Lennox MCFA User manual

USER GUIDE
©2020 Lennox Industries Inc.
Dallas, Texas, USA
MCFA, MCFB, MMDA,
MMDB, MWMA, MWMB,
3WMB, M22A,
M33A and M33B
MINI-SPLIT SYSTEM INDOOR UNITS
507550-04
5/2020
Supersedes 8/2018
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause property damage, personal
injury or loss of life.
Installation and service must be performed by a licensed
professional HVAC installer (or equivalent) or a service
agency.
WARNING
ELECTRICAL SHOCK, FIRE, OR EXPLOSION
HAZARD.
DO NOT spray water on the indoor unit for any reason.
Do not touch the unit or the controller if your hands are
wet.
Do not insert your hands, tools or any other item into the
air intake or air outlet at either the indoor or outdoor unit.
Do not remove the outdoor unit fan guard for any reason.
CAUTION
If outdoor unit is installed on a raised stand, check
condition of stand occasionally to ensure that it remains
stable.
Do NOT install sprinklers or soaker hoses where they
can expose the outdoor unit to treated water. Prolonged
exposure to treated water will corrode the surface
of the steel and aluminum parts and will diminish the
performance of the unit.
IMPORTANT
System operation is controlled by either a wired or
wireless remote control. Refer to the manual provided
with the control for system operation.
To ensure comfort, make sure that temperature selection
has been properly set at the unit controller or wireless
remote control.
To ensure efcient operation, do not block air intake or
outlet at either the indoor or outdoor unit.
Do not stand on outdoor unit or store items on top of
unit.
Make sure that indoor unit directional louvers are
properly adjusted.
MCFA and MCFB Ceiling
or Floor-Mounted
Convertible
MMDA and MMDB Medium Static
Ducted
MWMA, MWMB and 3WMB Wall-
Mounted
M22A, M33A and M33B Cassette
THIS MANUAL MUST BE LEFT WITH THE
OWNER FOR FUTURE REFERENCE

2
Parts Arrangement
MMDA or MMDB
Medium-Static Concealed Duct Wall-Mounted Non-Ducted Unit
Cassette may be adjusted to provide discharge
air from one, two, three or four sides.
AIRFILTER
DIFFUSER LOUVER
ADJUSTMENT LEVER
Ceiling- or Floor-Mounted Non-Ducted Unit
DISCHARGE AIR LOUVER
AIRFILTER
RETURN AIR
DISCHARGE AIR LOUVER
AIRFILTER
(Open front cover)
RETURN AIR
(Filter)
CONTROL BOX
DISCHARGE AIR
BEHIND RETURN AIR GRILLE
RETURN AIR GRILLE
BEHIND RETURN AIR GRILLE
RETURN AIR GRILLE
M22A, M33A or M33B Cassette MCFA or MCFB
MWMA, MWMB or 3WMB
Figure 1. Parts Arrangement

3
Louver Adjustment
IMPORTANT
DO NOT adjust the louvers by hand. Louvers are
adjustable only by using the wired controller or wireless
remote control.
M22A, M33A or M33B Ceiling-Mounted Cassettes
Use the wired or wireless remote control to set the position
of the discharge air louvers. The louvers may be set to
automatically swing. The horizontal louvers will swing
outward to downward. You may also set the louvers so
that they are stationary in a single position. It is always
recommended to direct the horizontal discharge air louvers
downward during heating and outward during cooling.
Heating operation
Adjust louvers downward.
Cooling operation
Adjust louvers outward.
Figure 2. Ceiling Mount Cassettes
MCFA or MCFB Ceiling- or Floor-Mounted Units
Use the wired or wireless remote control to set the position
of the discharge air louvers. The louvers may be set to
automatically swing. In this setting, horizontal louvers will
swing outward to downward and vertical louvers can be
manually adjusted from left to right.
You may also set the louvers so that they are stationary in
a single position. It is always recommended to direct the
horizontal discharge air louvers downward during heating
and outward during cooling.
Heating operation
Set horizontal louvers downward.
Cooling operation
Set horizontal louvers outward.
Horizontal Auto-Swing Operation
Sets louvers to pivot up and down automatically.
Vertical louvers can be manually
adjusted left to right.
Figure 3. Ceiling or Floor Mounted Units
MWMA, MWMB or 3WMB Wall-Mounted Units
Use the wired controller or the wireless remote control to
set the position of the discharge air louvers. The louvers
may be set to automatically swing between the outward
and downward positions, OR you may set the louvers so
that they are stationary in a single position. It is always
recommended to direct the horizontal discharge air louvers
downward during heating and outward during cooling.
Heating operation
Set horizontal louvers downward.
Coolingoperation
Set horizontal louvers outward.
Auto-swing operation
Sets louvers to pivot up and down automatically.
Figure 4. Wall Mounted Units
Maintenance
WARNING
ELECTRICAL SHOCK, FIRE, OR EXPLOSION
HAZARD.
Before performing any maintenance, power to unit must
be off at the unit disconnect switch.
IMPORTANT
Use a clean, dry cloth to wipe the wireless remote con-
trol. Never use a damp or wet cloth to clean the wireless
remote control.
Use a clean, dry cloth to wipe the indoor unit. If
necessary, dampened cloth may be used.
Do not use a chemically treated dust cloth on either the
indoor unit or wireless remote control.
Do not use benzene, paint thinner, polishing powder
or similar products to clean the indoor unit or control.
These substances may cause the plastic surface to
crack or become damaged.
Return Air Filters
Blocked or dirty return air lters affect system oper ation
and efciency. Air lters should be checked monthly in
order to ensure proper air ow to the in door unit. It may be
necessary to check the lter more frequently if the unit is
installed in an area with a large amount of dust.
The lter may be removed and cleaned, or it should be
replaced with a lter of like kind and size if it is impossible
to clean the lter. See “Figure 1. Parts Arrangement” on
page 2 to locate the lter in your indoor unit.

4
Filters are accessed through the return air grille as shown
in the illustration which follows.
Typical Filter Removal
Pivot hinged grille downward
Lift filter up and out to remove
it from the unit.
The filter may be cleaned using either a
vacuum cleaner or with clean water.
Filter Cleaning
Filter should be held
with the air entering side
face up when using a
vacuum cleaner.
The filter should be held with
the air entering side face down
when using clean water to wash
the filter.
Filter should be set aside to air
dry after cleaning. Do not
place filter in direct sunlight
or use any type ofheat to dry
the filter.
NOTE -If filter is extremely
dirty, it may be necessary to
tergent for cleaning. Filter must
be thoroughly rinsed and dried.
Spigot or
water hose
Filter
Vacuum
cleaner
Filter
M22A, M33A or M33B Ceiling-Mounted Cassettes
Simultaneously press two
latch relese buttons (M33A or M33B)
or slide grille release latches toward
the middle as shown (M22A)
Figure 5. Typical Filter Removal and Cleaning
Preparing Unit for Prolonged Idle Periods
The unit must be prepared before lengthy periods of
inactivity:
• Set the controller so the indoor unit operates in the fan
only mode for 8 to 12 hours.
• Thoroughly clean and replace return air lters.
• Use a clean, dry cloth to wipe cabinets.
• Turn the unit OFF at the wired controller or wireless re-
mote control; then, disconnect power to the unit.
• Remove batteries from the wireless remote control.
Returning the Unit to Operation after Prolonged
Idle Periods
If the unit has been inactive for an extended period of time,
it must be prepared for operation:
• Properly clean and replace return air lters.
• Use a clean, dry cloth to wipe unit front panels.
• Insert batteries into the wireless remote control.
• If power was disconnected, reconnect power to the
unit for at least 12 hours before returning the unit to
operation.

5
Troubleshooting
IMPORTANT
If any of the following conditions exist, immediately
turn the system (indoor and outdoor units) off at the
unit disconnect switch and call a licensed professional
HVAC technician (or equivalent) for repairs:
The system does not receive a signal from the wireless
remote control or wired controller.
The wireless remote control or wired controller indicate
a system malfunction.
Water is leaking into the room from the indoor unit.
The circuit breaker trips or the fuse blows frequently.
Water or some other liquid has been spilled on or
splashed into the indoor unit.
NORMAL OPERATION
If none of the above conditions exist, check the following
items before calling for repairs. This can save you both
time and money. The following are signs of normal system
operation.
System does not operate on command
The indoor fan does not start immediately after the ON/
OFF button on the wireless remote control is pressed.
• On an initial call for cooling, the operation/run light is lit
to signal normal operation. There will be a delay after
a cooling demand is introduced before unit operation
begins. This delay protects the unit compressor and is
normal.
• When a heating demand is initiated, the operation light
is lit to signal normal operation. The PRE-DEF indica-
tor may be lit as well. The indoor unit fan will not oper-
ate until the indoor coil reaches a pre-set temperature.
This prevents the delivery of cold air into the space
and is normal.
Indoor fan is on; compressor is off
In certain normal operating modes, the indoor fan is on
when the compressor is not operating.
• The system turns the compressor off and leaves the
indoor fan on when the indoor coil falls to a preset tem-
perature. This is normal operation and will prevent the
indoor coil from freezing.
• When the indoor fan is set for continuous operation,
the fan continues to run when the temperature setting
is reached and the compressor is de-energized.
White mist comes out of the indoor unit
• During cooling operation, if the indoor relative hu-
midity is very high and the indoor unit discharge air
louvers are very dirty, the indoor coil may freeze and
a white mist (frozen vapor) may appear to come from
the indoor unit. In this case, though the unit is not
in need of repair, it does need to be cleaned by a
licensed professional HVAC technician (or equiv-
alent).
• During heating operation when the operation
mode switches from defrost to heating, moisture
generated by the defrost process becomes steam and
may be seen as it is blown out of the indoor unit.
Sounds can be heard near the indoor unit
During certain parts of the heating or cooling process,
low swishing or groaning sounds may be heard near the
unit as the system pressures equalize. This is a normal
occurrence.
The table below lists possible causes and solutions to
some of the most common problems. Please review this
information before calling for service.

6
Table 1. Troubleshooting
Symptom Possible Cause Possible Solution
Unit does not start.
• Power failure
• Power to unit is OFF or disconnected
• Circuit breaker may be tripped or fuse may be
blown
• Wireless remote control batteries may have
lost their charge or unit controller may have
malfunctioned
• Wait for power to be restored
• Turn on or reconnect power to the unit
• Reset circuit breaker or replace fuse
• Replace AAA size batteries in wireless remote
control. Check controller for proper function
Indoor fan is operating; however, air is
not cool.
• Temperature not properly set at control
• Compressor may be kept off by delay
• Check temperature setting at control
• Wait for delay to expire
Unit cycles on and off frequently.
• Refrigerant charge is incorrect
• Air in refrigerant circuit
• Compressor malfunction
• Improper voltage
• System refrigerant circuit is blocked
• Check for refrigerant leaks and properly charge
system
• Evacuate and properly charge system
• Check compressor and replace, if necessary
• Check with utility company to provide proper
voltage
• Clear blockage
Unit not cooling properly.
• Indoor and/or outdoor coil are dirty
• Air lter is dirty
• Air ow around indoor and/or outdoor unit is
obstructed
• Doors and/or windows are open
• Direct sunlight is affecting indoor temperature
• Heat source inside is placing a large burden on
the system
• Suction pressure is low due to possible refrig-
erant leak
• Clean indoor and/or outdoor coil
• Clean or replace air lter
• Remove obstructions
• Close doors and windows
• Use curtains or blinds to block direct sunlight.
• Reduce burden of heat source
• Check for refrigerant leaks and properly charge
system
Unit not heating properly.
• Doors and/or windows are open
• Suction pressure is low due to possible refrig-
erant leak
• Close doors and windows
• Check for refrigerant leaks and properly charge
system
Fan speed cannot be changed.
Check the mode listed on the unit display. Fan
speed cannot be changed in the AUTO or DRY
mode
Fan speed cannot be changed in AUTO or DRY
mode. Change mode to COOL, FAN ONLY or HEAT.
Wireless remote control signal is not
being transmitted, even when ON/OFF
button is pressed.
Batteries may have lost their charge Replace AAA size batteries (2)
The TEMP adjustment indicator is not
available.
Check the mode listed on the unit display.
Temperature cannot be adjusted in the FAN ONLY
mode
Change the mode to COOL, HEAT or DRY
Operation indicator disappears from
the display after a period of time. Check to see if display reads TIMER OFF Timed operation is terminated at the end of the TIMER period
TIMER ON disappears from the display
after a period of time. Check to see if display reads TIMER OFF Timed operation is terminated when time period has expired.
No tones being sounded by indoor unit,
even when ON/OFF button is pressed.
• Infra-red receiver must be able to see signal
from wireless remote control
• Batteries may have lost their charge
• Aim wireless remote control infra-red transmitter
directly at receiver
• Replace AAA size batteries (2)

7
Error Codes
Indoor units are equipped with either a small panel
with four LEDs that ash to indicate system errors or a
digital display that provides an error code. Refer to the
appropriate table below to view the error codes. If the
unit has a digital display, the error code will replace the
temperature setting displayed on the front cover of the
indoor unit. If more than one error has occurred, the codes
will alternate so that all codes are shown. Make note of the
code (E1, EE, etc.), then reset the display by pressing the
ON/OFF button on the wireless remote controller. Press
the ON/OFF button a second time to reapply power to
system. If code is still displayed, disconnect and restore
power at the unit disconnect switch or circuit breaker. If
the problem was temporary, the code will not reappear.
If the error code reappears after power has been broken
and restored at the disconnect switch or circuit breaker,
call a licensed professional HVAC service technician.
Table 2. MWMA, MWMB and 3WMB
Troubleshooting Codes
Code Description
E0 Indoor unit EEPROM error
E1 Communication error between indoor unit and outdoor unit
E3 Indoor fan speed error
E4 Indoor return air temperature sensor error
E5 Indoor coil temperature sensor error
EC Low refrigerant
EE High water level alarm
F0 Outdoor current overload sensed
F1 Outdoor ambient temperature sensor error
F2 Outdoor coil temperature sensor error
F3 Compressor discharge temperature sensor error
F4 Outdoor unit EEPROM error
F5 Outdoor unit fan speed error
P0 Inverter module IPM error
P1 High or low voltage protection
P3 Outdoor unit low temperature lockout
P4 Compressor drive error
-- Mode conict
P6 Compressor high-pressure or low-pressure switch open
Table 3. MCFA, MCFB, MMDA, MMDB, M22A M33A
and M33B Troubleshooting Codes
Display Description
E0 Indoor unit EEPROM error
E1 Communication error between indoor and outdoor units
(E2 for outdoor code)
E3 Indoor fan speed error
E4 Indoor return air temperature sensor error
E5 Indoor coil temperature sensor error
EC Low refrigerant
EE High water level alarm (for ducted units only)
F0 Outdoor current overload sensed Note: (outdoor unit
display --) two dashes
F1 Outdoor ambient temperature sensor error (T4
malfunction) outdoor unit display E4
F2 Outdoor coil temperature sensor error (T3) Malfunction
outdoor unit display E4
F3 Compressor discharge temperature sensor error (T5)
Malfunction outdoor unit display E4
F4 Outdoor unit EEPROM error - outdoor display E0
F5 Outdoor unit fan speed error - outdoor Error display E8
P0 Inverter module IPM error - outdoor display P6
P1 High or low voltage protection - outdoor display E5
P3 Outdoor unit low temperature lockout - outdoor unit
display LP
P4 Compressor drive error
P6 Mode conict
P7 Compressor high- or low-pressure switch open - outdoor
unit display P2

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