TECHNICAL BULLETIN

The Engineering and Sciences Division of the United States Consumer Product Safety Commission has compiled the following time-temperature burn chart (based on the 1946 Harvard studies of Moritz and Henriques under Department of Defense contract). The chart shows the exposure times, under circumstances of full immersion, that will result in superficial, and partial or full-thickness, scald burns at various water temperatures. 

Please read all the steps of the test prior to beginning. If you feel uncomfortable performing any of these steps, contact a service person to conduct this test for you. 

STEP 1 - At the faucet nearest to the water heater, time (in seconds) how long it takes to fill a 1 gallon bucket (flow rate).

Gallon per minute (gpm) = 60 seconds / seconds to fill a 1 gallon bucket

If the bucket fills in:

• 10 sec = 6 gpm
• 12 sec = 5 gpm
• 15 sec = 4 gpm
• 20 sec = 3 gpm
• 24 sec = 2.5 gpm

STEP 2 - Turn thermostat dial on the water heater so the arrow points to “A” position.

STEP 3 - Run about 15 gallons of hot water from the nearest faucet. Shut water off.

STEP 4 - Water heater should complete heating 15 gallons in approximately 20-35 minutes.

STEP 5 - At a nearby faucet using a candy thermometer, measure the hot water temperature.

STEP 6 - The temperature should fall between 120°F to 140°F

STEP 7 - Continue running the hot water until 60% of the tank capacity is depleted:

CAPACITY vs DEPLETE

• 30 gallons - 18 gallons
• 40 gallons - 24 gallons
• 50 gallons - 30 gallons
• 75 gallons - 45 gallons
• 100 gallons - 60 gallons

STEP 8 - At the same faucet using a candy thermometer, measure the water temperature.

STEP 9 - The temperature should be about 30°F below the temperature in step 6.

Step 6 - if the temperature was not within range, check the thermostat.

Step 9 - if more than 30 °F was lost, check the dip tube.