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Water Heater Installation Guide

All About Water Heater Installation

turning the cold water off

The humble water heater plays an essential role in modern household comfort, but you may not think about it until it fails to deliver hot water for your daily needs. Most water heater installations last the long haul, toiling in near silence as you take showers, wash clothing and dishes, and clean up household messes for 10 to 15 years. As reliable as water heaters are, however, they do eventually come to the end of their useful life spans.


When breakdowns occur beyond changing elements or thermostats, they usually happen all at once, leading to a sense of urgency for water heater replacement. Fortunately, replacing a water heater doesn’t have to be stressful. 



Learn what it takes to replace your water heater, whether you have an electric, gas or tankless model, and discover why getting professional help for a new water heater installation can save you time, frustration and, most of all, money.

Plumbing Professional

Find A Local Water Heater Pro

A. O. Smith water heaters are professionally installed by local independent contractors.

Things to Consider

New water heater installation ensures a reliable supply of hot water to your home, but safety takes top priority during the process. Whether you’re preparing for electric, gas or tankless water heater installation, take these important factors into consideration.


Water Heater Removal

Before you remove your old water heater, look in the manual for details about safe disconnection and removal. Likewise, examine all labels on the appliance for additional information. Once you understand the removal process, keep in mind you may need specialty tools.


Electrical Updates

If you’ve had your water heater a long time, your home may require electrical updates to handle the new unit's voltage and amperage, so consider whether the new and old specifications match. If they don’t, you need to upgrade your electrical system to prevent accidents and overloads.

Wiring and connectivity may also be an issue with new water heater installation, requiring an experienced hand to perform meticulous tasks. Since incorrect wiring may lead to fires, short circuits and electrocution risks, it’s best to use a professional for water heater installation when you need electrical issues corrected.


Fuel Source Conversion (If Necessary/Desired)

If you have an electric water heater currently and are switching to a gas water heater installation, consider the extras that go into the process. For instance, if you don’t have a gas line to your water heater location, you need a professional gas fitter to perform the installation to prevent explosions, fires or gas leaks. 

Proper ventilation matters for gas water heater installation as well, ensuring safe gas expulsion from your home. This means your home needs adequate ventilation for the appliance, so it may require modifications before gas water heater installation.


Cost of Labor, Materials and Parts

Though you naturally want to save money on water heater installation costs, never compromise on safety. Paying a professional the labor cost to install a water heater is worth it if you’re not confident in your DIY skills or the installation requires skills outside your wheelhouse. 

Likewise, when setting your budget for parts and materials, invest in a high-quality unit that’s well suited to your home rather than picking the cheapest option. Top-notch units, parts and materials help minimize risks of leaks and malfunctions for peace of mind in your water heater installation.



Permits and Inspection

Municipal regulations for water heater installation vary, but many require permits and inspections to comply with building codes and safety standards. Your local building department should have the information you need when you get a permit. Then, after you finish, you may have to schedule an inspection to confirm safe water heater installation.



Professional vs. DIY Installation

The biggest decision you face at the beginning of the water heater installation process is deciding if you should go the DIY route or hire a professional installer. Hiring a pro is often your best bet when it comes to safety. These professionals have expertise dealing with gas lines, water lines, and electricity, plus they have the tools necessary for almost any occurrence, whether it’s for a gas tank, electric tank or tankless water heater installation. And even with water heater installation support, you may save money now, but end up paying more later if issues arise from an unsafe setup. Always install any water heater by referring to the installation manual.

Benefits of Professional Installation

While you might be tempted to DIY, enlisting a professional installer ensures safe water heater installation by an expert with the tools and time to handle the task.



Safety 

Professional installation means using skilled technicians well-versed in regulations and safety protocols — plus the specifications of various water heater models. If you need gas water heater installation, professionals prevent potential hazards with gas leak detection and ensure your home has proper ventilation to remove harmful gasses like carbon monoxide. Local installers are also familiar with the area’s building codes, so they handle permitting and inspections.



Expertise

Handling the complexities of water heater installation requires technicians with lots of training and experience. This expertise also simplifies troubleshooting when unexpected issues or complications arise, letting them diagnose and fix problems quickly. Professional water heater installation may also future-proof your home since professionals advise you on sizing your water heater to match your home.

Not sure which water heater is the best fit for your needs? Get started with our water heater selector to find the right model for your home.


Tools

Whether you’re having a gas, tankless or electric water heater installed, professional installers have all the necessary tools and equipment. They come prepared with sealing and insulation for your unit, which minimizes heat loss and saves energy. The right tools and knowledge also helps ensure the job is being done safely and correctly, which may reduce risks of breakdowns later.



Time

Professional water heater installation almost always saves you time unless you’re a skilled professional yourself. The expertise gleaned from training and years of putting that training to use makes professionals more efficient, and that means minimal disruption to your daily routines.

Enjoy the peace of mind that comes with hiring a professional — find a professional installer to handle your hot water heater installation.

Tools

Whether you’re having a gas, tankless or electric water heater installed, professional installers have all the necessary tools and equipment. They come prepared with sealing and insulation for your unit, which minimizes heat loss and saves energy. The right tools and knowledge also helps ensure the job is being done safely and correctly, which may reduce risks of breakdowns later.



Time

Professional water heater installation almost always saves you time unless you’re a skilled professional yourself. The expertise gleaned from training and years of putting that training to use makes professionals more efficient, and that means minimal disruption to your daily routines.

Enjoy the peace of mind that comes with hiring a professional — find a professional installer to handle your hot water heater installation.

Plumbing Professional

Find A Local Water Heater Pro

A. O. Smith water heaters are professionally installed by local independent contractors.

How to Install a Water Heater

opening water heater box

Before You Begin

Before you begin your water heater installation, keep these considerations at the forefront. Remember: hiring a professional is always an option if you're unsure you can handle the water heater installation yourself.



Safety First

The danger of working with electricity, gas and hot water cannot be overstated. Unless you're absolutely certain you're up to the task, let a professional do the job.



Have The Right Tools 

One sure sign you need professional water heater installation is not having — or even knowing! — the essential tools necessary for the task. Line out all your tools so they're easy to access during your DIY water heater installation, and don't be afraid to contact a pro if you get stuck.



Check The Specs (Electrical Specs and Dimensions)

Knowing the water heater capacity you need isn't enough — you also need to know if your home's electrical system can power the water heater. Also, check the measurements for the water heater installation area when you're picking out a unit to ensure the unit fits your space. Refer to the installation instructions when installing a water heater or consult a professional installer

How To Install an Electric Hot Water Heater

two people handling equipment


This step-by-step is a basic guide that walks you through electric water heater installation. Follow each step correctly and mindfully to ensure a safe setup. Always refer to the installation manual provided with a water heater. These instructions do not replace the printed instructions that come with the water heater or professional installation


Removing The Old System

Remove your old hot water heater installation with this step-by-step guide.


Step 1: Turn Off the Associated Breaker

First, turn off the breaker associated with your old water heater or remove its fuses. Open the access panel on your old water heater to get to the electrical junction box, then use the noncontact circuit tester to ensure the unit is powered down.


Step 2: Run the Hot Water Until Cool

Before you drain your old unit, open a hot water faucet and let it flow until the water runs cool. This typically takes 10-plus minutes, but it's a necessary step to prevent scalding.

turning the cold water off

This image is only being used as example and may not reflect the specific unit or part that you may be troubleshooting.

Step 3: Shut Off the Water Supply

Since you don't want the tank to refill again before you drain it, shut off the water supply to the water heater. Also, turn off the unit's cold water supply.


Step 4: Disconnect Electrical Supply

Locate the wire nuts that connect the appliance service wire to your home's power wires, then unscrew them. Next, find the water heater's green ground screw and disconnect the ground wire. Lastly, remove the electric cable, disconnect the strain relief and use wire nuts to cap off your home's power wires.


Step 5: Drain the Tank

Connect a garden hose to the drain valve on your water heater, take the other end outside or put it in a sink, tub or bucket, then open the water heater's drain valve. Help this process along by turning on a hot water faucet for faster water heater drainage. Sediment buildup in the bottom of the tank sometimes prevents proper drainage, and in instances when tanks don't completely drain, you may need professional help. (Learn more about How to Drain a Water Heater)

handling equipment

This image is only being used as example and may not reflect the specific unit or part that you may be troubleshooting.

Step 6: Remove the T&P Valve and Discharge Pipe

Next, disconnect the temperature and pressure (T&P) relief valve and discharge pipe. If it's in good shape, you can salvage the discharge pipe for your new water heater installation but never reuse a T&P relief valve. Your new water heater, however, should come with a new one. 


Step 7: Disconnect the Water Lines

Disconnect both water lines by using a wrench. If you have compression fittings, cut them close to the water heater so you can easily connect them to your new unit. (Read more about How to Light a Pilot Light)


Step 8: Remove and Dispose of the Old Heater

Once everything's disconnected, pull in the hand truck or appliance dolly to remove your old water heater. These units are usually heavy, so be sure you have someone else there to help you.

Plumbing Professional

Find A Local Water Heater Pro

A. O. Smith water heaters are professionally installed by local independent contractors.

How to Uninstall a Gas Water Heater

removing equipment

This image is only being used as example and may not reflect the specific unit or part that you may be troubleshooting.

Gas water heater installation often proves more complex than electric water heater installation — and more dangerous! This is because you're working with gas lines, and only experienced professionals can do this safely. If you want to DIY the process, though, these steps can help you. Always refer to the printed instructions when installing a water heater or hire a professional installer. This is a basic guide and not a replacement for the printed instructions included with the water heater or professional installation.



Removing The Old System

Use these steps to remove your old system before the new hot water heater installation.

turning the gas off

This image is only being used as example and may not reflect the specific unit or part that you may be troubleshooting.

Step 1: Run Water Until It's Cool

Drain the tank of all hot water by turning on a hot water tap. This takes approximately 10 minutes, but it reduces risks of scalding.


Step 2: Turn Off the Water Heater and the Gas

Turn off your water heater via the gas control valve, then turn off the main gas supply valve. Next, break the union between the gas lines with two wrenches, then cap the gas line and remove the gas pipe from the control valve on your water heater.


Step 3: Shut Off the Water Supply

Turn off the hot and cold water supply lines to your water heater, then connect a garden hose to your drain valve and take it outside, put it in a bucket or place it in a sink or tub.

person draining valve

This image is only being used as example and may not reflect the specific unit or part that you may be troubleshooting.

Step 4: Drain the Tank, Then Disconnect Water and Gas Lines

Ensure the hose is secure on the drain valve, then turn it on to let all the water flow out of your water heater. For faster drainage, turn on a hot water tap inside your home. Next, disconnect water and gas lines with a wrench.


Step 5: Detach the Gas Exhaust, Then Remove and Dispose of the Old Heater

Let the gas exhaust pipe that vents the hot water heater cool down, then remove it from the draft hood. If necessary, prop or tie this pipe up to keep it in place for your new water heater installation. Place the old water heater on a hand truck or dolly, then remove it for proper disposal.

Plumbing Professional

Find A Local Water Heater Pro

A. O. Smith water heaters are professionally installed by local independent contractors.

Installing a Gas Water Heater

Installing the Metal Drain Pan

This image is only being used as example and may not reflect the specific unit or part that you may be troubleshooting.

Use this guide to install your new hot water heater. If you're unsure about working with gas, consult a professional who understands the complexities involved.


Step 1: Place and Level Water Heater

Install a metal drain pan that's at least 2 inches in diameter wider than your unit and no deeper than 1.75 inches. Place the water heater in the drain pan so you have ample room to examine beneath it as needed. 


Step 2: Install Heat Trap Fittings and Connect Water Lines

Put all the heat trap fittings into place on the new water heater, then connect both the hot and cold water lines with 3/4-inch NPT threaded adapters. 

handling equipment

This image is only being used as example and may not reflect the specific unit or part that you may be troubleshooting.

Step 3: Install the Pressure Release Valve Discharge Line

Install a discharge pipe with 3/4-inch interior diameter, sloping it downward so it drains properly. End this pipe between 1 and 6 inches from a drain or an outside destination.


Step 4: Connect the Gas Supply Lines

Installation kits may come with flexible gas connectors. Use these to hook up gas lines to your water heater following the manufacturer's instructions. If you're unsure about working with gas lines, a professional installer may be your best bet.


Step 5: Turn On the Water, Fill Up the Tank, Purge Air and Check for Leaks

Fill up the tank to the top, then remove the aerator from the closest hot water tap and turn it on full blast. Let the water flow for 3 minutes to purge all air from the tank, and check the water connectors for any leaks while you wait. 


checking equipment

Step 6: Turn on the Gas and Carefully Check Fittings for Leaks

If everything looks good, turn the gas back on and check all the fittings for leaks. Do this by applying dish soap or bubble solution, then looking for bubbling at the connectors.


Step 7: Ignite the Pilot Light Using the Control Knob or a Small Flame

Turn the gas supply on, then use the control knob or a small flame to ignite the pilot light. When it's lit, the status light on your water heater should start blinking. Adjust the thermostat temperatures at this point and add tank insulation for energy efficiency and freeze prevention.


Find a Professional Installer Near You

Water heater installation may seem simple, but it can turn into a complex job if you don't have experience. You can ensure the process goes smoothly by choosing a local professional for water heater installation.


Get help with repairs, maintenance and full water heater replacements from a professional plumbing contractor near you.

Plumbing Professional

Find A Local Water Heater Pro

A. O. Smith water heaters are professionally installed by local independent contractors.

Why A. O. Smith?

 
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Market Leader

A. O. Smith is a leading manufacturer of both residential and commercial water heating technologies, including the #1 most specified commercial water heater.

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Commitment to Innovation

For more than 145 years, we’ve developed state-of-the art products that push new boundaries and improve the lives of our customers.

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Best-In-Class Support

We combine cutting-edge technology with committed people who take pride in providing the very best support for our customers.

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Unmatched Quality

Our products are put through rigorous quality and endurance testing so now matter where hot water is needed, A. O. Smith can provide a solution you can count on.

Learn more about A. O. Smith