Lennox MERIT Series Installation Instructions Manual page 36

One line voltage "HUM" 1/4" spade terminal is provided on
the furnace integrated control. Any humidifier rated up to
one amp can be connected to this terminal with the neutral
leg of the circuit being connected to one of the provided
neutral terminals. See FIGURE 55 for control configura-
tion. This terminal is energized in the heating mode when-
ever the combustion air inducer is operating.
Install the room thermostat according to the instructions
provided with the thermostat. If the furnace is being
matched with a heat pump, refer to the instruction pack-
aged with the dual fuel thermostat.
Indoor Blower Speeds
When the thermostat is set to "FAN ON," the indoor blower
will run continuously at approximately 38% of the second
stage cooling speed when there is no cooling or heating
demand.
When the unit is running in the heating mode, the indoor
blower will run on the heating speed designated by the
positions of DIP switches (A, B, C, D) of the HEAT jumper.
See FIGURE 52. See Allowable heating speeds table on
page 39.
When the unit is running in the cooling mode, the indoor
blower will run on the cooling speed designated by the
positions of DIP switches (A, B, C, D) of the COOL jumper.
See FIGURE 52.
Adjust HEAT and COOL Taps on the
integrated Control
FIGURE 52
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)
Electrical Wiring
The furnace must be grounded and wired in accordance
with local codes or, in the absence of local codes, with the
National Electrical Code ANSI/NFPA No. 70 (latest edi-
tion) and/or CSA C22.1 Electrical Code (latest edition) if
an external electrical source is utilized.
In all instances, other than wiring for the thermostat, the
wiring to be done and any replacement of wire shall con-
form with the temperature limitation for Type T wire –635F
(355C) rise.
Connect a sufficiently sized wire with ground to the fur-
nace's line voltage connections and ground wire. Refer
to the furnace rating plate for electrical characteristics to
be used in sizing field supply wiring and over current pro-
tection.
The line voltage supply should be routed through a readily
accessible disconnect located within sight of the furnace.
A junction box on the furnace side panel is provided for
line voltage connections. Refer to the furnace wiring dia-
gram for specific connection information.
Proper polarity of the supply connections ("HOT" and
"NEUTRAL") must be observed to ensure that safety
controls provide the protection intended.
A connection to the unit's ground wire and actual earth
ground (typically a ground stake or buried steel pipe) must
be maintained for proper operation.
Thermostat Selection
Install a room thermostat according to the instructions fur-
nished with it. Select a location on an inside wall that is
not subject to drafts, direct sunshine, or other heat sourc-
es. The initial heat anticipator setting should be equal to
the total current draw of the control circuit. Low voltage
thermostat connections are to be made to the integrated
ignition/ blower control board as indicated on the wiring
diagram.
Single Stage Thermostat Operation
The automatic heat staging option allows a single stage
thermostat to be used with two stage furnace models. To
activate this option, move the jumper pin (see Figure 58)
to desired setting (5 minutes or 10 minutes). The furnace
will start on 1st stage heat and stay at 1st stage heat for
the duration of the selected time before switching to 2nd
stage heat.
W1 on the integrated control must be connected to W1 on
the thermostat.
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