LAARS U.H.E. - Installation Manual - Manual (Page 6)

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 Hot Surface Ignition System (HSI) then ignites the gas/air fuel mixture to produce flue products
(combustion). The flame sensor signals the ignition module (described below), that a flame is present.
IGNITION MODULE – The ignition module provides the timing for the combustion system. A sequence of operation
(S-OP) is described in “Section IX - Operating Instruction.” As the combustion system progresses through the S-OP,
LED’s illuminate, allowing accurate trouble-shooting should the need arise. If a failure occurs, the system will “blink”
the LED that corresponds to the failure as described in the “Section XI Troubleshooting Guide.”
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 80°F to about 180°F. The thermostat was adjusted to 120°F 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
needs. 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 will reduce the risk of scalds. Some states require setting the specific
lower temperatures.
The top immersion well of the single bulb controller also contains the high limit (energy cutoff) sensor. The high limit
switch interrupts the main burner gas flow should the water temperature reach approximately 200°F.
Should the high limit switch activate, it must be manually reset. This can be accomplished by turning the main power
on/off switch to the off position and then back to the on position and allowing the water temperature of the tank to drop
below 160°F.
Contact your qualified installing contractor, service provider or manufacturer listed on the rating plate if continued high
limit switch 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 differential pressure switch that monitors the
pressure across the exhaust orifice. 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.
LATCHES – The latches allow easy access for servicing the water heater from the top. Simply remove the two latches
for servicing and re-latch upon completion. No tools are required to obtain access to the top of the water heater.
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