SECTION V: OPERATION
Following adjustment of the setpoint to a higher temperature (see Figure 36), the main burner
should relight. Next, adjust the setpoint to a lower temperature (i.e. back to 120° F) and the
gas valve will close, extinguishing the burner flame. The thermostat should be adjusted to the
minimum setting that will meet the hot water needs of the application.
CAUTION
There is a scald potential if the thermostat is set too high. The recommended
temperature setting for normal residential use is 120°F. If higher temperature settings
are needed for combined appliance applications or commercial use, an automatic
tempering valve must be installed on all domestic hot water lines.
MEASURING THE POINT-OF-USE WATER TEMPERATURE
The thermostat is factory set at 120°F for domestic use. It is the responsibility of the building
owner to verify that the installer follows the recommended quantitative testing for measuring
the point-of-use water temperature. To make sure that the system works properly after instal-
lation and in the future, it is recommended that the heater’s performance be measured and
monitored. Run water out of a faucet nearest the heater until it comes out warm. Using a
calibrated thermometer, take a measurement. If the water is not at a suitable temperature for
the application, adjust the setting on the control or the tempering valve.
This log (or a similar one) should be filled out as follows:
Page 45
Date
Time
Person running test
Setpoint Temperature °F
Faucet Temperature °F
