Step-by-Step Guide to Installing a Tankless Water Heater

Installing a tankless water heater in your home is a great way to improve energy efficiency while ensuring you have a continuous supply of hot water whenever you need it. While the installation process may seem daunting, with proper preparation and a clear step-by-step guide, you can successfully install your own system or prepare the site for a professional installation. This guide will cover the installation process, from selecting the right unit to ensuring everything is functioning properly once the system is set up.

1. Choosing the Right Tankless Water Heater

Before you start the installation process, ensure you've chosen the right tankless water heater for your needs. Refer to the factors discussed in the previous article, such as hot water demand, flow rate, energy source (gas or electric), and required temperature rise. Selecting the right model based on these considerations is the first step to ensuring that the installation is successful and the system operates efficiently.

2. Gather Your Tools and Materials

Before beginning installation, gather all necessary tools and materials to ensure the process runs smoothly. The required tools will vary depending on the type of tankless water heater you're installing, but the following are the most commonly needed tools:

For Gas-Powered Tankless Water Heater:

• Pipe wrench or adjustable wrench
• Gas line fittings and flexible gas line
• Power drill with bits
• Venting materials (for exhaust pipes, vent caps)
• Pipe cutter and tubing
• Teflon tape for gas pipe connections
• Level and measuring tape

For Electric Tankless Water Heater:

• Phillips screwdriver and flathead screwdriver
• Electrical wiring tools (wire stripper, wire nuts, electrical tape)
• Circuit breaker for the electrical panel
• Drill and appropriate bits
• Level and measuring tape

Safety Gear:

• Safety goggles
• Work gloves
• Respirator (if needed for venting or insulation work)
• Fire extinguisher

3. Prepare the Installation Location

For Gas-Powered Units:

Gas-powered tankless water heaters require proper ventilation to expel exhaust gases safely. Ensure that you have a clear space for installing the venting system and that it is located near an exterior wall to facilitate the venting process.

• Venting : Gas units require direct venting (often a concentric vent pipe or double-walled venting pipe) to prevent carbon monoxide buildup. Follow local codes and the manufacturer's instructions for vent pipe size and placement.
• Clearance: Maintain the required clearance around the unit to allow for airflow and access to service ports.
• Gas Line : Ensure that your gas line is of the proper size to support the tankless heater's fuel demand. Depending on the unit's size, you may need to upgrade your gas line.

For Electric Units:

Electric units are more straightforward when it comes to installation, as they do not require venting. However, you will need to ensure that you have sufficient electrical capacity to support the unit.

• Electrical Panel : Verify that your home's electrical panel can handle the additional load. Electric tankless water heaters require a dedicated circuit with a sufficient amperage rating (typically 100-200 amps depending on the model).
• Clearance: Like gas models, electric units also require space around them for air circulation and maintenance access.

4. Shut Off Power and Water Supply

Before beginning any installation work, turn off the power supply to your water heater and shut off the water supply valve. If you're working with a gas-powered unit, also turn off the gas supply.

5. Install the Water Connections

Now that the preparation is done, it's time to hook up the water lines to your tankless water heater.

For Both Gas and Electric Models:

• Cold and Hot Water Inlets : Most tankless water heaters have color-coded connections for cold water (blue) and hot water (red). Attach the incoming cold water supply to the cold inlet and the hot water line to the hot outlet.
• Pipe Fittings : Use appropriate pipe fittings (e.g., copper, PEX, or PVC) and apply Teflon tape to all threaded connections to ensure a tight, leak-free seal.
• Pressure Relief Valve : Install the pressure relief valve according to the manufacturer's instructions. This valve is crucial for safety and must be connected to an appropriate discharge location.

6. Install the Gas Line (For Gas-Powered Units Only)

If you are installing a gas-powered tankless water heater, you will need to connect the unit to your home's gas supply.

• Pipe Installation : Use flexible gas lines to connect the unit to the gas supply pipe. Follow the manufacturer's instructions on pipe size, and be sure to use a pipe wrench to tighten connections securely.
• Leak Test : Once the gas line is connected, conduct a leak test by applying soapy water to the connections. If bubbles appear, there is a leak that must be addressed.
• Vent Installation : For gas models, install the venting system to expel exhaust gases safely outside. Follow local codes and the manufacturer's guidelines for vent pipe placement and vent cap installation.

7. Electrical Wiring (For Electric Units Only)

For electric units, wiring is one of the most critical aspects of the installation.

• Dedicated Circuit : Install a dedicated circuit in your electrical panel for the water heater. This circuit should be rated for the amperage specified by the manufacturer (usually 100-200 amps).
• Wire Size : Use the appropriate wire size for the amperage rating of the unit. Typically, for larger electric models, you may need to use 6 AWG to 8 AWG wire.
• Breaker Size : Ensure that the breaker size matches the unit's power requirements. This is crucial for safety and compliance with electrical codes.
• Connect Wires : Connect the incoming wires to the appropriate terminals on the tankless water heater. Secure the wires with wire nuts and electrical tape to prevent any accidental disconnections.

8. Test the Unit

With all the water, gas, and electrical connections made, it's time to test the unit.

• Turn on the Water : Open the water supply valves and check for leaks. If you notice any leaks, tighten the connections as needed.
• Turn on the Power : For electric models, turn on the circuit breaker and ensure the unit powers up. For gas models, turn on the gas supply and check the ignition system.
• Adjust Temperature Settings: Set the desired temperature on the unit. Most models will allow you to set the temperature digitally.
• Check for Proper Operation : Turn on the hot water faucet and check the water flow. Ensure that the unit is heating the water properly and that the temperature is consistent.

9. Final Inspection and Clean-Up

Once everything is functioning as expected, conduct a final inspection.

• Check the Venting System : Ensure that the venting system for gas units is secure and that no exhaust gases are leaking into the living space.
• Clear the Area: Clean up the installation area, remove any tools, and dispose of waste materials appropriately.
• Set a Maintenance Schedule : Schedule regular maintenance for your unit, such as descaling (for hard water areas) and filter replacements (if applicable).

10. Conclusion

Installing a tankless water heater can provide long-term energy savings and a continuous supply of hot water. While it involves a bit of technical work, by following this step-by-step guide, you can either tackle the installation yourself or prepare the area for professional installation. Whether you are installing a gas-powered or electric model, ensuring proper water, gas, and electrical connections is key to a successful installation.

As with any significant home improvement project, safety should always be your top priority. If you are unsure about any part of the installation process, it's always wise to consult a professional plumber or electrician. With the right preparation, your tankless water heater will provide efficient and reliable service for many years to come.