Using a Thermometer

• Follow the instructions for scheme 2. After about four hours, the temperature should be in the neighborhood of 115-120° F.
• If the thermometer has a MIN/MAX memory feature, reset it now.

• Fill a plastic or other insulating container with your hottest hot tap water.

• Measure the temperature of the water with the external probe of the thermometer. (Put the probe in a plastic bag to prevent water from entering the probe. You may need to weigh the bag down with a rock or something similar.)
• Read the MAX temperature on your thermometer.
• Adjust the thermostat on your hot water heater up or down as required to get it into the range of 115-120 degrees F. After about four hours, take another measurement and repeat as necessary.
  

Without a Thermometer

• Turn down the thermostat on your hot water heater until you can shower using no cold water.
• This should be about 115 degrees F.