Electrical - Lennox ML180UHA Installation Instructions Manual

Leak Check
After gas piping is completed, carefully check all piping
connections (factory- and field-installed) for gas leaks. Use
a leak detecting solution or other preferred means.
NOTE - If emergency shutoff is necessary, shut off the main
manual gas valve and disconnect the main power to the
furnace. The installer should properly label these devices.
CAUTION
Some soaps used for leak detection are corrosive to
certain metals. Carefully rinse piping thoroughly af­
ter leak test has been completed. Do not use
matches, candles, flame or other sources of ignition
to check for gas leaks.
The furnace must be isolated by closing its individual man­
ual shut‐off valve and disconnecting from from the gas sup­
ply system the during any pressure testing of the gas sup­
ply system at pressures greater than 3.48 kPa (1/2 psig, 14
inches w.c.).
IMPORTANT
When testing pressure of gas lines, gas valve must
be disconnected and isolated. See figure 24. Gas
valves can be damaged if subjected to pressures
greater than 1/2 psig (3.48 kPa, 14 inches w.c.).
MANUAL MAIN
SHUT-OFF VALVE
WILL NOT HOLD
NORMAL TEST
PRESSURE
1/8 NPT PLUG
CAP
FIGURE 24

Electrical

CAUTION
Electrostatic discharge can affect elec­
tronic components. Take precautions
to neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
A power wiring harness is shipped with each ML180UHA
furnace. An IEC receptacle is provided on the right side of
the unit. Plug the harness into the IEC receptacle and into a
properly sized wall plug.
Refer to figure 26 schematic wiring diagram.
1 - Ensure that power connection point is located with 2m
of furnace.
ISOLATE
GAS VALVE
FURNACE
2 - Holes are on both sides of the furnace cabinet to facili­
tate thermostat wiring.
3 - Before connecting the thermostat wiring, check to
make sure the wires will be long enough for servicing at
a later date. Remove the blower access panel to check
the length of the wire.
4 - Complete the wiring connections to the equipment.
Use the provided unit wiring diagram shown in figure
26. 18-gauge wire or larger that is suitable for Class II
rating for thermostat connections.
5 - Electrically ground the unit according to local codes.
NOTE - The ML180UHA furnace contains electronic
components that are polarity sensitive. Make sure that
the furnace is wired correctly and is properly grounded.
6 - One line voltage "EAC" spade terminal is provided on
the furnace control board. Any electronic air cleaner
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 25 for
control board configuration. This terminal is energized
when the indoor blower is operating.
7 - One line voltage "HUM" spade terminal is provided on
the furnace control board. 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 25 for control
board configuration. This terminal is energized in the
heating mode when the combustion air inducer is oper­
ating.
8 - Install the room thermostat according to the instruc­
tions provided with the thermostat. See figure 26 for
thermostat designations. If the furnace is being
matched with a heat pump, refer to the instruction
packaged with the dual fuel thermostat.
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 ML180UHA 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.
Generator Use - Voltage Requirements
The following requirements must be kept in mind when
specifying a generator for use with this equipment:
S
The furnace requires 240 volts + 10%.
S
The furnace operates at 50 Hz + 5% .
S
The furnace integrated control requires both polarity
and proper ground. Both polarity and proper grounding
should be checked before attempting to operate the
furnace on either permanent or temporary power.
S
Generator should have a wave form distortion of less
than 5% THD (total harmonic distortion)
Page 16