system. 

Not only should you have a thermal expansion tank under these circumstances, but some municipalities require it. Further, your water heater’s manufacturer might void your warranty if you have a closed system and fail to get this safeguard. 

You don’t need a water heater expansion tank if you have a tankless water heater since there is no tank and no buildup of pressure. Likewise, if your home runs on an open water supply system, where excess water goes back into the municipal water supply, it won’t place any strain on your home’s plumbing system. 

When heated, water expands. Under normal circumstances, a 40 gallon hot water heater creates roughly an additional half gallon of water when heated. In the past this expanded water would flow back into the public water supply.

Thermal Expansion tanks are used to prevent plumbing system and/or water heater damage and unnecessary relief valve discharge caused by excessive pressure from thermal expansion.

Because water expands when heated, excess pressure inside a water heater tank needs to escape. In the past, the pressure would force water in the tank to drain back out into the water supply where it came from.

Today, the water main is designed to prevent the backward flow of water, known as backflow, by means of a check valve. The check valve prevents wastewater from inside the home from returning to the water supply, where it could contaminate the supply of fresh water.

How a Water Heater Expansion Tank Works

A water heater expansion tank is another small tank that is attached to the water supply pipe of the water heater. The expansion tank is designed to handle the thermal expansion of water as it heats up in the water heater, preventing excessive water pressure.

If water pressure gets too high, it can damage valves in plumbing fixtures, joints in supply pipes, and the water heater itself. Expanding water from the water heater flows into the expansion tank, relieving water pressure in the system.

Have more questions about water heater expansion tanks? Contact the experts at ABC Southwest for answers!

What if my water heater doesn’t have an expansion tank?

Most homes that have a check valve on the water main do not have an expansion tank, since it wasn’t required until recently. This may or may not cause excessive pressure buildup, depending on the specific design of the plumbing in the house.

If you are noticing that washers in plumbing fixtures are deteriorating rapidly, or water is dripping from the relief valve on the water heater, it may be wise to add an expansion tank. It can be low-cost insurance against more costly damage to your home’s plumbing system.

Ready to install a water heater expansion tank in your Sarasota-area home? Schedule now with the water heater experts at ABC Southwest!

When it comes to keeping your customers comfortable, a water heater system plays a significant role. However, unbeknownst to the homeowner, not all parts of the system are efficient or reliable enough to maintain uninterrupted comfort.

In particular, expansion tanks are one of those items that tend to need replacing before other parts of the system. At RWC, we’ve listened to Pro feedback on the short lifetime of expansion tanks and created a more dependable solution.

SharkBite’s new Thermal Expansion Relief Valve provides a longer lasting alternative for your customers. It replaces the bulky expansion tank, shut-off valve and fitting right at the water heater for an easier-to-install solution. 

Similarities Between Thermal Expansion Relief Valves & Expansion Tanks

The Thermal Expansion Relief Valve can replace a water heater expansion tank because it functions similarly. Both products absorb the excess pressure in the plumbing system created by thermal expansion. 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.

Like an expansion tank, the new Thermal Expansion Relief Valve also takes the load off your pipes by:

• Equalizing pressure
• Managing thermal expansion of water
• Keeping pipes from bursting or wearing out prematurely

Instead of storing water, though, the Thermal Expansion Relief Valve releases it, solving some of the problems that come with using an expansion tank.

Common Expansion Tank Problems

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. The pressure below the rubber diaphragm in the tank may not have been set at the right level during installation, for example, allowing water to enter the tank too frequently and wearing out the diaphragm prematurely.
• Pinhole Leaks. Expansion tanks are also known for developing pinhole leaks in the rubber bladder, and there’s no way to know without going out of your way to test it or by noticing that the Temperature & Pressure Relief Valve (T&P) is going off frequently.
• Excessive Condensation Issues. Tanks can also become coated in condensation if there’s too much water in the tank, for instance, which can lead to messy pooling, dangerous dripping and eventually a rusty expansion tank.

Because there are coordinating valves and parts both outside and inside a water heater that determine whether water pressure is effectively and safely managed, there are many failure points that could lead to damaged plumbing systems — all without warning.

Why the Thermal Expansion Relief Valve is the Better Option

When you need more time in your day and want to keep your customers happy, you need reliable solutions that help you finish the job faster while remaining cost effective. Here are a few ways SharkBite’s new Thermal Expansion Relief Valve sets you up for success.

Dependability

There’s no guesswork with the Thermal Expansion Relief Valve. Installed in the same place as an expansion tank, it’s a combination of a ball valve with a relief valve that opens and drains water to a pipe drain once water pressure hits 125 psi. That means no wondering if a diaphragm or bladder is working properly, no inevitable replacement. And the best part? It meets code requirements.

Installation

It’s easier for you to install, too, since there are no bulky items to work around when putting everything in place. No matter how big or small the area around the water heater is, you don't have to worry about finding space for a tank anymore. Made with SharkBite push-to-connect end connections that are compatible with PEX, copper, CPVC and PE-RT pipe, the Thermal Expansion Relief Valve simply goes onto the water line — no extra support needed.

Cost

And with ease comes more affordability. All you need is the Thermal Expansion Relief Valve and a drain line, whereas an expansion tank requires several additional accessories that add up.

Get Started

While expansion tanks have been the norm to keep thermal expansion from damaging plumbing systems, they come with reliability issues, extra installation costs and the need for space. We created the Thermal Expansion Relief Valve to give you the functionality of an expansion tank without its problems.

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Do I really need an expansion tank on my water heater?

If your home has a “closed” plumbing system, then yes, you'll need an expansion tank. You see, homes have either an open or a closed plumbing system. A closed plumbing system prevents water from flowing in the reverse direction (i.e., water won't flow back into city lines once it enters your home's pipes).

What is the purpose of a pressure tank on a hot water heater?

The expansion tank is designed to handle the thermal expansion of water as it heats up in the water heater, preventing excessive water pressure. If water pressure gets too high, it can damage valves in plumbing fixtures, joints in supply pipes, and the water heater itself.

Where should a water heater pressure tank be installed?

Your expansion tank can be anywhere on your plumbing system and does not need to be installed in close proximity to the water heater. It is most commonly installed using a “T” at the cold inlet to the water heater. But, functionally, it can be installed anywhere on the cold inlet line.

How much air pressure should be in a hot water expansion tank?

Expansion tanks are pre-charged with a 40 PSI air charge. If the inlet water pressure is higher than 40 PSI,the expansion tank's air pressure must be adjusted to match that pressure but must not be higher than 80 PSI.