Hot Water Heater Parts Explained: What You Need for Repairs & Maintenance

Hot water heaters may seem like single, self-contained appliances, but they're actually a system of interconnected components working quietly behind the scenes. Knowing how these pieces function can save you money, reduce downtime, and help you find the right hot water heater parts when it's time to repair or replace.

Let’s break down the most essential components by type of systemю We’ll give you a clearer picture of what each part does, when it might fail, and how to spot the right replacement.

Why Knowing Your Water Heater Parts Matters

You don’t have to be a licensed plumber to benefit from a basic understanding of your water heater’s inner workings. If you're a homeowner, facility manager, or DIY enthusiast, this knowledge gives you:

• Faster troubleshooting when issues arise

• Confidence in choosing the right replacement parts

• A better understanding of maintenance cycles

• Peace of mind when speaking with technicians
  

At Voomi Supply, we help customers find hard-to-find parts every day, especially when other retailers don’t carry the right SKU or brand.

Common Parts of a Hot Water Heater (All Types)

Let’s start with the basics. These are components found in most tank-style water heaters, regardless of whether they’re gas or electric.

Cold Water Inlet & Dip Tube

The cold water inlet allows fresh water to enter the tank. The dip tube directs that water to the bottom of the tank, so it doesn’t mix immediately with hot water at the top. If the dip tube cracks or breaks, your water may feel lukewarm.

Temperature & Pressure Relief Valve (T&P Valve)

This is a key safety feature. If internal pressure or temperature gets too high, the T&P valve releases water to prevent damage or explosion. A faulty T&P valve can cause leaks or dangerous pressure buildup.

Drain Valve

Located near the base of the tank, the drain valve allows you to empty the tank for flushing or service. Sediment buildup can clog this valve over time.

Anode Rod

This metal rod “sacrifices” itself to prevent your tank from corroding. Anode rods typically need replacing every 3-5 years. They come in magnesium, aluminum, or zinc, and Voomi Supply carries all three, including powered anode options.

Hot Water Outlet

Once water is heated, it exits the tank through this pipe. If you’re not getting hot water at your taps, a blockage or cross-connection issue here could be to blame.

Key Hot Water Heater Parts: Gas Models

Gas water heaters are extremely common in residential and light commercial applications. They heat water quickly and operate on natural gas or propane. Here are some of their unique components:

Gas Burner Assembly

This includes the burner, jacket door, and pilot assembly at the base of the unit. It’s where combustion occurs, heating the water from below.

Pilot Light / Igniter

Older models use a standing pilot flame. Newer ones use an electronic ignition system. If your water isn’t heating, a failed igniter or dirty pilot orifice could be the cause.

Thermocouple / Flame Sensor

This safety device shuts off gas if no flame is detected. If the thermocouple fails, the burner won’t ignite. Even if everything else is working.

Gas Control Valve

Regulates gas flow and connects to the thermostat. It’s a common failure point in older heaters and can often be replaced without replacing the entire unit.

Flue Baffle & Draft Hood

These components channel and vent combustion gases. The flue baffle improves heat transfer, while the draft hood or blower assembly (in power vent models) ensures safe exhaust.

Flammable Vapor Sensor (FV Sensor)

Modern gas heaters include this sensor for added safety. If flammable vapors are detected, the sensor will shut down the unit until the issue is resolved.

Key Hot Water Heater Parts: Electric Models

Electric water heaters don’t burn fuel, so their heating mechanisms are different—but equally important.

Heating Elements

Electric units usually have two heating elements: one near the top, one near the bottom. If one element fails, water may not get as hot—or take much longer to recover.

Thermostats

Each heating element is controlled by its own thermostat. These are user-adjustable (usually behind a panel) and maintain the set water temperature.

Power Supply / Breaker

Electric units rely on a dedicated circuit. If the unit isn’t turning on at all, the issue could be a tripped breaker, blown fuse, or damaged power cord.

Tankless Water Heater Parts: What’s Different?

Tankless models work on-demand. Instead of heating and storing water, they heat it as it flows through. Here are some components unique to tankless systems:

Flow Sensor

Detects when water is moving through the unit and activates heating. If the flow sensor is clogged or faulty, no hot water will be produced.

Heat Exchanger

This is the heart of a tankless system. It rapidly heats water as it passes through. Mineral buildup can reduce efficiency, which is why regular descaling is critical.

Control Board

Modern tankless heaters often include digital displays, error code systems, and remote controls. These control boards manage temperature, ignition, and diagnostics.

Add-On Components That Make a Big Difference

Beyond the core parts, there are several accessories and secondary components that improve performance and extend the life of your heater:

Expansion Tanks

These small auxiliary tanks absorb pressure from thermal expansion. They’re often required by code and can prevent damage to your main tank and plumbing.

Recirculation Pumps

Especially useful in larger homes or commercial settings, these pumps help deliver hot water faster by keeping a loop of warm water ready near the fixture.

Insulation Jackets & Pipe Wraps

These inexpensive additions reduce heat loss and improve energy efficiency—especially in colder climates.

When to Replace vs. Repair

Sometimes, replacing a faulty part is all you need. Other times, you might be better off replacing the entire unit. Here’s a quick breakdown:

When in doubt, consult your unit’s manufacturer or contact Voomi Supply for part compatibility checks. We’re here to help you find reliable water heater replacement parts that match your model, fuel type, and install conditions.

Get the Right Hot Water Heater Parts at Voomi Supply

At Voomi, we understand how frustrating it can be to track down a specific part, especially if you’re dealing with an older unit or less common brand. That’s why we stock a broad inventory of hot water heater parts, including:

• Dip tubes, T&P valves, and anode rods

• Gas burner assemblies and thermocouples

• Electric heating elements and thermostats

• FV sensors, igniters, and control boards

• Full retrofit kits and diagnostic tools

Our online catalog is designed to help you find exactly what you need. If you’re not sure, our team is here to help with fitment questions, alternative options, and best practices.

Choose Quality Parts, Backed by Experts

Having the right parts and the right support makes all the difference. At Voomi Supply, we go beyond the basics. Every part in our store is backed by the same trust, reliability, and speed that have defined our brand from day one. We're proud to be the one-stop shop for HVAC, plumbing, and hard-to-find electrical and water heater parts that pros trust.

Explore our collection today, or reach out for tailored recommendations.