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SECTION III: GENERAL INFORMATION
FEATURES
This water heater contains the following features:
MAIN POWER ON/OFF SWITCH – The front panel of this water heater has a lighted ON/OFF switch, which is illuminated
when the main power is turned on to indicate power to the water heater.
COMBUSTION SYSTEM – This water heater is equipped with a self-compensating negative pressure pre-mix combustion
system. As the blower operates, air is drawn in through the air intake and into a venturi, which pulls gas from the gas valve. The
gas and air is then mixed in the combustion blower and sent through the transition tube into the burner. The Direct Spark Ignition
System (DSI) then ignites the gas/air fuel mixture to produce flue products (combustion). The flame sensor signals the ignition
control board (described below), that a flame is present.
HONEYWELL INTEGRATED CONTROL – Consists of a control board and a water heater display. An attractive digital water
heater display is on the top front of the water heater for precisely setting and displaying the temperature setpoint and monitoring the
status of the water heater. Pressing the temperature UP and DOWN buttons changes the temperature setpoint. The temperature
format may be displayed in degrees F or degrees C. The water heater display will show diagnostic codes in the event the water
heater needs servicing. The temperature readings of the tank sensor can be monitored in Service Mode. Also in Service Mode, the
display can show up to 10 previous error codes to further aid in servicing the water heater.
The single control board has plug in wiring harnesses to reduce the chance of miswiring. The control board controls all ignition,
temperature, and combustion blower functions. The control board controls the combustion blower, ignition timings, and gas valve
to control the combustion system in order to maintain the desired tank temperature. The sequence of operation is described in detail
in the Diagnostic Section at the back of this Installation and Operating Instruction Manual.
ADJUSTABLE THERMOSTAT – This water heater is equipped with an adjustable thermostat to control water temperature. Hot
water temperatures required for automatic dishwasher and laundry use can cause scald burns resulting in serious personal injury
and/or death.
The temperature may be adjusted from about 70°F (21°C) to about 180°F (82°C). The thermostat was adjusted to 70°F (21°C)
before the water heater was shipped from the factory. It is recommended that lower temperatures be used to avoid the risk of
scalding. Refer to the “Warnings” and the section on SCALDING in “Section V: Water Connections.” It is further recommended,
in all cases, that the water temperature be set for the lowest temperature, which satisfies your hot water requirements for the
installation. This will also provide the most energy efficient operation of the water heater and minimizes scale formation.
Setting the water heater temperature at 120°F (49°C) will reduce the risk of scalds. Some states require setting lower temperatures
for specific installations.
The top immersion well of the single sensor control also contains a redundant sensor for the high limit (energy cutoff). The high
limit circuit interrupts the main burner gas flow should the water temperature exceed approximately 200°F (93°C). Error code “65”
will be shown on the water heater control display if the high limit temperature has been exceeded.
Should the high limit switch activate, it must be manually reset. This should only be done by a service technician after the cause of
overheating has been corrected. Refer to the section on “Accessing Service Mode on the Display” in the Diagnostic section of this
Installation and Instruction Manual.
Contact your qualified installing contractor, service provider or manufacturer listed on the rating plate if continued high limit
operation occurs.
SERVICE PANEL – The service panel is located behind the service panel access cover, which is located by the exhaust elbow near
the bottom of the water heater. This panel contains a pressure switch that monitors the pressure in the exhaust pipe in case the vent
terminal becomes blocked. A collector high limit switch is used to monitor the ambient temperature between the first pass collector
and the exhaust collector. This is a manually re-settable switch. If this switch continues to trip, please contact an authorized service
agency.
