Mitsubishi Electric PL42FK21 User manual

OC194-1
CONTENTS
1.TECHNICAL CHANGE ··················································································OC194- 2
2. FEATURES ····································································································OC194- 3
3. PART NAME AND FUNCTIONS····································································OC194- 4
4. SPECIFICATIONS··························································································OC194- 6
5. DATA ··············································································································OC194- 8
6. OUTLINES AND DIMENSIONS ····································································OC194-17
7. REFRIGERANT SYSTEM DIAGRAM····························································OC194-19
8.WIRING DIAGRAM ························································································OC194-20
9. OPERATION FLOW-CHART··········································································OC194-22
10. MICROPROCESSOR CONTROL ··································································OC194-25
11.TROUBLESHOOTING····················································································OC194-36
12. 4-WAY AIR FLOW SYSTEM ········································································OC194-43
13. SYSTEM CONTROL ······················································································OC194-50
14. DISASSEMBLY PROCEDURE ······································································OC194-55
15. PARTS LIST ··································································································OC194-57
16. OPTIONAL PARTS ························································································OC194-63
PL12FK1
PL18FK21
PL24FK21
PL30FK21
PL36FK31
PL42FK21

OC194-2
1TECHNICAL CHANGE
Change points
Optional parts Program timer
FK2
Switch for temperature unit 
Switch for louvers 
— 
OFF 
Control change of the normal and twin 
Change of the unit No.1 and No.2 
— 
— 
PAC–SK65PT
Canceled 
Canceled 
Addition of "Mode selector" 
ON 
Addition of "Not yet used" 
Addition of "LOSSNAY interlocked or not" 
Addition of "Mode selector" 
Addition of "CN2L" 
PAC–SC32PTA
FK21
SW17 

SW18 
SW1 
SW5


SW6
No.9 
No.0 

No.10 
No.3 
No.4

Dip switch 


Dip switch
Appearances
Remote 
controller
Indoor controller
4-3/4o4-3/4o5/85-1/8o4-3/4o3/4


Connector for LOSSNAY interlocked
Differences with OC001 which is a basic service manual.

OC194-3
FEATURES
2
1. SPACE-SAVING CENTRALLY LOCATED CEILING RECESSED INSTALLATION
2. 4-WAY AIR FLOW SYSTEM
This series allows you to select from 2, 3, and 4 way air flow directions according to your requirement. As a result, you get
superb flexibility in choosing a configuration that gives you maximum cooling efficiency in a neat and unobstructive installa-
tion.
3. STABLE COOLING EVEN AT OUTDOOR TEMPERATURES AS LOW AS 0--F MAKES
YEARROUND AIR-CONDITIONING POSSIBLE.WIND BAFFLE REQUIRED.
The microprocessor automatically adjusts fan speed in accordance with outdoor temperature to maintain the coolant at an
even condensing temperature.The result is smooth, efficient cooling even when temperatures outdoors drop as low as 0-F.
This makes the unit ideal for a wide range of specialized cooling needs, such as rooms with many office machines or com-
puters and areas subject to strong sunlight.
4. ADVANCED MICROPROCESSOR CONTROL
(1) Easy to use Microprocessor (remote controller)
1) Ultra-Thin Remote Controller
The streamlined, wide controller is designed to blend with any kind of interior and the adoption of a sophisticated micro-
processor allows you to carry out a wide range of operations easily.
2) Attractive Liquid Crystal Display (LCD)
Units operation mode, set temperature, room temperature, timer setting, fan speed, and air flow direction are displayed
on the remote controller with the easily understood visual Liquid Crystal Display (LCD).
3) Convenient 24-Hour ON-OFF Timer
The timer allows Mr.SLIM to be switched on or off automatically at the time is shown on the LCD.
4) Self-Diagnostic Feature Indicates Faults Instantly
In the rare case when a problem occurs, the unit stops operating and the set temperature indicator changes to the self-
diagnostic indicator, indicating the location of the fault.
If the check switch is pressed twice, the unit stops operating and the check mode is initiated. The cause of the most
recent problem stored in the memory is displayed on the LCD. This is extremely useful for maintenance purposes.
5) Useful Memory Feature for Storing Instructions
The previous set value is memorized so that constant temperature control can be obtained. This is convenient when,
for example, a power failure occurs.
(2) Non-polar Two-Wire Remote Controller Cables
The non-polar, two-wire type remote controller cable is slim, installation is simple and trouble-free. Remote controller wire
can be extended up to 550 yards.
Models Cooling capacity SEER
PL12FK112,300 Btu/h 10.4
PL18FK2118,400 Btu/h 10.2
PL24FK2123,600 Btu/h 10.0
PL30FK2131,000 Btu/h 10.4
PL36FK3136,100 Btu/h 10.0
PL42FK2142,500 Btu/h 10.0
Indoor Unit
Remote controller
FILTER
CHECK MODE
TEST RUN
TIMER OFF TIMER 
CHECK SETTEMP.
CLOCK AUTO AUTO 
START STOP
SWING
FAN 
SPEED AUTO

RETURN
FAN

OC194-4
3PART NAMES AND FUNCTIONS
Remote controller operation buttons
TIMER OFF TIMER 
CHECK SETTEMP.
DRY COOL 
FAN
CLOCK AUTO AUTO 
START STOP
MODE TIMER ON/OFF CLOCK/TIMER FAN SPEED AIR DISCHARGE FILTER
CHECK
TEST RUN
AIR SWEEP
SETTEMP. TIMER SET
F
FAN 
SPEED
SWING
REMOTE CONTROLLER 
PAR-JC240KUS
AUTO 
RETURN
FILTER button
This resets the filter service indica-
tion display.
TIMER ON/OFF button
This switches between continuous
operation and the timer operation.
SET TEMPERATURE
button
This sets the room temperature.
The temperature setting can be per-
formed in 2-F units.
Setting range :
Cooling 65-F to 87-F
CLOCK/TIMER button
This sets or switches the current
time,start time and stop time.
FAN SPEED button
This sets the fan speed.
AIR DISCHARGE
button
This adjusts the vertical angle of the
ventilation.
ON/OFF button
This switches between the opera-
tion and stop modes each time it is
press. The lamp on this button
lights during operation.
OPERATION MODE
button
Press this button to switch the cool-
ing, electronic dry (Dehumidify),fan
modes.
Remote controller
Once the controls are set, the same operation mode can be repeated by simply pressing the
ON / OFF button.
CHECK-TEST RUN button
Only press this button to perform an
inspection check or test operation.
Do not use it for normal operation.
AIR SWEEP button
This switches the horizontal fan motion
(Swing louver) ON and OFF.
(This button does not operate in this
models.)

OC194-5
TIMER OFF TIMER 
CHECK SETTEMP.
DRY COOL 
FAN
CLOCK AUTO AUTO 
START STOP
MODE TIMER ON/OFF CLOCK/TIMER FAN SPEED AIR DISCHARGE FILTER
CHECK
TEST RUN
AIR SWEEP
SETTEMP. TIMER SET
F
FAN 
SPEED
SWING
REMOTE CONTROLLER 
PAR-JC240KUS
AUTO 
RETURN
Operation lamp
This lamp lights during operation,
goes off when the unit stops and
flashes when a malfunction occurs.
CENTRALLY
CONTROLLED display
This indicates when the unit is con-
trolled by optional features such as
central control type remote controller.
TIMER display
This indicates when the continuous
operation and time operation modes
are set.
It also display the time for the timer
operation at the same time as when
it is set.
OPERATION MODE display
This indicates the operation mode.
CHECK display
This indicates when a malfunction
has occurred in the unit which should
be checked.
display
This lamp lights when electricity is
supplied to the unit.
display
This displays the selected setting
temperature.
F
CLOCK display
The current time , start time and stop
time can be displayed in ten second
intervals by pressing the time switch
button.The start time or stop time is
always displayed during the timer
operation.
display
The temperature of the return air is
displayed during operation.The dis-
play range is 47°F to 97°F. The dis-
play flashes 47°F when the actual
temperature is less than 47°F and
flashes 97°F when the actual tem-
perature is greater than 97°F.
F
In this display example on the bottom left, a condi-
tion where all display lamps light is shown for
explanation purposes although this differs from
actual operation.
display
This display lights in the check mode
or when a test operation is per-
formed.
CHECK MODE
TEST RUN
display
This lamp lights when the filter needs
to be cleaned.
FAN SPEED display
The selected fan speed is displayed.
Caution
●Only the display lights when the unit is stopped and power supplied to the unit.
●When power is turned ON for the first time the (CENTRAL CTRL) display appears to go off momentarily but this is not a malfunction.
●When the central control remote control unit, which is sold separately, is used the ON-OFF button,OPERATION MODE button and SET
TEMP. button do not operate.
●“NOT AVAILABLE” is displayed when the AIR SWEEP button are pressed.
(AIR SWEEP function is not provided for PL series.)
FILTER
Remote controller display
AIR DISCHARGE display
This displays the air direction.

OC194-6
4SPECIFICATIONS




Capacity 
Power Consumption 
EER 
SEER 
INDOOR UNIT MODELS 
External finish 
Power supply 
Max.fuse size (time delay) 
Min.ampacity 
Fan motor 

Airflow Hi-Lo 
Moisture removal 
Sound level Hi-Lo 
Cond. drain pipe O.D. 

Dimensions 

Weight 
 External finish 

 Dimensions 

 Weight 
OUTDOOR UNIT MODELS 
External finish 
Sound level 
Power supply 
Max. fuse size (time delay) 
Min. ampacity 
Fan motor 

Compressor 

Crankcase heater 
Refrigerant control 

Dimensions 

Weight 
REMOTE CONTROLLER 
Control voltage (by bulit-in.transformer) 
REFRIGERANT PIPING 
Pipe size 

Connection method 

Between the indoor 
& outdoor units
*1 

*1 
*1 






Dry 
Wet 



W 
D 
H 


W 
D 
H 








Model (type) 




W 
D 
H 




Liquid 
Gas 
Indoors 
Outdoors 
Height difference 
Piping length
Btu/h 
kW 




V,phase,Hz 
A 
A 
F.L.A. 
CFM 
CFM 
Pints/h 
dB

in. 
in. 
in. 
in. 


in. 
in. 
in. 



dB(A) 
V, phase, Hz 
A 
A 
F.L.A. 

R.L.A. 
L.R.A. 
A(W) 

in. 
in. 
in. 
lb 



in. 
in. 


ft 
ft
Model

















PL18FK21
18,400 
1.88 
9.8 
10.2 
PL18FK21

Galvanized sheets with gray heat insulation 
115 , 1 , 60 
15 
2.0 
0.85 
680-460 
650-440 
5.3 
45-38 
1-1/4 
32-1/4 
32-1/4 
10-1/8 
64 
Munsell 0.70Y 8.59/0.97 
36-5/8 
36-5/8 
2-3/8 
22 
PU18EK1

Munsell 5Y 7/1 
53 
208-230, 1, 60 
20 
16 
0.75 
RH247NAB 
12 
37 
0.11/0.12 (23/28) 
Capillary tube 
34-1/4 
11-5/8 
33-1/2 
154 
With indoor unit 
indoor unit - remote controller : DC12V, Indoor unit - outdoor unit : DC12V 
Not supplied (optional parts) 
3/8 
5/8 
Flared 
Flared 
130 
130
PL24FK21
23,600 
2.48 
9.5 
10.0 
PL24FK21



15 
2.0 
1.1 
750-550 
660-480 
6.8 
47-39 
1-1/4 



64 





PU24EK1


55 

20 
16 
0.65+0.65 
NH33NBD 
11.5 
54 
0.16/0.17 (33/39) 



49-9/16 
207 



3/8 
5/8 


164 
164
Item
NOTES : *1.Rating conditions —indoor : 80°FDB,67°FWB outdoor :95°FDB,75°FWB. 
Operating range
Indoor intake air temperature
95°FDB,71°FWB 
67°FDB,57°FWB 

Outdoor intake air temperature
115°FDB 
0°FDB* 

Cooling

Maximum 
Minimum 

*In case of the wind baffle is installed.

(In case of the wind baffle is not installed, the minimum temperature will be 23°FDB.) 

PL12FK1
112,300 
1.23 
10.0 
10.4 
PL12FK1



15 
2.0 
0.75 
570-540 
420-400 
3.8 
43-35 
1-1/4 



60 





PU12EK 

50 

15 
11 
0.65 
RH167NAB 
8.9 
29 
0.11/0.12 (23/28) 



25-5/8 
105 



3/8 
5/8 


130 
130
INDOOR

GRILLE
MODELS : PL12FK1, PL18/24FK21

OC194-7




Capacity 
Power Consumption 
EER 
SEER 
INDOOR UNIT MODELS 
External finish 
Power supply 
Max.fuse size (time delay) 
Min.ampacity 
Fan motor 

Airflow Hi-Lo 
Moisture removal 
Sound level Hi-Lo 
Cond. drain pipe O.D. 

Dimensions 

Weight 
 External finish 

 Dimensions 

 Weight 
OUTDOOR UNIT MODELS 
External finish 
Sound level 
Power supply 
Max. fuse size (time delay) 
Min. ampacity 
Fan motor 

Compressor 

Crankcase heater 
Refrigerant control 

Dimensions 

Weight 
REMOTE CONTROLLER 
Control voltage (by bulit-in.transformer) 
REFRIGERANT PIPING 
Pipe size 

Connection method 

Between the indoor 
& outdoor units
*1 

*1 
*1 






Dry 
Wet 



W 
D 
H 


W 
D 
H 








Model (type) 




W 
D 
H 




Liquid 
Gas 
Indoors 
Outdoors 
Height difference 
Piping length
Btu/h 
kW 




V,phase,Hz 
A 
A 
F.L.A. 
CFM 
CFM 
Pints/h 
dB

in. 
in. 
in. 
in. 


in. 
in. 
in. 



dB(A) 
V, phase, Hz 
A 
A 
F.L.A. 

R.L.A. 
L.R.A. 
A(W) 

in. 
in. 
in. 
lb 



in. 
in. 


ft 
ft
Model

















PL36FK31
36,100 
3.76 
9.6 
10.0 
PL36FK31

Galvanized sheets with gray heat insulation 
115 , 1 , 60 
15 
2.0 
1.0+1.0 
1,170-850 
1,090-790 
10.9 
49-41 
1-1/4 
52-3/4 
32-1/4 
10-1/8 
99 
Munsell 0.70Y 8.59/0.97 
57-1/8 
36-5/8 
2-3/8 
35 
PU36EK1

Munsell 5Y 7/1 
55 
208-230, 1, 60 
30 
22 
0.75+0.75 
NH47NAD 
17.5 
87 
0.16/0.17 (33/39) 
Capillary tube 
38-3/16 
13-9/16 
49-9/19 
154 
With indoor unit 
indoor unit - remote controller : DC12V, Indoor unit - outdoor unit : DC12V 
Not supplied (optional parts) 
1/2 
3/4 
Flared 
Flared 
164 
164
PL42FK21
42,500 
4.40 
9.7 
10.0 
PL42FK21



15 
3.0 
1.2+1.2 
1,270-920 
1,200-870 
12.6 
49-42 
1-1/4 



101 





PU42EK2 

56 

40 
27 
0.8+0.8 
NH569NXA 
20 
105 
0.16/0.17 (33/39) 

38-3/16 
13-9/16 

260 



1/2 
3/4 


164 
164
Item
NOTES : *1.Rating conditions —indoor : 80°FDB,67°FWB outdoor :95°FDB,75°FWB. 
Operating range
Indoor intake air temperature
95°FDB,71°FWB 
67°FDB,57°FWB 

Outdoor intake air temperature
115°FDB 
0°FDB* 

Cooling

Maximum 
Minimum 

*In case of the wind baffle is installed.

(In case of the wind baffle is not installed, the minimum temperature will be 23°FDB.) 

PL30FK21
31,000 
3.10 
10.0 
10.4 
PL30FK21



15 
2.0 
1.0+1.0 
1,170-850 
1,090-790 
9.6 
49-41 
1-1/4 



99 





PU30EK1


55 

30 
20 
0.65-0.65 
NH41NAD 
14.0 
73 
0.16/0.17 (33/39) 

34-1/4 
11-5/8 

208 



1/2 
3/4 


164 
164
INDOOR

GRILLE
MODELS : PL30FK21, PL36FK31, PL42FK21

OC194-8
5DATA
MODELS : PL12FK1, PL18/24/30FK21, PL36FK31, PL42FK21
1. PERFORMANCE DATA
1) COOLING CAPACITY
Models
Indoor air Outdoor intake air DB temperature(°F)
PL12FK1


71 
67 
63 
71 
67 
63 
71 
67 
63 
71 
67 
63 
71 
67 
63 
71 
67 
63
TC 
14.3 
13.2 
12.1 
21.2 
19.8 
18.5 
27.4 
25.6 
23.8 
35..8 
33.2 
30.9 
41.7 
38.9 
36.4 
49.6 
46.1 
42.8
SHC 
7.1 
8.4 
9.3 
14.6 
16.0 
17.2 
17.8 
19.5 
20.5 
19.4 
22.6 
25.1 
27.1 
29.6 
32.0 
32.3 
35.0 
37.2
TPC 
1.06 
1.03 
0.99 
1.64 
1.60 
1.56 
2.15 
2.10 
2.05 
2.65 
2.59 
2.53 
3.22 
3.15 
3.08 
3.95 
3.88 
3.80
TC 
13.8 
12.8 
11.8 
20.6 
19.1 
17.9 
26.5 
24.7 
22.9 
34.5 
31.9 
29.8 
40.3 
37.5 
35.1 
47.8 
44.3 
41.1
SHC 
6.9 
8.2 
9.1 
13.6 
15.1 
16.1 
16.7 
18.0 
19.0 
19.1 
22.1 
24.6 
25.4 
28.1 
30.2 
30.0 
32.8 
34.9
TPC 
1.16 
1.12 
1.08 
1.77 
1.73 
1.70 
2.36 
2.30 
2.24 
2.88 
2.81 
2.75 
3.52 
3.44 
3.36 
4.25 
4.10 
4.00
TC 
13.2 
12.3 
11.4 
19.6 
18.4 
17.1 
25.3 
23.6 
22.1 
33.5 
31.0 
29.0 
38.6 
36.1 
33.5 
45.8 
42.5 
39.3
SHC 
6.8 
8.0 
9.0 
12.5 
14.0 
15.0 
15.2 
16.8 
18.1 
18.8 
21.6 
23.9 
23.5 
26.4 
28.1 
28.0 
30.6 
32.6
TPC 
1.27 
1.23 
1.18 
1.93 
1.88 
1.83 
2.57 
2.48 
2.43 
3.17 
3.10 
3.02 
3.85 
3.76 
3.67 
4.60 
4.40 
4.28
TC 
12.6 
11.8 
11.1 
18.7 
17.5 
16.3 
24.0 
22.6 
21.0 
31.4 
28.8 
26.9 
36.8 
34.5 
31.9 
43.5 
40.2 
37.1
SHC 
6.6 
7.8 
8.8 
11.6 
12.8 
13.9 
13.8 
15.4 
16.6 
18.5 
20.9 
23.1 
22.1 
24.5 
26.2 
25.7 
28.2 
29.7
TPC 
1.38 
1.34 
1.29 
2.10 
2.03 
1.98 
2.77 
2.69 
2.62 
3.44 
3.35 
3.28 
4.22 
4.10 
4.00 
4.85 
4.65 
4.45
TC 
11.9 
11.2 
10.4 
17.9 
16.5 
15.3 
22.8 
21.4 
20.0 
29.6 
27.4 
25.6 
34.9 
32.5 
30.2 
41.2 
37.7 
34.8
SHC 
6.4 
7.6 
8.4 
10.6 
11.7 
12.7 
12.5 
13.9 
15.2 
18.0 
20.4 
22.5 
20.2 
22.4 
24.2 
23.1 
25.3 
27.1
TPC 
1.50 
1.46 
1.40 
2.23 
2.17 
2.12 
3.00 
2.90 
2.81 
3.76 
3.63 
3.55 
4.56 
4.42 
4.30 
5.20 
4.95 
4.75
IWB 
(°F) 

75 85 95 105 115
420 
0.27
Airflow 
(CFM) 
B.F
PL18FK21650

0.17
PL24FK21660

0.13
PL36FK311090

0.15
PL42FK211200

0.14
PL30FK211090

0.15
Notes 1. B.F. :Bypass Factor, IWB : Intake air wet-bulb temperature 
TC :Total Capacity (x103 Btu/h), SHC : Sensible Heat Capacity (x103 Btu/h)

TPC :Total Power Consumption (kW) 
2. SHC is based on 80°F of indoor intake air DB temperature.
MODEL Refrigerant piping length (one way)
1.0 
1.0 
1.0 
1.0 
1.0
25ft (std)
0.992 
0.981 
0.981 
0.981 
0.975
40ft
0.983 
0.968 
0.968 
0.968 
0.955
55ft
0.978 
0.952 
0.952 
0.952 
0.935
70ft
0.966 
0.940 
0.940 
0.940 
0.918
85ft
0.959 
0.925 
0.925 
0.925 
0.900
100ft
0.950 
0.913 
0.913 
0.913 
0.884
115ft
0.945 
0.900 
0.900 
0.900 
0.869
130ft

0.886 
0.886 
0.886 
0.855
150ft

0.874 
0.874 
0.874 
0.840
164ft
PL12FK1

PL18FK21 

PL24FK21 

PL30FK21 

PL36FK31
PL42FK21
2) COOLING CAPACITY CORRECTIONS

OC194-9
2. PERFORMANCE CURVE
NOTES : A point on the curve shows the reference point.
PL12FK1COOLING CAPACITY PL18FK21COOLING CAPACITY
Total power consumption (kW) Total capacity (x103Btu/h)
Outdoor intake air DB temperature ( F)
24
21
12
18
15
2.5
2.0
1.5
1.0
63
67
71
63
67
71
SHF=0.76
0 32 35 45 55 65(67) 75 85 95 105 115
Indoor intake air WB temperature ( F)
Indoor intake air WB temperature ( F)
3.0
Total power consumption (kW) Total capacity (x103Btu/h)
Outdoor intake air DB temperature ( F)
18
18
6
1.4
1.2
1.0
0.8
63
67
71
63
67
71
SHF=0.77
032354555 65(67) 75 85 95 105 115
Indoor intake air WB temperature ( F)
Indoor intake air WB temperature ( F)
1.6

OC194-10
NOTES : A point on the curve shows the reference point.
PL24FK21COOLING CAPACITY PL30FK21COOLING CAPACITY
Total power consumption (kW) Total capacity (x103Btu/h)
Outdoor intake air DB temperature ( F)
36
30
42
24
4.0
3.5
3.0
2.5
63
67
71
63
67
71
SHF=0.76
23 32 35 45 55 65(67) 75 85 95 105 115
Indoor intake air WB temperature ( F)
Indoor intake air WB temperature ( F)
Total power consumption (kW) Total capacity (x103Btu/h)
Outdoor intake air DB temperature ( F)
30
24
36
18
3.0
2.5
2.0
1.5
63
67
71
63
67
71
SHF=0.71
23 32 35 45 55 65(67) 75 85 95 105 115
Indoor intake air WB temperature ( F)
Indoor intake air WB temperature ( F)
3.5
PL36FK31COOLING CAPACITY PL42FK21COOLING CAPACITY
Total power consumption (kW) Total capacity (x103Btu/h)
Outdoor intake air DB temperature ( F)
48
42
54
36
2.0
1.5 63
67
71
63
67
71
SHF=0.72
23 32 35 45 55 65(67) 75 85 95 105 115
Indoor intake air WB temperature ( F)
Indoor intake air WB temperature ( F)
Total power consumption (kW) Total capacity (x103Btu/h)
Outdoor intake air DB temperature ( F)
42
36
48
30
4.0
3.5
3.0
2.5
63
67
71
63
67
71
SHF=0.73
23 32 35 45 55 65(67) 75 85 95 105 115
Indoor intake air WB temperature ( F)
Indoor intake air WB temperature ( F)
4.5