Lennox SL280UHNV Installation Instructions Manual page 22

8 - 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.
9 - Install the room thermostat according to the
instructions provided with the thermostat. See table
8 for field wiring connections in varying applications.
If the furnace is being matched with a heat pump,
refer to the instruction packaged with the dual fuel
thermostat.
Thermostat Selection
NOTICE
Field wiring for both
communicating applications is illustrated in diagrams,
which begin on the next page.
Non-Communicating
In non-communicating applications the SL280UHNV is
designed to operate in a SINGLE-STAGE mode or TWO-
STAGE mode using a conventional thermostat.
For optimal performance in non-communicating appli-
cations, Lennox recommends use of a ComfortSense®
7000 igh quality electronic digital thermostat or any other
with adjustable settings for 1st stage / 2nd stage on / off
differentials and adjustable stage timers.
Lennox recommends the following two-stage thermostat
settings:
First heat stage differential set to 1/2 to 1 degree F; sec-
ond heat stage differential set to 1/2 or 1 degree F; second
heat stage upstage timer disabled, or set to maximum (1
hr minimum).
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 com-
munication terminal strip. (RSBus). Using an additional
wire come off "C" terminal and wire nut all the extra wires
together. Termination on the outdoor control must match
the indoor control.
communicating and non-
Indoor Blower Speeds
Non-Communicating
1 - 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. See Table 21
for allowable circulation speeds.
2 - When the SL280UHNV 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. First stage heating will run at 91%
heat speed.
3 - 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 SL280UHNV is used with a communi-
cating thermostat, proper indoor blower speed selections
are made by the thermostat.
1 - When the thermostat is set to "FAN ON," the indoor
blower will run at setting determined during system
configuration. See Table 21 for allowable circulation
speeds.
2 - When there is a heating demand the fan will run on
heating speeds for firing rate.
3 - 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 oper-
ate the furnace on either permanent or temporary power
• Generator should have a wave form distortion of less
than 5% THD (total harmonic distortion)
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