How to Install a Water Heater Circulating Pump
A hot water recirculating pump keeps hot water moving through your pipes so it reaches your faucet faster. Turn on the tap and hot water arrives in seconds. Installing a water heater circulating pump takes professional expertise. Licensed plumbers handle the electrical work, plumbing changes, and code requirements to get your system running safely. If it requires hardwiring, an electrician is needed.
Find a certified installer in your area who can assess your home's plumbing and complete the installation.
What Is a Hot Water Recirculating Pump?
When water sits in your hot water pipes overnight, it cools down. The next time you need hot water, cold water runs from the tap until fresh hot water travels from your water heater to the fixture. A recirculating pump pushes water from your water heater through the hot water pipes and back again in a continuous loop.
On-demand systems activate when you press a switch, trigger a sensor, or use a timer, then run until the water temperature rises 10 degrees or reaches 102 degrees Fahrenheit (depending on your system's control method).
Manual controls include wired or wireless switches placed near fixtures. Automatic options, such as motion detectors and door sensors, can start the pump when you enter a room. A timer can also be used to start the pump at specific times throughout the day.
Learn about the cost of heat pump water heaters and cost savings, including federal rebates up to $2,000 that can make energy-efficient upgrades more affordable.
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Benefits of Recirculation Systems
Hot water recirculation pumps solve the wait time problem while reducing water use and energy costs:
- Water Conservation: Cold water that normally runs down the drain while you wait stays in your pipes, reducing household water consumption.
- Lower Energy Bills: On-demand systems with temperature controls run only when needed.
- Faster Hot Water Delivery: Hot water reaches your fixtures in seconds, speeding up showers and kitchen tasks.
Plumbing Requirements for Recirculation Systems
Hot water recirculation systems work with three different plumbing setups depending on your home's existing pipes:
Dedicated Return Line Systems
A separate pipe carries water back to your water heater. You can install the recirculating pump and temperature sensor at the end of the hot water supply line, typically under a fixture. If the pump goes on the return line near the water heater instead, place the temperature sensor as close to the furthest fixture as possible. Hot water flows out through one pipe while cooled water returns through the dedicated line.
Cold Water Line Return Systems
Homes without a dedicated return line use the existing cold water line as the return path. Install the circulating pump and temperature sensor at the end of the hot water line.
A crossover valve lets water flow back through the cold water pipe to the heater. This setup works with your existing plumbing without adding new pipes.
Temperature Sensor Placement
The temperature sensor location depends on your plumbing setup. For homes with a dedicated return line, the sensor typically goes at the end of the hot water supply line near the furthest fixture. If your home uses the cold water line as a return path, the sensor goes at the end of the hot water distribution line. Your plumber will position the sensor correctly based on which configuration works with your existing plumbing.
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Rebates & Tax Credits
Rebate and incentive programs provide savings to consumers for the purchase of water heaters that meet certain energy efficiency standards.
Need Help From A Pro?
A. O. Smith water heaters are professionally installed by local independent contractors.
Working with a Licensed Plumber
A hot water recirculation pump requires electrical connections, plumbing modifications, and meeting local building codes that vary by location.
Choosing the Right Pump
Your plumber picks a pump based on how far water travels from your water heater to the furthest fixture, whether you have a dedicated return line, and how much hot water your household uses daily. The wrong size pump either can't keep up with demand or runs more than necessary.
Temperature Controls
The pump activates when you press a switch or trigger a sensor like a motion detector or door switch. It shuts off using one of two control methods: either when the water temperature rises up to 10 degrees above the starting temperature, or when it reaches a maximum of 102 degrees. Your plumber configures which method your system uses during installation. A backup timer stops the pump after five minutes if the temperature controls malfunction.
Electrical and Permit Work
Circulating pumps run on dedicated electrical circuits. Your plumber wires the connections, gets the permits, and schedules inspections. Shut-off valves and check valves go in during installation. In some cases, an electrician will be needed for the electrical connections.
Pipe Insulation
All hot water pipes need insulation with a one-inch wall thickness or an R-value of 7.7, including the return line. Without it, heat escapes as water moves through the pipes.
Using Recirculation with Heat Pumps
Heat pump water heaters pull heat from the air and transfer it to the water. Adding a recirculation system increases demand on the water heater. Without proper controls, the heat pump runs longer or continuously, reducing available hot water. Your plumber sizes the pump correctly and programs the temperature controls to work with your heat pump.
What to Expect During Installation
Licensed plumbers follow a standard process for installing recirculation systems.
Initial Assessment
Your plumber examines your plumbing system and electrical setup, then explains whether your home needs a dedicated return line or can use the existing cold water line. They provide a cost estimate that includes labor, materials, permits, and electrical work.
Installation Process
Your plumber handles all the physical work to get the system running. This includes:
- Circulating Pump: Goes at the end of the hot water line or on the return line near the heater.
- Temperature Sensor: Gets placed near the furthest fixture from the heater.
- Activation Controls: Switches or sensors go in at the fixtures you use most.
- Valves: Shut-off and check valves control the water flow through the system.
- Crossover Valve: Added at the furthest fixture if your home uses the cold water line as a return path.
Testing the System After Installation
Your plumber tests the water temperature at each fixture and programs the temperature controls. They adjust the system as needed to make sure hot water reaches every tap. Then the plumber walks you through the controls and explains how to operate the system.
Rebates & Tax Credits
Rebate and incentive programs provide savings to consumers for the purchase of water heaters that meet certain energy efficiency standards.
Need Help From A Pro?
A. O. Smith water heaters are professionally installed by local independent contractors.
Work with A. O. Smith Installers
A. O. Smith has been making water heaters for over 85 years. Our network of certified contractors receives direct training on our equipment and stays current with installation requirements and local codes.
Find a certified installer in your area who can assess your home and who knows how to install a water heater circulating pump properly. Contractors can access training through A. O. Smith University, which offers instruction on installation techniques and product specifications.
Frequently Asked Questions
Most homeowners shouldn't install a water heater circulating pump without professional help. The work requires electrical connections, plumbing modifications, and programming temperature controls that meet local codes.
Installation time depends on your plumbing setup. Homes with existing compatible plumbing take a few hours, while homes needing modifications take longer.