Mitsubishi Electric PCA-A24KA4 User manual

SERVICE MANUAL
SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
SPLIT-TYPE, AIR CONDITIONERS
No. OCH484
INDOOR UNIT
CONTENTS
1. REFERENCE MANUAL................................... 2
2. SAFETY PRECAUTION................................... 3
3. PART NAMES AND FUNCTIONS....................4
4. SPECIFICATIONS............................................ 7
5. NOISE CRITERION CURVES..........................9
6. OUTLINES AND DIMENSIONS...................... 10
7. WIRING DIAGRAM......................................... 12
8. REFRIGERANT SYSTEM DIAGRAM............13
9. TROUBLESHOOTING................................... 14
10. SPECIAL FUNCTION.....................................28
11. DISASSEMBLY PROCEDURE.......................31
ON/OFF
TEMP.
COOL
DRY
AUTO
FAN
HEAT
Indoor unit
[Model names] [Service Ref.]
PCA-A24KA4 PCA-A24KA4
PCA-A30KA4 PCA-A30KA4
PCA-A36KA4 PCA-A36KA4
PCA-A42KA4 PCA-A42KA4
November 2010
NOTE:
• This manual describes only
service data of the indoor
units.
• RoHS compliant products
have <G> mark on the
spec name plate.
PARTS CATALOG (OCB484)
Model name
indication
33223
WIRED REMOTE
CONTROLLER
(Option) IR WIRELESS REMOTE
CONTROLLER (Option)

2
OUTDOOR UNIT’S SERVICE MANUAL
REFERENCE MANUAL
1
Model name Service Ref. Service Manual No.
PUZ-A18/24/30/36/42NHA4 PUZ-A18/24/30/36/42NHA4
OCH481
OCB481
PUZ-A18/24/30/36/42NHA4-BS PUZ-A18/24/30/36/42NHA4-BS
PUY-A18/24/30/36/42NHA4 PUY-A18/24/30/36/42NHA4
PUY-A18/24/30/36/42NHA4-BS PUY-A18/24/30/36/42NHA4-BS
Radio frequency interface Wired remote controller IR wireless remote controller
RF thermostat
Remote controller (Optional parts)
COOL
DRY
AUTO
FAN
HEAT
ON/OFF
TEMP.

3
SAFETY PRECAUTION
2
Cautions for units utilising refrigerant R410A
2-2. CAUTIONS RELATED TO NEW REFRIGERANT
Use new refrigerant pipes.
Store the piping to be used indoors during
installation, and keep both ends of the piping
sealed until just before brazing. (Leave elbow
joints, etc. in their packaging.)
Charge refrigerant from liquid phase of gas
cylinder.
If the refrigerant is charged from gas phase, composition
change may occur in refrigerant and the efficiency will be
lowered.
Do not use refrigerant other than R410A.
If other refrigerant (R22 etc.) is used, chlorine in refrige-
rant can cause deterioration of refrigerant oil etc.
Use a vacuum pump with a reverse flow check
valve.
Vacuum pump oil may flow back into refrigerant cycle and
that can cause deterioration of refrigerant oil etc.
Use the following tools specifically designed for
use with R410A refrigerant.
The following tools are necessary to use R410A refrigerant.
Handle tools with care.
If dirt, dust or moisture enters into refrigerant cycle, that can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refrigera-
nt will change and the efficiency will be lowered.
Flare tool
Electronic refrigerant
charging scale
Vacuum pump adaptor
Size adjustment gauge
Gauge manifold
Torque wrench
Gas leak detector
Charge hose
Tools for R410A
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil etc.
If dirt, dust or moisture enters into refrigerant cycle, that can
cause deterioration of refrigerant oil or malfunction of com-
pressor.
If large amount of mineral oil enters, that can cause deterio-
ration of refrigerant oil etc.
The refrigerant oil applied to flare and flange
connections must be ester oil, ether oil or
alkylbenzene oil in a small amount.
Make sure that the inside and outside of refrige-
rant piping is clean and it has no contaminants
such as sulfur, oxides, dirt, shaving particles, etc,
which are hazards to refrigerant cycle.
In addition, use pipes with specified thickness.
Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.
2-1. ALWAYS OBSERVE FOR SAFETY
Before obtaining access to terminal, all supply
circuits must be disconnected.
[1] Cautions for service
(1) Perform service after recovering the refrigerant left in unit completely.
(2) Do not release refrigerant in the air.
(3) After completing service, charge the cycle with specified amount of refrigerant.
(4) When performing service, install a filter drier simultaneously.
Be sure to use a filter drier for new refrigerant.

4
[3] Service tools
Use the below service tools as exclusive tools for R407C refrigerant.
Gravimeter
Unit
Indoor Unit
PART NAMES AND FUNCTIONS
3
Air outlet
Louver
Vane
Air intake
Filter
(Inside of Air intake)
[2] Additional refrigerant charge
When charging directly from cylinder
· Check that cylinder for R410A on the market is syphon type.
· Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.)
No. Tool name Specifications
1Gauge manifold · Only for R410A
· Use the existing fitting specifications. (UNF1/2)
· Use high-tension side pressure of 5.3MPa·G or over.
2Charge hose · Only for R410A
· Use pressure performance of 5.09MPa·G or over.
3Electronic scale —
4Gas leak detector · Use the detector for R134a, R407C or R410A.
5Adaptor for reverse flow check · Attach on vacuum pump.
6Refrigerant charge base —
7Refrigerant cylinder · Only for R410A · Top of cylinder (Pink)
· Cylinder with syphon
8Refrigerant recovery equipment —

5
°F°C
°F°C
ERROR CODE
AFTER
TIMER
TIME SUN MON TUE WED THU FRI SAT
ON
OFF
Hr
AFTER
FILTER
FUNCTION
ONLY1Hr.
WEEKLY
SIMPLE
AUTO OFF
PAR-21MAA
ON/OFF
FILTER
CHECK
OPERATION
CLEAR
TEST
TEMP.
MENU
BACK DAY
MONITOR/SET
CLOCK
ON/OFF
●
●
Display Section
For purposes of this explanation,
all parts of the display are shown
as lit. During actual operation, only
the relevant items will be lit.
Identifies the current operation
Shows the operating mode, etc.
*Multilanguage display is available.
“Centrally Controlled” indicator
Indicates that operation from the
remote controller has been prohib-
ited by a master controller.
“Timer is Off” indicator
Indicates that the timer is off.
Temperature Setting
Shows the target temperature.
Day-of-Week
Shows the current day of the week.
Time/Timer Display
Shows the current time, unless the simple or Auto Off
timer is set.
If the simple or Auto Off timer is set, the time to be
switched off is shown.
“Sensor” indication
Displayed when the remote controller
sensor is used.
“Locked” indicator
Indicates that remote controller but-
tons have been locked.
“Clean The Filter” indicator
To be displays on when it is time to
clean the filter.
Timer indicators
The indicator comes on if the corre-
sponding timer is set.
Up/Down Air Direction indica-
tor
The indicator shows the direc-
tion of the outcoming airflow.
“One Hour Only” indicator
Room Temperature display
Shows the room temperature. The room
temperature display range is 46-102°F.
The display blinks if the temperature
is less than 46°F or 102°F or more.
Louver display
Indicates the action of the swing louver.
Does not appear if the louver is not
running.
(Power On indicator)
Indicates that the power is on.
Fan Speed indicator
Shows the selected fan speed.
Ventilation indicator
Appears when the unit is running in
Ventilation mode.
Operation Section
Temperature setting buttons
Down
Up
Timer Menu button
(Monitor/Set button)
Mode button (Return button)
Set Time buttons
Back
Ahead
Timer On/Off button
(Set Day button)
Opening the
cover
ON/OFF button
Fan Speed button
Filter button
(<Enter> button)
Test Run button
Check button (Clear button)
Airflow Up/Down button
Louver button
( Operation button)
To return operation
number
Ventilation button
( Operation button)
To go to next operation
number
Note:
“PLEASE WAIT” message
This message is displayed for approximately 3 minutes when power is supplied to the indoor unit or when the unit is recovering from a power failure.
“NOT AVAILABLE” message
This message is displayed if an invalid button is pressed (to operate a function that the indoor unit does not have).
If a single remote controller is used to operate multiple indoor units simultaneously that are different types, this message will not be displayed as
far as any of the indoor units is equipped with the function.
Built-in temperature sensor
Displays if the airflow is set to
Low or downward during COOL
or DRY mode. (Operation varies
according to model.)
The indicator goes off in one hour,
at which time the airflow direction
also changes.
Wired remote controller (Option)