Lennox MERIT Series Installation Instructions Manual page 36

Refer to figure 53 for field wiring, schematic wiring dia-
gram and troubleshooting.
The power supply wiring must meet Class I restrictions.
Protected by either a fuse or circuit breaker, select circuit
protection and wire size according to unit nameplate.
NOTE - Unit nameplate states maximum current draw.
Maximum Over-Current Protection allowed is 15 AMP.
Holes are on both sides of the furnace cabinet to facilitate
wiring.
Install a separate (properly sized) disconnect switch near
the furnace so that power can be turned off for servicing.
Before connecting the thermostat check to make sure
the wires will be long enough for servicing at a later date.
Make sure that thermostat wire is long enough to facilitate
future removal of blower for service.
Complete the wiring connections to the equipment. Use
the provided unit wiring diagram and the field wiring dia-
gram shown in figure 53. Use 18-gauge wire or larger that
is suitable for Class II rating for thermostat connections.
Electrically ground the unit according to local codes or,
in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No. 70) for the USA
and current Canadian Electric Code part 1 (CSA standard
C22.1) for Canada. A green ground wire is provided in the
field make-up box.
NOTE - The ML195DF furnace contains electronic com-
ponents that are polarity sensitive. Make sure that the fur-
nace is wired correctly and is properly grounded.
Accessory Terminals
One line voltage "EAC" 1/4" spade terminal is provided on
the furnace integrated control. See figure 54 for integrated
control configuration. This terminal is energized when the
indoor blower is operating. Any accessory 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 neu-
tral terminals. If an accessory rated at greater than one
amp is connected to this terminal, it is necessary to use
an external relay.
One line voltage "HUM" 1/4" spade terminal is provided on
the furnace integrated control. See figure 54 for integrat-
ed control configuration. This terminal is energized in the
heating mode when the combustion air inducer is operat-
ing. Any humidifier rated up to one amp can be connect-
ed to this terminal with the neutral leg of the circuit being
connected to one of the provided neutral terminals. If a
humidifier rated at greater than one amp is connected to
this terminal, it is necessary to use an external relay relay
Indoor Blower Speeds
1 - When the thermostat is set to "FAN ON," the indoor
blower will run continuously on the heating speed
when there is no cooling or heating demand.
2 - When the ML195DF is running in the heating mode,
the indoor blower will run on the heating speed.
3 - When there is a cooling demand, the indoor blower
will run on the cooling speed.
Thermostat
Install the room thermostat according to the instructions
provided with the thermostat. See figure 54 for thermostat
designations. If the furnace is being matched with a heat
pump, refer to the FM21 installation instruction or appro-
priate dual fuel thermostat instructions.
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 + 10% (Range: 108
volts to 132 volts)
• The furnace operates at 60 Hz + 5% (Range: 57 Hz
to 63 Hz)
• The furnace integrated control requires both po-
larity 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).
Page 36