Installation and Replacement Guide for Water Heater Parts (Exploring the Main Components)

Water heaters are essential appliances that provide a steady supply of hot water for various purposes. However, like any other device, water heaters can malfunction and require repairs or replacements over time.

Understanding the different parts that make up your water heater and how to install or replace them can help you maintain system efficiency and reliability. This can save you money on energy bills and extend the lifespan of your water heater.

In this guide, we will explore the main components of water heaters, such as the gas valve, thermocouple, pilot light, and anode rods. We will also provide tips on how to install and replace them to keep your water heater running smoothly.

Combining these instructions with our troubleshooting guide can make repairing or replacing broken parts easier.

It's important to note that this article mainly reviews parts of storage gas and electric tank heaters, as they are the most common source of residential water heating. If you own a tankless heater, you can still use this article to learn more about the main tankless components.

The main gas and electric water heater parts

In addition to standard components, many advanced residential water heaters include components for efficient heating operation and increased safety, such as heat traps, powered draft hood, hot surface ignitor, flame arrestor, powered anode rod, and dry-fire protection. These components provide longer warranty, higher savings, comfort, and higher initial prices.

If you want to upgrade your water heater with quality elements to increase performance, efficiency, and the heater's life, you can contact a professional plumber.

Storage water tank

The majority of the water storage tank heaters are equipped with tanks made of carbon steel, while some models, such as Rheem Marathon, utilize a plastic tank, or Westinghouse uses a storage tank made of stainless steel. Such a construction automatically eliminates the need for an anode rod, corrosion protection, and frequent maintenance.

Due to the corrosive water action, water heaters equipped with metal tanks must include the glass/ceramic lining and anode rods.

The main purpose of the storage tanks is to store hot water. Tanks are wrapped in insulation so they can longer retain the hot water. And with the thicker insulation, the unit becomes more efficient. Typical insulation types are fiberglass and polyurethane foam that come with a thickness of 2 and 3 inches.

Gas valve

Robertshaw, White-Rodgers, and Honeywell are three of the most commonly used gas control valves for gas water heaters. The gas valve is the most important component of a water heater as it controls the delivery of natural or propane gas to the main burner and pilot light while also serving as a safety device.

The gas control valve also contains the thermostat. By turning the knob, you can increase or decrease the temperature of the hot water output. Gas control valves from the aforementioned manufacturers typically include a gas control knob, reset button, high water temperature limit safety, and temperature dial. Some advanced valves feature a diagnostic system for troubleshooting and more accurate temperature control.

If you need to replace a gas control valve, check out this guide on how to do it properly.

Heating elements

Electric heating elements are the source of heat in electrical appliances and are usually found as the upper and lower elements on tall units. Smaller models are often equipped with only one element. These electric water heater parts can also be found in solar heating systems and heat pumps used for backup heating.

In addition to protecting the electric elements, some water heaters are equipped with the dry-fire feature, which protects the elements if they are exposed to the air.

Use this article to get more information on replacing water heater elements.

Anode rod (sacrificial anode)

The anode rod is an essential component that protects the steel tank from corrosion, along with the tank's glass or ceramic lining.

The anode rod is often referred to as a sacrificial anode, as it sacrifices itself to extend the life of the tank. Some models come with a powered anode that is not sacrificial, which is found on better models.

Anodes are typically made of zinc, magnesium, or aluminum and are installed on the top of the unit, making them easy to replace when necessary.

Take a look at our comprehensive guide to learn everything you need to know about replacing an anode rod, including its impact on water heater performance, the best type to use, and common problems to watch out for.

Venting and flue pipes

The venting system is designed to exhaust the products of combustion through the flue baffle and vent pipes, and in some models, to draw in the fresh air required for proper gas combustion.

You can find various types of venting systems based on your preference, home design and construction, location of the heater, and other requirements.

These include atmospheric, power, direct, and power direct vent systems. Additionally, there are two-pipe closed combustion systems that draw fresh air from outside the home and eliminate issues caused by insufficient indoor ventilation.

You can also choose from two-pipe or one-pipe atmospheric vent systems with a draft hood and a concentric vent system, which consists of two pipes (a pipe within a pipe) and can be used with or without an electric-powered blower.

It's essential to remember that different types of venting systems require different venting materials, such as stainless steel, PVC, or sheet metal.

Blowers

The electric blowers use a 110/120-volt electrical system, usually rating 3 amps or less, and are equipped with a 6-foot cord.

Electric blowers are typically installed on top of the water heater from where it pushes the exhaust and excess heat to the outside atmosphere.

Dip tube

Dip tubes are an essential component of water heaters as they facilitate the flow of cold water into the tank.

They connect the cold water inlet and extend almost to the bottom of the tank, with about 6 inches of clearance. Different types of dip tubes are used, depending on the model and manufacturer.

For instance, Bradford White utilizes the perforated tube, which creates a turbulent flow that minimizes sediment and scale buildup. This results in maximized hot water output, providing you with more hot water for your daily needs.

In addition to bringing cold water into the tank, the dip tube enables water to circulate freely, reducing the risk of sediment buildup. Consequently, the water heater's performance is optimized, ensuring that you have hot water whenever you need it.

Fortunately, replacing a dip tube is a simple process that can be done easily.

Gas burner assembly

Gas-powered appliances feature a crucial element known as the gas burner assembly, comprising multiple components:

Main burner. This is the heat source of gas water heaters, located below the storage tank. Advanced models from manufacturers such as Rheem, AO Smith, and Bradford White use eco-friendly burners that reduce NOx emissions by one-third compared to standard burners.

Orifice. When converting the water heater from natural to LP gas, the burner orifice should be replaced.

Manifold tube. This part includes the pilot burner/pilot light with the pilot tube and orifice. On water heaters with a pilot light, the pilot burner remains on once it is manually lit, and it is used to ignite the gas. Some manufacturers use hot surface ignitors or electrodes instead of the pilot flame.

An igniter like a piezoelectric or hot surface is used to light the gas.

Thermocouple. A thermocouple is a safety part used to send a signal from the pilot light to the gas control valve to control the gas delivery. It generates a small electrical current, enough to signal whether the flame is present or not.

A thermopile does the same thing as a thermocouple, converting heat into electrical energy, but it's composed of several thermocouples connected in series, increasing its ability to produce electricity.

If your water heater isn't producing hot water, you may need to inspect and replace a thermocouple or a broken pilot light.

ECO

The ECO, also known as the Energy Cut Off, is a vital safety feature present in gas water heaters. 

It is essentially a metal tube, also known as a temperature probe, that is mounted on the back of the gas valve and is immersed inside the water tank. Its primary function is to act as a temperature high limit, ensuring that the water temperature does not exceed a safe level.

TCO

The TCO, or Thermal Cut Off Switch, is a resettable thermal switch designed to shut off the gas supply if the temperature of the products of combustion becomes too high.

Thermostats

Mechanical thermostats are commonly used in standard residential water heaters, with factory settings usually set to 120°F to prevent scalding water. However, these thermostats operate with a certain tolerance.

If you require assistance in replacing a thermostat on an electric water heater, refer to the instructions provided in this guide.

FVIR and flame arrestor (or arrester)

The fireproof flame arrestor is is part of the FVIR (Flammable Vapor Ignition Resistant) technology utilized in water heaters to prevent accidental or unintended ignition of flammable vapors. It is typically built into the base of the water heater and made of fire-resistant materials like stainless steel or ceramic. The flame arrestor functions by blocking the flame from escaping the gas combustion chamber.

TPR valve

The TPR valve, also known as the temperature and pressure relief valve, serves the important function of safeguarding the water heater system from excessively high water temperature and pressure. It is typically paired with a discharge pipe that directs water to a suitable drain. These components are factory-installed and are mandatory for all tank-type water heaters as per code.

If you notice that the valve is not functioning correctly, it is not advisable to attempt to repair it. Instead, use the step-by-step instructions in this guide to replace it yourself.

Drain valve

Water heater drain valves are present on all types of water heaters and are typically made of plastic or brass. Drain valve are designed for draining, flushing, and maintenance.

It is recommended to use a brass drain valve as they are more durable and have better quality. Plastic drain valves are prone to damage, particularly around the threads, making them more susceptible to leakage.

Replacing this part is another simple task that can be done easily by following a step-by-step replacement guide.

Air pressure switch

The air pressure switch is found in gas water heaters that use an electric-powered blower to vent combustion products. It is used in all power vent and power direct vent heaters to ensure that the operational conditions are met.

Insulation

Manufacturers of hot water heaters use different foam thicknesses to provide various energy and heat waste savings, improved efficiency, and better performance. Some models come with high-quality insulation, such as 2" or 3" foam, while less efficient models may benefit from an insulation blanket.

Timers

Installing an electric water heater timer is an effective way to reduce energy consumption and save money. The timer is specifically designed to turn off the water heating during periods of inactivity and turn it on when needed, providing significant cost savings over time.

Mixing valves

Hot water mixing valves are commonly used in residential water heating for showering, bathing, and hand-washing. Their main function is to reduce the point-of-use temperature by mixing hot and cold water in the branch water line, providing a safe and comfortable temperature for the user. By installing a hot water mixing valve, homeowners can not only prevent scalding accidents but also save on energy bills by reducing the need for excessively high water temperatures.

Recirculating pumps

If it takes too long to get hot water from your kitchen and bathroom fixtures, consider installing a recirculating pump. These pumps are designed to deliver hot water on demand, eliminating the need to wait for the water to heat up.

More advanced pumps come equipped with sensors and timers for better control, ensuring that hot water is available exactly when and where it's needed.

For a fully recirculating pump system, a loop is installed from the water heater to the faucet and back, leaving no water inside the pipes. Alternatively, there is a system that utilizes an existing cold water pipe to send unused water back to the water heater.

The main benefits of installing a recirculating pump include a continuous flow of hot water, hot water always being available at the point of service, and water and energy savings.

Expansion tanks

Expansion tanks are designed to protect the water heating system by accepting excess water volume when water is heated and during high pressure inside the water heater. These tanks are used on closed systems and are considered safety devices.

How to order repair parts

What you should know when ordering gas or electric water heater parts:

• Have the complete part number and description ready.
• Have the water heater model, series, and serial number ready.

Note: If any part of the water heater has been exposed to excessive moisture, you should contact a qualified service technician for the repair. If the water heater has been subjected to flood conditions or any of its parts, including gas controls, the main burner, the pilot light, was submerged in water, an entire water heater should be replaced.

FAQ

Aare water heater parts universal?

No, water heater parts are not universal. Different brands and models of water heaters may require specific parts that are designed to fit and function properly with that particular model. It is important to have the correct part number and description, as well as the water heater model, series, and serial number, when ordering replacement parts. Using incompatible parts can result in malfunction or damage to the unit.

What parts commonly fail on water heaters?

Water heaters are complex systems made up of several parts that can experience wear and tear over time. The most commonly replaced parts are the heating elements, thermostat, anode rod, T&P valve, and pilot assembly. Regular maintenance can help prolong the life of these parts and prevent unexpected failures.