Lennox MCFA User manual

1
MINI-SPLIT SYSTEMS SERVICE MANUAL
Indoor and Outdoor Unit Information
100029
5/2022
Table of Contents
Indoor Unit Information...................................3
1. M22A and M33C Cassette Non-Ducted Indoor Units ...............3
1.1. ModelNumberIdentication........................................................3
1.2. M22AIndoorUnitSpecications..................................................3
1.3. M33CIndoorUnitSpecications .................................................4
1.4. M22AIndoorUnitDimensions.....................................................5
1.5. M33CIndoorUnitDimensions.....................................................6
1.6. M22AandM33CIndoorUnitClearances....................................7
1.7. M22AandM33CIndoorUnitControlBoardSwitches
Location.......................................................................................8
1.8. M22AandM33CCondensateDrainTestProcedure...................9
2. MMDB Ducted Indoor Units......................................................10
2.1. MMDBModelNumberIdentication..........................................10
2.2. MMDBIndoorUnitSpecications..............................................11
2.3. IndoorUnitBlowerData ............................................................12
2.4. MMDBIndoorUnitDimensions .................................................18
2.5. MMDBIndoorUnitClearances..................................................19
2.6. CondensatePumpLift-MMDBandM22A/M33C.....................20
2.7. MMDBCondensateDrainTestProcedure.................................20
2.8. MMDBIndoorUnitGravityDrain ...............................................21
3. MWMC and 3WMC-036 Wall Mounted Indoor Units ............... 22
3.1. ModelNumberIdentication......................................................22
3.2. IndoorUnitSpecications(009-012Ton)Units ......................23
3.3. IndoorUnitSpecications(018-030Ton)Units .......................23
3.4. IndoorUnitSpecications(3WMC) ...........................................23
3.5. IndoorUnitDimensions(MWMCand3WMC)...........................24
3.6. IndoorUnitClearances(AllModelsandSizes) .........................25
3.7. MWMCand3WMC036S4UnitControlBoardSwitches
Location.....................................................................................25
3.8. DryModeOperation-MWMCand3WMC ................................26
3.9. TestRun-MWMCand3WMC ..................................................26
3.10. Double-CheckPipeConnections...............................................26
3.11. AmbientTemperatureisBelow63°F(17°C) .............................27
4. MCFA and MCFB Ceiling / Floor Indoor Units........................ 28
4.1. ModelNumberIdentication......................................................28
4.2. IndoorUnitSpecications(018-048Ton)Units .......................28
4.3. IndoorUnitDimensions .............................................................29
4.4. IndoorUnitClearances..............................................................30
4.5. MCFAandMCFBIndoorUnitControlBoardSwitches
Location.....................................................................................31
5. MFMA Floor Indoor Unit ...........................................................32
5.1. ModelNumberIdentication......................................................32
5.2. IndoorUnitSpecications(012Ton)Unit ..................................32
5.3. IndoorUnitDimensions .............................................................33
5.4. IndoorUnitClearances..............................................................33
6. Indoor and Outdoor Power and Communication
Wiring Requirements ...............................................................34
6.1. Overview....................................................................................34
6.2. WiringGuide..............................................................................35
MCFA and MCFB
M22A and M33C
MMDB
MWMC and 3WMC036
MPC, 3PC, and MLB
Single Zone
MLB and MPC
Multi-Zone
MFMA
Please refer to service manual 100030 for indoor and
outdoor unit error codes and component diagnostics.

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6.3. TerminalConnections ................................................................37
7. Wired and Wireless Remotes...................................................39
7.1. 22U49WirelessRemote............................................................39
7.2. 22U50WirelessRemote............................................................39
7.3. 22U52WirelessRemote............................................................39
7.4. M0STAT61Q-1andM0STAT61Q-2WiredRemotes..................39
8. Connection to Centralized Controller, ON/OFF and
Alarm Devices ..........................................................................40
8.1. SetIndoorUnitAddressforCentralizedControl
(UsedwithVRFOnly)................................................................40
8.2. CentralizedController................................................................41
8.3. ON/OFFDevices .......................................................................41
8.4. AlarmDevices ...........................................................................41
8.5. ConnectingCables ....................................................................41
Outdoor Unit Information..............................42
9. Single and Multiple Zone Outdoor Units.................................42
9.1. ModelNumberIdentication......................................................42
9.2. MPCSingle-ZoneSpecications(0.75-1.5Ton)......................43
9.3. MPCSingle-ZoneSpecications(2-4Ton)..............................44
9.4. 3PCSingle-ZoneSpecications................................................45
9.5. MLBSingle-ZoneSpecications(0.75-2Ton) .........................46
9.6. MLBSingle-ZoneSpecications(3-4Ton) ..............................47
9.7. MPCMulti-ZoneSpecications(1.5-2.5Ton) ..........................48
9.8. MPCMulti-ZoneSpecications(3-4Ton) ................................49
9.9. MLBMulti-ZoneSpecications(1.5-3Ton)..............................50
9.10. MLBMulti-ZoneSpecications(4Ton)......................................51
9.11. Single-ZoneOutdoorUnitDimensions ......................................52
9.12. Multi-ZoneOutdoorUnitDimensions ........................................53
9.13. OutdoorUnitClearances...........................................................54
10. Indoor / Outdoor Unit Combinations....................................... 56
10.1. MPCMulti-ZoneSystemCombinations.....................................56
10.2. MLBMulti-ZoneSystemCombinations .....................................62
11. Refrigeration Pipe Work ........................................................... 65
11.1. MPCand3PCSingle-ZoneRefrigerantCycleDiagram............65
11.2. MPCTwo-ZoneRefrigerantCycleDiagram ..............................65
11.3. MPCThree-ZoneRefrigerantCycleDiagram............................66
11.4. MPCFour-ZoneRefrigerantCycleDiagram .............................66
11.5. MPCFive-ZoneRefrigerantCycleDiagram ..............................67
11.6. MLBSix-ZoneRefrigerantCycleDiagram ................................67
11.7. Single-ZonePipingLimitations..................................................68
11.8. Multi-ZonePipingLimitations ....................................................68
12. Master Valves (3 to 5 Zone Outdoor Units).............................70
13. MPC Multi-Zone Outdoor Unit Connections and
Line Set Usage .......................................................................... 71
14. MLB Multi-Zone Outdoor Unit Connections and
Line Set Usage .......................................................................... 79
15. Power and Communication Wiring for Systems ................... 83
16. Outdoor Unit Condensate Piping ............................................ 84
17. MPC Condensate Pump Diagrams .......................................... 85
18. Installation Requirements ........................................................86
18.1. TorqueRequirements ................................................................86
18.2. PipeLengthandElevation.........................................................86
19. Electronic Function...................................................................89
19.1. Abbreviations.............................................................................89
19.2. ElectricControlWorkingEnvironment.......................................89
20. Start-Up...................................................................................... 89
20.1. AddingRefrigerant-Single-ZoneSystems ...............................89
20.2. AddingRefrigerant-Multi-ZoneSystems..................................90
21. Single-Zone Outdoor Unit LED Locations .............................. 91
22. Multi-Zone Outdoor Unit LEDs and SW1 Locations .............. 92
23. SpecicationsandOperations ................................................ 93
24. Pressure on Service Port ......................................................... 94
24.1. CoolingCharts...........................................................................94
24.2. HeatingChart ............................................................................94
24.3. CapacityRequestCalculations..................................................95
24.4. DefrostControl ..........................................................................98
24.5. DefrostTheory...........................................................................98
24.6. DefrostTermination....................................................................98
24.7. OutdoorFanControl..................................................................99
24.8. Four-WayValveControl...........................................................100
24.9. ElectronicExpansionValve(EXV)Control ..............................100

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Indoor Unit Information
1. M22A and M33C Cassette Non-Ducted Indoor Units
1.1. Model Number Identication
M 22 A 012 S 4 - 1 P
Unit Type
22 = 2x2 Cassette Non-Ducted Unit
33 = 3x3 Cassette Non-Ducted Unit
Series Type
M = Mini-Split
Voltage
P = 208/230V-1 phase-60hz
CASSETTE NON-DUCTED INDOOR UNITS
Cooling Efciency
S = Standard Efciency
Major Design Sequence
A = 1st Generation
B = 2nd Generation
C = 3rd Generation
Nominal Cooling Capacity
009 = .75 tons
012 = 1 tons
018 = 1.5 tons
024 = 2 tons
036 = 3 tons
048 = 4 tons
Refrigerant Type
4 = R-410A
Minor Design Sequence
1 = 1st Revision
2 = 2nd Revision
1.2. M22A Indoor Unit Specications
Model No. M22A009S4-*P M22A012S4-*P M22A018S4-*P
Nominal Tons 0.75 1 1.5
Power Supply - 60 hz - 1 phase 208/230V 208/230V 208/230V
Rated load amps 0.9 1.0 1.5
Output (W) 46 46 46
Room Temperature
Range (°F)
Cooling 62 - 90 62 - 90 62 - 90
Heating 32 - 86 32 - 86 32 - 86
Air Volume - cfm (High/Medium/Low) 375/300/255 380/310/260 560/485/415
Sound Data (dBA) - Low/Medium/High 33/37/41 36/39/43 36/39/44
Piping Connections - Liquid/Gas - o.d. - are - in. 1/4 / 3/8 1/4 / 1/2 1/4 / 1/2
Drain connection o.d. - in. 1 1 1
Net/Shipping weights - lbs. Body 32 / 38 36 / 41 36 / 42

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1.3. M33C Indoor Unit Specications
Model No. M33C024S4 M33C036S4 M33C048S4
Nominal Tons 2 3 4
Power Supply - 60 hz - 1 phase 208/230V 208/230V 208/230V
Rated load amps 1.0
Output (W) 45 125 125
Room Temperature
Range (°F)
Cooling 60 - 90 60 - 90 60 - 90
Heating 32 - 86 32 - 86 32 - 86
Air Volume - cfm (High/Medium/Low) 706 / 635 / 547 947 / 853 / 753 1171 / 1059 / 935
Sound Data (dBA) - Low/Medium/High 43 / 46 / 49 52.5 / 50 / 46.5 55 / 53 / 50
Piping Connections - Liquid/Gas - o.d. - are - in. 3/8 / 5/8 3/8 / 5/8 3/8 / 5/8
Drain connection o.d. - in. 1 1 1
Net/Shipping weights - lbs. Body 48 / 56 60 / 69 65 / 74

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1.4. M22A Indoor Unit Dimensions
SIDE VIEW
LEFT SIDE VIEW RIGHT SIDE VIEW
BOTTOM VIEW (Body)
DRAIN
CONNECTION
LIQUID
PIPE
GAS
PIPE
22-1/2 (572)
21-1/2 (546)
20-5/8
(524)
22-1/2
(572)
10-3/8
(264)
23-5/8 (600)
(Ceiling Opening)
INSTALLATION
HANGERS
LEVELING
ADJUSTMENT
NUT (4)
CEILING
DIFFUSER
PANEL
AIR
OUTLET
AIR
OUTLET
AIR
INLET
SIDE VIEW
BOTTOM VIEW (Panel)
25-1/2
(648)
25-1/2 (648)
Fresh Air Intake
(NOTE - Not Used)

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1.5. M33C Indoor Unit Dimensions
GAS
PIPE
LIQUID
PIPE
Fresh Air Intake
(NOTE - Not Used)
BOTTOM VIEW (Body)
SIDE VIEW
DIFFUSER
PANEL
AIR
OUTLET
AIR
OUTLET
AIR
INLET
BOTTOM VIEW (Panel)
37-3/8
(949)
37-3/8 (949)
5-1/2
(139)
4
(102)
DRAIN
CONNECTION
32-5/8
(829)
26-3/8
(670)
26-3/8
(670)
32-5/8 (829)
30-3/8 (772)
CONTROL BOX
HANGING BRACKETS (4)
CONDENSATE PUMP
CONNECTION
ELECTRICAL INLET
3-7/8
(98)
5-5/8
(143)
A
RIGHT SIDE VIEWLEFT SIDE VIEW
Size A
in. mm
024 8-1/8 206
036 9-5/8 244
048 11-1/4 286

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1.6. M22A and M33C Indoor Unit Clearances
23-5/8 (600)
(Ceiling Opening)
INSTALLATION
HANGERS
LEVELING
ADJUSTMENT
NUT (4)
CEILING
DIFFUSER
PANEL
AIR
OUTLET
AIR
OUTLET
AIR
INLET
36”
(914 mm)
36”
(914 mm)
36”
(914 mm)
36”
(914 mm)
Minimum Clearance from Structural Ceiling to Drop Ceiling:
M22A009, M22A012, M22A018 and M33C024 -- 10-1/4” (260 mm)
Minimum Clearance to Floor
(all models and sizes) - 98-1/2” (2500 mm)
M33C036 and M33C048 -- 13” (330 mm)

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1.7. M22A and M33C Indoor Unit Control Board Switches Location
SW2
Indoor Fan
Speed
Adjustment
(future version)
SW3
Auto Restart
Function
SW1
Pre-Heat Function
Adjustment
SW6
Heating Temperature
Compensation
Adjustment
S1+S2
CCM Address
(VRF only)
SW5
For Mode Conict
Setting
(24k and smaller
units only)
Figure 1. M22A Main Control Switches
SW2
Indoor Fan
Speed
Adjustment
SW3
Auto Restart
Function
SW5
For Mode Conict
Setting
(24k and smaller
units only)
SW1
Pre-Heat Function
Adjustment
SW6
Heating Temperature
Compensation
Adjustment
S1+S2
CCM Address
(VRF only)
Figure 2. M33C Main Control Switches

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1.8. M22A and M33C Condensate Drain Test
Procedure
CAUTION
Make sure that drain piping is properly routed and insu-
lated in order to prevent both leaks and condensation.
IMPORTANT
Drain should have a slope of at least ¼ inch per foot and
should be approved corrosion-resistant pipe. You must
conrm operation of every drain and pump in the system
as part of the commissioning procedure.
1. Use a eld-provided hose clamp to secure the drain line
stub on the side of the cassette base to a eld-supplied
1” (25 mm) drain line.
NOTE: Take care not to over-tighten the hose clamp as
this may damage the drain line stub.
2. See gure below for applications using the unit’s internal
condensate pump to provide lift into a drain. Ensure that
the main drain line is properly sloped (no less than 1/4
inch per foot (18 mm per m)).
3. Drain should be as short as possible and should not have
any droops or kinks that would restrict condensate ow
and shall be approved resistant pipe.
NOTE: There must be a 2-inch (51 mm) space between
the end of the condensate drain and the nal
termination point (ground, open drain, etc.) to
ensure that the line will drain freely.
After system installation is complete, the condensate
drain line must be checked for leaks and the condensate
pumps must be checked to ensure proper operation.
This check is part of the commissioning sequence. Pour
water into the evaporator drain pan to ensure proper
condensate drainage. See gure right. If a leak is found,
shut down power to the unit at once and do not restore
power to the unit until the problem has been resolved.
Drain Plug
Drain Pan
Cassette Base
Pour water
here for test
Cap
(Remove for test)
Figure 3. Condensate Drain Test
Cassette
Unit
7-7/8in.
2~3-15/16 in.
Drain
(slope of at least ¼ inch per foot)
Max. 28"
3 ft. (1 m)
SUPPORT
STRAPS
Figure 4. Indoor Unit Condensate Drain

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2. MMDB Ducted Indoor Units
NOTE: It is recommended that Medium Static Ducted Indoor Units not be installed in unconditioned spaces with
temperatures above 100°F.
2.1. MMDB Model Number Identication
M MD B 012 S 4 - 1 P
Unit Type
MD = Medium Static Ducted Unit
Series Type
M = Mini-Split
Voltage
P = 208/230V-1 phase-60hz
Cooling Efciency
S = Standard Efciency
Major Design Sequence
A = 1st Generation
B = 2nd Generation
Refrigerant Type
4 = R-410A
Minor Design Sequence
1 = 1st Revision
2 = 2nd Revision
Nominal Cooling Capacity
009 = .75 tons
012 = 1 tons
018 = 1.5 tons
024 = 2 tons
036 = 3 tons
048 = 4 tons

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2.2. MMDB Indoor Unit Specications
Model No. MMDB009S4 MMDB012S4 MMDB018S4
Nominal Tons 0.75 1 1.5
Power Supply - 60 hz - 1 phase 208/230V 208/230V 208/230V
Rated load amps 1.11 1.11 1.2
Output (W) 55 55 160
Room Temperature
Range (°F)
Cooling 62 - 90 62 - 90 62 - 90
Heating 32 - 86 32 - 86 32 - 86
Air Volume - cfm (High/Medium/Low) 355/285/175 355/285/175 530/450/370
External Static Pressure (in. w.g) 0 - 0.16 0 - 0.16 0 - 0.40
Sound Data (dBA) - Low/Medium/High 25/32/38 26/33.5/38 35/37/39
Piping Connections - Liquid/Gas - o.d. - are - in. 1/4 / 3/8 1/4 / 1/2 1/4 / 1/2
Drain connection o.d. - in. 1 1 1
Net/Shipping weights - lbs. 38 / 49 38 / 49 54 / 66
Model No. MMDB024S4 MMDB036S4 MMDB048S4
Nominal Tons 234
Power Supply - 60 hz - 1 phase 208/230V 208/230V 208/230V
Rated load amps 1.5 1.6 2
Output (W) 160 300 560
Room Temperature
Range (°F)
Cooling 62 - 90 62 - 90 62 - 90
Heating 32 - 86 32 - 86 32 - 86
Air Volume - cfm (High/Medium/Low) 775/695/435 1080/910/705 1230/1030/715
External Static Pressure (in. w.g) 0 - 0.64 0 - 0.64 0 - 0.64
Sound Data (dBA) - Low/Medium/High 36/41/44 39/42.5/45.5 46/48.5/50.5
Piping Connections - Liquid/Gas - o.d. - are - in. 3/8 / 5/8 3/8 / 5/8 3/8 / 5/8
Drain connection o.d. - in. 1 1 1
Net/Shipping weights - lbs. 87 / 103 106 / 122 120 / 142

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2.3. Indoor Unit Blower Data
2.3.1. MMDB009S4
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04 0.200.160.120.100.08
*SP1 Limit airflow rate setting on the controller.
High
Medium
Low
*SP1
Limit
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04
0.20
0.160.120.100.08
*SP2 Limit airflow rate setting on the controller.
High
Medium
Low
*SP2
Limit
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04 0.200.160.120.100.08
*SP3 Limit airflow rate setting on the controller.
High
Medium
Low
*SP3
Limit
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04
0.20
0.160.120.100.08
*SP4 Limit airflow rate setting on the controller.
High
Medium
Low
*SP4
Limit

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2.3.2. MMDB012S4
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04 0.200.160.120.100.08
*SP1 Limit airflow rate setting on the controller.
High
Medium
Low
*SP1
Limit
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04
0.20
0.160.120.100.08
*SP2 Limit airflow rate setting on the controller.
High
Medium
Low
*SP2
Limit
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04 0.200.160.120.100.08
*SP3 Limit airflow rate setting on the controller.
High
Medium
Low
*SP3
Limit
Air Volume - cfm
External Static Pressure - in. w.g.
470
530
590
645
705
410
355
295
235
175
120
60
0
0.04
0.20
0.160.120.100.08
*SP4 Limit airflow rate setting on the controller.
High
Medium
Low
*SP4
Limit

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2.3.3. MMDB018S4
Air Volume - cfm
External Static Pressure - in. w.g.
1060
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.640.48 0.560.10
*SP1
Limit
Low
Medium
High
Air Volume - cfm
External Static Pressure - in. w.g.
1060
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16
0.64
0.48 0.560.10
Medium
*SP2
Limit
Low
High
Air Volume - cfm
1060
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.640.48 0.560.10
*SP3
Limit
Low
Medium
High
Air Volume - cfm
1060
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16
0.64
0.48 0.560.10
*SP4
Limit
Low
Medium
High
*SP1 Limit airflow rate setting on the controller. *SP2 Limit airflow rate setting on the controller.
External Static Pressure - in. w.g. External Static Pressure - in. w.g.
*SP3 Limit airflow rate setting on the controller. *SP4 Limit airflow rate setting on the controller.

15
2.3.4. MMDB024S4
Medium
Air Volume - cfm
External Static Pressure - in. w.g.
1060
1294
1410
1530
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.640.48 0.560.10
*SP1
Limit
Low
Medium
High
Air Volume - cfm
1060
1294
1410
1530
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16
0.64
0.48 0.560.10
*SP2
Limit
Low
High
Air Volume - cfm
External Static Pressure - in. w.g.
1060
1294
1410
1530
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.640.48 0.560.10
*SP3
Limit
Low
Medium
High
Air Volume - cfm
External Static Pressure - in. w.g.
1060
1294
1410
1530
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16
0.64
0.48 0.560.10
*SP4
Limit
Low
Medium
High
*SP1 Limit airflow rate setting on the controller.
*SP3 Limit airflow rate setting on the controller.
External Static Pressure - in. w.g.
*SP2 Limit airflow rate setting on the controller.
*SP4 Limit airflow rate setting on the controller.

16
2.3.5. MMDB036S4
Air Volume - cfm
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56 0.640.10
*SP4
Limit
Low
Medium
High
*SP1 Limit airflow rate setting on the controller.
Air Volume - cfm
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56 0.640.10
*SP3 Limit airflow rate setting on the controller.
Air Volume - cfm
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56
0.64
0.10
*SP4 Limit airflow rate setting on the controller.
Low
Medium
High
*SP1
Limit
Low
Medium
High
*SP3
Limit
Medium
*SP2
Limit
Low
High
Air Volume - cfm
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56
0.64
0.10
*SP2 Limit airflow rate setting on the controller.

17
2.3.6. MMDB048S4
Medium
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56 0.64 0.72 0.800.10
*SP1
Limit
Low
Medium
High
*SP2
Limit
Low
High
*SP3
Limit
Low
Medium
High
*SP4
Limit
Low
Medium
High
*SP1 Limit airflow rate setting on the controller.
Air Volume - cfm
2470
2355
2235
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56 0.64 0.72
0.80
0.10
*SP2 Limit airflow rate setting on the controller.
Air Volume - cfm
2470
2355
2235
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56 0.64 0.72 0.800.10
*SP3 Limit airflow rate setting on the controller.
Air Volume - cfm
2470
2355
2235
External Static Pressure - in. w.g.
1060
1295
1410
1530
2120
2000
1885
1765
1650
1175
940
825
705
590
470
355
235
120
0
0.04 0.400.320.240.16 0.48 0.56 0.64 0.72
0.80
0.10
*SP4 Limit airflow rate setting on the controller.
Air Volume - cfm
2470
2355
2235

18
2.4. MMDB Indoor Unit Dimensions
ELECTRICAL
CONTROL
BOX
SUPPLY AIR
OPENING
1 FRESH AIR INTAKE
3-5/8 (92) Diameter (009 thru 018)
5 (127) Diameter (024 thru 048)
B
A
E
N
OPTIONAL BOTTOM
RETURN AIR OPENING
RETURN AIR
OPENING
AIR FILTER
SIDE VIEW FRONT VIEW
REAR VIEW
BOTTOM VIEW
TOP VIEW
AIR FILTER
ELECTRICAL
CONTROL
BOX
GAS
PIPE
LIQUID
PIPE
CONDENSATE
PUMP DRAIN
CONNECTION
CONVENTIONAL
DRAIN
CONNECTION
CONVENTIONAL DRAIN
CONNECTION
(Alternate Location)
MOUNTING
LUGS (4)
MOUNTING
LUGS (4)
D
C
J
H
G
P
M
K
L
F
1NOTE - Outdoor air enters unit AFTER air filter.
Size A B C D E F G H
in. mm in. mm in. mm in. mm in. mm in. mm in. mm in. mm
009 thru 012 27-5/8 702 7-7/8 200 19-7/8 505 17-3/4 451 30-3/4 781 5-3/8 137 21-1/8 537 1-1/8 29
018 34-5/8 879 8-1/4 210 26-1/2 673 23-5/8 600 37-7/8 962 5-1/2 140 27-3/4 705 2 51
024 43-1/4 1099 9-3/4 248 30-1/2 775 27-1/2 699 46-1/2 1181 5-1/2 140 36-1/2 927 2 51
036 53-1/2 1359 9-3/4 249 30-1/2 775 27-1/2 699 56-3/4 1441 5-1/2 140 46-3/4 1187 2 51
048 47-1/4 1200 11-7/8 302 34-3/8 873 31-1/2 800 50-1/2 1283 4-7/8 124 41-1/8 1045 2 51
Size J K L M N P
in. mm in. mm in. mm in. mm in. mm in. mm
009 thru 012 6 152 23-5/8 600 7-3/8 187 2 51 29-1/8 740 14-1/8 359
018 5-3/8 137 30-3/4 781 7-1/2 191 1-5/8 41 36-1/4 921 20 508
024 6-7/8 175 39-3/8 1000 9 229 1/4 6 44-7/8 1140 23-1/2 597
036 6-7/8 175 49-5/8 1260 9 229 1/4 6 55-1/8 1400 23-1/2 597
048 9 229 43-3/8 1102 11 279 1/4 6 48-7/8 1241 27-1/2 699
Figure 5. MMDB Indoor Ducted Unit Dimensions - Inches (mm)

19
2.5. MMDB Indoor Unit Clearances
20 (508) Minimum Service Clearance (rear)
24 (610) Minimum
Service Clearance (front)
Air
Flow
24 (610)
Minimum
Service
Clearance
TOP VIEW
MEDIUM
STATIC
DUCTED
UNIT
FRONT VIEW
1 (25) Minimum Clearance (top)
Ceiling
Wall
Wall
* 1 (25) Minimum Clearance (bottom)
CeilingSuspended
* NOTE - Bottom unit clearance can be 1 inch (25 mm),
but allow 12 inches for filter removal on end
return air applications
* See footnote

20
2.6. Condensate Pump Lift - MMDB and
M22A/M33C
MMDB, M22A and M33C factory pumps have a 27 inch
condensate pump lift.
2.7. MMDB Condensate Drain Test
Procedure
CAUTION
Make sure that drain piping is properly routed and insu-
lated in order to prevent both leaks and condensation.
IMPORTANT
Drain should have a slope of at least ¼ inch per foot and
should be approved corrosion-resistant pipe. You must
conrm operation of every drain and pump in the system
as part of the commissioning procedure.
1. Use a eld-provided hose clamp to secure the drain line
stub on the side of the unit chassis to a eld-supplied 1”
(25 mm) drain line. See gure below.
NOTE: Take care not to over-tighten the hose clamps this
may damage the drain line stub.
INSULATION
INDOOR
UNIT
CONDENSATE
LINE STUB
HOSE CLAMP
FLEXIBLE DRAIN
CONNECTOR PVC DRAIN
PIPE
Figure 6. Condensate Piping Connection
2. Make a water-tight connection between the eld-provided
condensate drain line and the exible condensate
connector. Use 1-1/2” OD / 1-1/4” ID PVC pipe for the
drain line.
3. See gure for applications including an indoor unit using
the internal drain pump.
4. In all cases, drain should be as short as possible and
should not have any droops or kinks that would restrict
condensate ow and shall be constructed using an
approved pipe. There must be a 2-inch (51 mm) space
between the end of the condensate drain and the nal
termination point (ground, open drain, etc.) to ensure that
the line will drain freely.
SUSPENSION RODS
DRAIN LINE
STRUCTURAL CEILING
8 in.
(203 mm)
Max. 28 in.
SUPPORT
STRAPS
3 ft. (1 m)
Figure 7. Condensate Drain with Pump
5. After system installation is complete, the condensate
drain line must be checked for leaks and the condensate
pumps must be checked to ensure proper operation. This
check is part of the start-up process which must be done
by the installing contractor. Turn the condensate drain pan
test cover latch counterclockwise to open the cover and
access the drain pan. See gure below. Funnel enough
water to engage the pump into the drain pan through a
exible tube.
6. Operate the system in the cooling mode. If the internal
pump is being used, ensure that the pump is operating
and the water in the pan is draining freely. If the internal
pump is not being used, pour the water into the drain pan
and conrm that it has owed freely out of the pan and
out of the drain termination. If a leak is found, shut down
power to the unit at once and do not restore power to the
unit until the problem has been resolved.
7. Return the test cover and turn the latch clockwise to re-
lock it.
DRAIN PAN
TEST COVER
FUNNEL WATER INTO
PAN THROUGH TUBE
FOR TEST
COVER LATCH
(Turn latch
counterclockwise
to unlock)
CL
OSE
D
O
PE
N
CLOS
E
D
O
PE
N
NOTE: If using the gravity drain on the MMD unit,
make sure you install the black plug into the clear
pump drain connection to prevent water from
discharging if the gravity drain becomes restricted.
Gravity drain with black plug installed.
Figure 8. Condensate Drain Test