Bradford White UCG100H199 Installation & Operation Manual page 28

Hotter water increases the risk of scald injury. Scalding may occur within five (5) seconds at a temperature setting

of 140F (60 C). To protect against hot water injury, install an ASSE approved mixing valve in the water system.
This valve will reduce point of discharge temperature by mixing cold and hot water in branch water lines. A licensed
plumbing professional or local plumbing authority should be consulted.
This water heater is equipped with an energy cut out device to prevent overheating. Should overheating occur or
the gas supply fail to shut off, turn off the manual gas control valve to the appliance and call a qualified service
technician.
This water heater, when set at a lower temperature setting, is not capable of producing hot water of sufficient
temperature for sanitizing purposes.
The lower the temperature setting, the greater the energy efficiency, both to heat the water and to maintain the
storage temperature during standby periods. Lower water temperatures also extend tank life. Remember, no water
heating system will provide exact temperatures at all times. Allow a few days of operation at this setting to
determine the correct temperature setting consistent with the requirements for the installation.
Condensation does not mean your tank is leaking. Over 40% of reported tank leaks on installation are proven to be
condensation. To avoid unnecessary expense and inconvenience, make sure the tank is leaking before calling a
service person.
Combustion Air/Gas Ratio: Efficiency
This water heater is factory equipped with a Honeywell gas valve/air mixing venturi system designed and set to
maintain appropriate combustion excess air level (air/gas ratio) under normal operating conditions. The water
heater excess air level is field adjustable in order to optimize water heater efficiency. When the excess air level is
adjusted, an accurate and recently calibrated combustion gas analyzer, which correctly measures carbon monoxide
(CO) and carbon dioxide (CO2) levels in the exhaust gas, as well as an accurate gas pressure manometer, are
mandatory. Carbon dioxide levels in the exhaust gas greater than 11.5% provide high efficiency. Carbon Monoxide
levels increase with increasing CO2 levels. Only individuals, installers or service technicians properly trained,
qualified and experienced with adjusting the Honeywell gas/air mixing venturi system, and with access to accurate
equipment, should attempt to adjust the air/gas ratio. See service manual for instructions.
DO NOT adjust the air/gas ratio unless you are qualified, experienced and properly trained in the Honeywell gas
valve/air mixing venturi system air/gas ratio adjustment process and are using accurate, certified CO2, CO and gas
pressure measurement equipment.
If the factory set air/gas ratio is changed, the exhaust gas concentration of CO2 and CO and the gas control gas
pressure MUST be monitored and properly adjusted no less than every 6 months thereafter.
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