Page 32
An unpowered, normally open (dry) set of contacts with
a 1/4” spade terminal “HUM” are provided for humidifier
connections and may be connected to 24V or 120V. Any
humidifier rated up to one amp can be connected to these
terminals. In 120V humidifier applications the neutral leg of
the circuit can be connected to one of the provided neutral
terminals. This terminal is energized in the heating mode.
Install the room thermostat according to the instructions
provided with the thermostat. See table 11 for field wiring
connections in varying applications. If the furnace is being
matched with a heat pump, refer to the instruction pack-
aged with the dual fuel thermostat.
Thermostat Selection
CAUTION
Field wiring for both communicating and non-
communicating applications is illustrated in diagrams,
which begin on Page 34.
Non-Communicating
In non-communicating applications the SL297UHNV
is designed to operate in a SINGLE-STAGE mode or
TWOSTAGE mode using a conventional thermostat.
For optimal performance in non-communicating applica-
tions, Lennox recommends use of a conventional high
quality electronic digital thermostat or any other with ad-
justable settings for 1st stage / 2nd stage on / off differen
-
tials and adjustable stage timers.
Communicating
In communicating applications a communicating thermo-
stat must be used. Refer to the instructions provided with
the thermostat for installation, set-up and operation. In
communicating system all unused thermostat wire in the
wire bundle needs to be terminated inside and out. The
extra wires can terminate on the ‘C” terminal of the termi-
nal strip. (RSBus). Using an additional wire come off ”C”
terminal and wire nut all the extra wires together. Termina-
tion on the outdoor control must match the indoor control.
Indoor Blower Speeds
Non-Communicating
When the thermostat is set to “FAN ON,” the indoor blower
will run continuously at a field selectable percentage of
the second-stage cooling speed when there is no cooling
or heating demand. The factory default setting is 38% of
cool speed.
When the SL297UHNV is running in the heating mode,
the indoor blower will run on the heating speed designated
by the positions of DIP switches 11, 12 and 13. When
there is a cooling demand, the indoor blower will run on the
cooling speed designated by the positions of DIP switches
5 and 6. First stage cooling will run at 70% cool speed.
Communicating
NOTE -
When the SL297UHNV is used with a communi
-
cating thermostat, proper indoor blower speed selections
are made by the thermostat.
When the thermostat is set to “FAN ON,” the indoor blow-
er will run at setting determined during system configura
-
tion. See TABLE 24 on page 66 for allowable circulation
speeds.
When there is a heating demand the fan will run on heat-
ing speeds for firing rate. See TABLE 23 on page 66 for
allowable heating speeds.
When there is a cooling demand, the fan will run on the
first stage and second stage cooling speed set using the
thermostat in the installer setup mode. The factory default
is based upon 400 CFM a ton.
Generator Use - Voltage Requirements
The following requirements must be kept in mind when
specifying a generator for use with this equipment:
• The furnace requires 120 volts (Range: 102 volts to
132 volts)
• The furnace operates at 60 Hz + 5% (Range: 57
Hz to 63 Hz)
• The furnace integrated control requires both correct
polarity and proper ground. Both polarity and proper
grounding should be checked before attempting to
operate the furnace on either permanent or tempo-
rary power
• Generator should have a wave form distortion of
less than 5% THD (total harmonic distortion)
Summary of Contents for DAVE LENNOX SIGNATURE SL297UHNV
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