Plan the System

• 1). Evaluate your hot water system. If your hot water heater is below most of the faucets that use hot water, you can use gravity to move the hot water in the circulation system. If you have hot water lines that go below the hot water heater, you need to use a recirculation pump.
  
  
• 2). Look at the existing hot water piping. These pipes make up half of your recirculation system. You need to tap into these pipes near the fixtures to make the return loop to the hot water heater. The return loop pipes need to be installed away from the floor joists to prevent crushing the insulation.
  
  
• 3). Determine where you will tap into the existing hot water system, and where you can install the return loop piping in between floor joists.
  
  

Rough-in the System

• 1). Turn off the water to your house to prevent water leakage. Locate the main hot water line that travels from the hot water heater to the furthest fixture. Cut into this line as close to the fixture as you can get with pipe cutters.
  
  
• 2). Install a tee fitting onto the main hot water pipe. Place the return loop piping into the corner section of the tee fitting. Run the hot water pipe down along the main hot water supply until you reach the first tee-off to the next fitting. Connect it to the ceiling with pipe hangers.
  
  
• 3). Install insulation either onto the pipe before you put it up, or after you put it up, depending on the insulation type. Do not insulate the entire return loop or it will not allow the water to circulate.
  
  
• 4). Go to the next fixture and cut into the hot water pipe and install a tee fitting. Place a hot water pipe into the corner section of the tee, and run it down to where the main loop line is located. Install another tee fitting and connect this pipe to the main loop.
  
  
• 5). Repeat with each fixture, connecting the return loop to the main hot water line, and the return loop to the main return loop line with tee fittings.
  
  
• 6). Run the return loop pipe to the bottom of the hot water heater at the drain valve. Remove the drain valve with a wrench and install an insulated nipple. Install a tee fitting with female threads at the tee section. Replace the drain valve onto the threads.
  
  
• 7). Install a check valve onto the return loop if you use a gravity system to prevent cold water from running back into the return loop, or a recirculating water pump if you are using a pump. Install the return loop to the check valve or water pump.