Do You Need an Expansion Tank for Your Tankless Water Heater?

By SmartHomeBit Staff •  Updated: 06/08/23 •  14 min read

Tankless water heating systems don’t store water, so they don’t usually need expansion tanks. They heat water on demand with a heat exchanger. There’s no stored volume, so pressure doesn’t build up.

Still, sometimes an expansion tank is needed with tankless systems. Like in combination systems with a storage-type heater. Or, in closed plumbing systems with changing water flow. Or, in municipal systems with check valves.

Whenever an expansion tank is used, it must meet International Plumbing Codes. The installation must be done correctly too.

The Importance of Managing Thermal Expansion in Water Distribution Systems

Thermal expansion in water systems must be managed properly. When heated, water increases in volume which can cause pressure build-up. This can lead to issues like burst pipes and leaks. Managing thermal expansion is key.

An expansion tank is a great solution. It gives extra volume somewhere to go when the water heats up. Without it, there could be extra mechanical stress which causes damage.

Not all systems need an expansion tank. For example, tankless water heaters don’t – they only heat up water as needed. But some systems, such as combination systems with a tank heater or a recirculating system, may require one.

Overall, managing thermal expansion is essential. Investing in an expansion tank can help avoid costly repairs or replacements. It’s important to comply with plumbing codes and installation requirements when deciding if you need an expansion tank. Don’t wait for something to go wrong – get an expansion tank now!

The Need for an Expansion Tank in Traditional Tank Water Heaters

Traditional tank water heaters are commonplace in most households. However, many are unaware of the problems thermal expansion can cause on these water heaters. In this section, we’ll explore the necessity of expansion tanks and the risks involved in not having one installed. We’ll also take a closer look at how expansion tanks work in managing thermal expansion in tank water heaters.

How Expansion Tanks Work to Manage Thermal Expansion in Tank Water Heaters

Expansion tanks are essential for tank water heaters. They manage thermal expansion and stop damage. When water is heated, it expands and creates pressure, which could lead to leaks or bursting. An expansion tank gives extra space for the heated water, lessening the pressure and protecting the system.

To comprehend how they work, you need to know they have a pre-charged air cushion and a chamber for water. When the water in the tank expands due to heating, it enters the expansion tank and compresses the air cushion. This allows for the increased volume of hot water and stops pressure buildup.

They come in different sizes and should match the heater or plumbing system. An incorrectly sized tank can be useless and cause malfunctioning or leakage.

You need to manage thermal expansion for good functioning and long life of tank water heaters. Installing an expansion tank is a preventive step against damages from thermal expansion. Skipping it can cause costly and messy water damage. So, it’s better not to ignore this important element.

The Risks of Not Installing an Expansion Tank in a Tank Water Heater

Water expands when heated. Not installing an expansion tank in a tank water heater is risky. Pressure builds up against the closed valve, causing backflow on the water heater tank. This could cause leaks and failure.

Thermal contraction from fluctuating temperatures weakens the container. No expansion tank assistance means excess stress for kitchen and bathroom appliances. This could lead to system failures, disrupting daily activities and requiring costly repairs.

Homeowners must install expansion tanks with traditional tank-type heaters. This reduces the chances of failure when temperatures adjust. A professional plumber service must replace the expansion tank every 3 years or as per state guidelines.

Do Tankless Water Heaters Require Expansion Tanks?

With the increasing popularity of tankless water heaters, a common question that arises is whether or not these systems require expansion tanks. In this section, we’ll take a closer look at the tankless water heating system and explore the reasoning behind why expansion tanks are not typically necessary for this type of system. So, let’s dive in and gain a better understanding of the need for expansion tanks in tankless water heaters.

Explanation of Tankless Water Heating System

Tankless water heaters are a modern and efficient alternative to traditional systems. They heat water only when it is needed, instead of storing it in a tank. This eliminates the need for an expansion tank, as there’s no stored water and no pressure buildup.

When someone turns on a hot water faucet, cold water flows through a heat exchanger. Gas or electricity is used to warm the water. This on-demand system provides an endless supply. It is more energy-efficient and cost-effective than traditional systems.

Sometimes an expansion tank is needed. This might be the case for combination systems, closed plumbing systems, or municipal water supply plumbing systems.

In summary, you don’t usually need an expansion tank with tankless systems. But, if it’s necessary, you must take installation requirements and codes into account. Otherwise, you could face costly repairs or dangerous situations. So, if you’re a stand-up comedian, make sure to remember this!

Why Expansion Tanks are Not Necessary for Tankless Water Heaters

Expansion tanks are usually not necessary for tankless water heaters. This is because they work differently than traditional tank water heaters. They heat water on demand, instead of storing hot water.

In some cases, an expansion tank might be needed for a tankless water heater. An example is when there’s a combination system that includes a tank water heater or recirculation system. Municipal water supply plumbing systems and closed plumbing systems may also have to use an expansion tank, to match international plumbing codes.

When installing an expansion tank, you must think about the installation requirements. Then, put it in the right spot and connect it to the plumbing system. This helps avoid safety hazards or damage.

It’s a good idea to talk to a professional plumber. This way, you can be sure you’re following all the codes and installation techniques. If you don’t manage thermal expansion correctly, it could cause leaks or burst pipes. Installing an expansion tank is like wearing a seatbelt, even with airbags. Better safe than sorry!

When is an Expansion Tank Needed with a Tankless Water Heater?

Tankless water heaters are known for their energy efficiency and long lifespans, but when it comes to installation, there are a few considerations to keep in mind. One of these is whether an expansion tank is necessary. In this section, we’ll explore the situations in which an expansion tank may be needed when installing a tankless water heater. Specifically, we’ll be looking at:

  1. Combination systems with a tank water heater or recirculating system
  2. Closed plumbing systems
  3. Municipal water supply plumbing systems

Combination Systems with a Tank Water Heater or Recirculating System

When it comes to combination systems with a tank water heater or recirculating system, thermal expansion needs to be managed. The expansion tank handles this. It provides a safe place for expanded water to go.

To understand the importance of this, let’s look at a table. It shows whether an expansion tank is required for different systems.

System Expansion Tank Required? Explanation
Combination with traditional tank water heater Yes Expanded water from heated tanks can’t backflow into incoming cold water supply
Combination with recirculating system Yes Hot water constantly circulating, so there’s no way for expanded water to escape to incoming cold supply

Not having an expansion tank can lead to costly repairs. That’s why it’s wise to consult a professional plumber during the installation process. They can tell you what the specific requirements are, including relevant codes.

In summary, an expansion tank is necessary for a combination system with a tank water heater or recirculating system. This will ensure optimal performance and protect your plumbing system from damage.

Closed Plumbing Systems and Municipal Water Supply Plumbing Systems

Thermal expansion is a major factor in water heating systems – especially ones with closed plumbing or municipal water supply plumbing. Pressure build-up from thermal expansion can lead to severe pipe and water heater damage.

To reduce this risk, an expansion tank is necessary. It serves as a reservoir for the extra water volume created by thermal expansion, preventing pressure build-up and damage.

Not all tankless water heaters need an expansion tank. But if you have a combination system with a tank water heater, a recirculating system, or a closed plumbing/municipal water supply system, then an expansion tank is a must.

Also, installation of an expansion tank needs to comply with international plumbing codes for proper function and safety. If these requirements aren’t met, water damage can follow. An example: a homeowner installed a tankless water heater without an expansion tank in their closed plumbing system. This led to burst pipes and costly repairs which could have been avoided.

Conclusion: Be sure to expand your knowledge on the importance of compliance and installation requirements for tankless water heaters and expansion tanks, especially in closed plumbing and municipal water supply plumbing systems.

Other Factors to Consider with Tankless Water Heaters and Expansion Tanks

When it comes to tankless water heaters, there are other factors to consider beyond just the need for an expansion tank. In this section, we will discuss two key factors that are crucial to ensure that your tankless water heater operates efficiently and safely. Specifically, we will explore compliance with international plumbing codes and the installation requirements for thermal expansion tanks. With these important considerations in mind, you can make informed decisions about your tankless water heater installation and ensure the longevity of your system.

Compliance with International Plumbing codes

Installing a tankless water heating system requires compliance with international plumbing codes. These codes provide the rules and regulations for safe installation and operation of any plumbing system. For example, Universal Plumbing Codes (UPC) and International Plumbing Code (IPC) have specific guidelines for thermal expansion tanks.

These requirements vary, depending on the size, location, and type of water heater. Some jurisdictions may not require an expansion tank at all. It’s important to check the codes before installation. Ignoring them can result in penalties and damage to the plumbing system.

Aside from the codes, proper installation is also necessary. This includes following manufacturer specifications and using the right materials and tools. Professional installation may be required for those without experience.

In conclusion, complying with international plumbing codes is essential when considering an expansion tank for a tankless water heater. This promotes safe and efficient operation of the plumbing system and minimizes risks from thermal expansion.

Installation Requirements for Thermal Expansion Tanks

Thermal expansion tanks are key for any plumbing system. Knowing how to install them is vital.

  1. First, figure out the proper tank size. This is so pressure build-up does not damage any plumbing or appliances. The size depends on the water heater capacity.
  2. Next, install the tank in the right spot. This could be either vertical or horizontal, depending on space.
  3. Connect the tank to the plumbing system. This is usually done using a T-fitting on either a hot or cold water line near the heater. Some areas require permits for expansion tanks, so be sure to follow regulations.

When installing, consider the nearby codes and regulations, tank size, model compatibility, and permits. Also take into account international plumbing codes like IPC and PEX. Following these guidelines will create a system that manages thermal expansion and works well.

Conclusion: The Verdict on Expansion Tanks for Tankless Water Heaters

The verdict is clear – expansion tanks are a must-have for any tankless water heater system! They absorb excess pressure and keep optimal pressure levels. This contributes to efficiency and extends the system’s lifespan.

The size of the expansion tank should match the water heater. The material should be corrosion-resistant. A licensed plumber can help with installation.

Maintenance is also key. Pressure checks and leak inspections should be done regularly. This ensures the tankless water heater system will be successful long-term.

FAQs about Tankless Water Heater Need Expansion Tank

Do tankless water heaters need an expansion tank?

Tankless water heaters do not need an expansion tank in most cases because they produce hot water on demand and do not store water. Any potential pressure build-up in a tankless system is relieved by the fact that water is not stored in a tank.

What should I do if something went wrong and I need to try again?

If something went wrong while using a tankless water heater, it is best to wait a moment and try again. This may solve the issue and prevent further complications.

Is an expansion tank required for a water distribution system with a tankless water heater?

In most cases, an expansion tank is not required for a water distribution system with a tankless water heater. However, if a storage tank is used in conjunction with a tankless water heater in a closed system, which is sometimes the case with recirculation, then a means of controlling thermal expansion must be provided.

Are expansion tanks required for tank water heating systems?

Yes, expansion tanks are required for tank water heating systems. These systems have a tank that constantly cycles on and off to keep water hot, causing water to expand. An expansion tank serves as a pressure relief valve for the main water tank in tank water heating systems.

Why are thermal expansion tanks necessary?

Thermal expansion tanks are necessary to control pressure caused by thermal expansion. Without a place for pressure to release during thermal expansion, tank-style water heaters could explode. A thermal expansion tank is a safety device used to reduce the risk of pressure damage to the plumbing system.

Do tankless water heaters save energy and space?

Yes, tankless water heaters are becoming more popular due to their on-demand hot water and space-saving design. They only heat up the exact amount of water needed, resulting in energy efficiency and longer lifespan.

SmartHomeBit Staff