How to Install a Water Tempering Tank

A tempering tank preheats cold water to room temperature or higher.

A tempering tank is an un-insulated water tank located in a warm area of the home, like an attic, which is connected in series with the existing hot water tank. Cold water entering the tempering tank is warmed to room temperature or higher before reaching the main hot water tank. By receiving temperate water in this manner, the hot water tank utilizes less power to heat up the water that it contains.

Things You'll Need

• 10 feet of copper tubing, 0.75-inch diameter
• Temperature and pressure relief valve (optional)
• Shifting spanner
• Copper tubing cutter
• Gloves (optional)

Instructions

1. Turn off the power to the existing hot water tank.

2. Turn off the cold water supply to the existing hot water tank. Ensure the tap is tightly closed.

3. Drain the hot water tank partially by opening taps over the sink or bath.

4. Disconnect from the hot water tank the copper pipe that feeds the cold water supply to the hot water tank.

5. Position the tempering tank in the warmest area of the attic.

6. Run the cold water supply to the tempering tank.

7. Connect the original cold water supply to the inlet of the tempering tank.

8. Verify that the inlet pipe of the cold water supply extends into the water in the tempering tank.

9. Remove the existing temperature and pressure relief valve on the warm water tank and discard. This step is optional, as a number of people find it easier to reconnect the copper pipes, when working with a new valve. It also negates the need to replace a faulty valve at a later stage.

10. Install a new temperature and pressure relief valve in the hot water tank. Ensure that the sensing element of the temperature and pressure relief valve is immersed in water in the hot water tank to a depth of at least 6 inches.

11. Connect the copper pipe from the tempering tank to this valve. The cold water supply was originally connected to this valve.

12. Turn on the cold water supply and fill both the tempering tank and the hot water tank.

13. Allow water in the tempering tank to warm up over a twenty-four hour period.

14. Turn on the power to the hot water tank. Allow the tank time to heat up and operate as per the instruction manual.

References

• Home Energy: Water Heaters and Energy Conservation -- Choices, Choices!
• Meyermfg: Installation Instructions

Resources

• Inspection Protection: Water Heaters