Service
manual
Portable air conditioners
51AKA 006
51AKB 006G RTB 165G VTB 075C
51AKM 006G RTE 165G
51AKB 008G RTB 205C
Contents page
1. ASSEMBLY DRAWINGS ..........................................................................................3
2. PARTS DESCRIPTION..........................................................................................4/5
2.1 Control panel..................................................................................................6/7
2.2 Accessories supplied........................................................................................8
2.3 Dimensions and weight ....................................................................................8
3. TECHNICAL DATA .................................................................................................... 8
4. PERFORMANCE DIAGRAMS.............................................................................9/10
5. WIRING DIAGRAMS.......................................................................................... 11/13
6. REFRIGERANT CIRCUIT PRINCIPLE OF OPERATION..................................... 14
7. R-407c REFRIGERANT.......................................................................................... 14
7.1 General............................................................................................................ 14
7.2 Main differences between R-407c and R22 refrigerant ...........................15/16
8. MICROPROCESSOR CONTROL .......................................................................... 17
8.1 Special functions of the buttons..................................................................... 17
8.2 Logic connection diagram .............................................................................. 17
8.3 Flow charts .................................................................................................18/20
8.4 Resistance values of room temperature sensor ...........................................21
9. UNIT DISASSEMBLY.........................................................................................21/24
10. TROUBLESHOOTING .......................................................................................25/28
10.1 Component testing procedure........................................................................ 29
1 1. OPTIONAL ACCESSORIES..............................................................................30/31
2
1
ASSEMBLY DRAWINGS
mod. 51AKB 006G
51AKB 008G
RTB 165G
RTB 205C
mod. VTB 075C
mod. 51AKA 006
mod. 51AKM 006G
RTE 165G
3
2
PARTS DESCRIPTION
Exhaust air outlet
Flexible duct
Air outlet
Control panel
Air outlet
(for ventilation,
dehumidification
and heating only)
Supply cable with plug
4
Air inlet
2
PARTS DESCRIPTION
Air filters
Condensate collection tank
5
Condensate drain tube
2.1 Control panel
mod. 51AKB 006
RTB 165F
mod. 51AKB 06G
RTB 165G
mod. VTB 075F
VTB 075G
1. OFF position
2. Mode selector
3. TURBO cooling
4. SILENT cooling
5. Dehumidification
6. Low fan speed
7. High fan speed
8. Ventilation function indicator light
9. Cooling indicator light
10. Dehumidification indicator light
11. Full water tank alarm indicator light
12. Thermostat
1. ON - OFF push button
2. Cooling - fan only push button
3. Thermostat
4. ON and alarm indicator light
5. Dehumidification push button
6. High - low speed fan push button
6
2.1 Control panel
mod. 51AKM 006
51AKM 06G
RTE 165F
RTE 165G
mod. VTE 075F
VTE 075G
1. ON-OFF button
2. Mode selector
3. Temperature setting button
4. Fan speed setting button
5. Operation on timer
6. Operation off timer
7. Low fan speed LED
8. High fan speed LED
9. ON timer LED
10. OFF timer LED
11. Display of set temperature and
programmed operating times
12. Set temperature LED
13. Heating LED
14. Dehumidification LED
15. Cooling LED
16. Fan only LED
7
2.2 Accessories supplied
1. Air outlet vent
2. Flexible hose
3. Fastening strap with suction cup
2.3 Dimensions and weight
kg
27.5
3
Cooling capacity W
Heating capacity W
Power input W
– cooling
– heating
– dehumidification
Locked rotor amps A
Operating current A
– cooling
– heating
– dehumidification
Dehumidification rate l/h
– cooling
– dehumidification
Air flow
(fan speed) l/s - rpm
– high-speed cooling
– low-speed cooling
– high-speed heating
– low-speed heating
– high-speed dehumidification
– low-speed dehumidification
Recommended fuse size A
Supply voltage
TECHNICAL DATA
Model
(Btu/h)
(Btu/h)
51AKB 006 / 51AKB 06G
RTB 165F / RTB 165G
VTB 075F / VTB 075G
1830
6300
---
---
750
---
640
16
3.3
---
2.9
1.1
0.8
88.9 - 1320
72.2 - 1100
---
---
---
111.1 - 1100
16
51AKM 006 / 51AKM 06G
RTE 165F / RTE 165G
VTE 075F / VTE 075G
1830
6300
1000 + 1000
3410 + 3410
750
1000 + 1000
640
16
3.3
4,35 + 4,35
2.9
1.1
0.8
88.9 - 1320
72.2 - 1100
88.9 - 1320
72.2 - 1100
138.9 - 1320
111.1 - 1100
16
230V - 1 - 50Hz
8
4
PERFORMANCE DIAGRAMS
Cooling capacity, Watt
Cooling capacity, Watt
Indoor dry bulb temperature °C
(1) Relative humidity
The cooling capacity diagram is based on the room dry bulb temperature
for three different relative humidity values.
80% (1)
60% (1)
40% (1)
Cooling capacity, Btu/h
80% (1)
60% (1)
40% (1)
Cooling capacity, Btu/h
Indoor dry bulb temperature °C
Power input, Watt
80% (1)
60% (1)
40% (1)
Power input, Watt
Indoor dry bulb temperature °C
(1) Relative humidity
The power input diagram is based on the room dry bulb temperature
for three different relative humidity values.
9
4
PERFORMANCE DIAGRAMS
Suction temperature °C
80% (1)
60% (1)
40% (1)
Suction temperature °C
Discharge air temperature °C
Indoor dry bulb temperature °C
(1) Relative humidity
The air discharge temperature diagram is based on the room dry bulb temperature and relative humidity.
Due to the temperature differences of the air at the outlet, the thermometer must be placed exactly in
the position shown in the sketch.
Discharge air temperature °C
Indoor dry bulb temperature °C
80% (1)
60% (1)
40% (1)
Discharge air temperature measuring point
10
5
WIRING DIAGRAMS
mod. 51AKB 006 / 51AKB 06G
mod. RTB 165F / RTB 165G
“RS” CONTACT POSITIONS
POSITION
CONTACT
Legend
CPS Power supply cable
WS Full tank switch
CM Compressor
CC Compressor capacitor
IFM Indoor fan motor
IFC Indoor fan capacitor
TAF Antifreeze thermostat
CDP Condensate drain pump
TA Room thermostat
CWT Compressor overload protector
RS Rotary switch
X1 Terminal block
C1 Indoor fan connector
C2 Pump connector
C4 Top panel connector
C5 Compressor connector
11
Wire colours
O Orange
A Brown
B Blue
R Red
C Black
W White
G Grey
Y-G Yellow-Green
Note:
The connection sequence does not
represent the physical layout.
5
WIRING DIAGRAMS
mod. VTB 075F / VTB 075G
Legend
CC Compressor capacitor
CDP Condensate drain pump
CM Compressor
CPS Power supply cable
CWT Compressor overload protector
C1 Indoor fan connector
C2 Pump connector
C3 Compressor connector
C4 Heater connector
C6 Lamp board connector
IFC Indoor fan capacitor
IFM Indoor fan motor
LB Lamp board
TA Room thermostat
WS Full tank switch
X1 Terminal block
SW1 On-off switch
SW2 Fan speed change switch
SW3 Heat-cool switch
SW4 Dehumidifier switch
HTR Electric heater
ST Safety thermostat
F1 Thermal fuse
TAF Antifreeze thermostat
12
Wire colours
A Brown
B Blue
G Grey
R Red
W White
Y-G Yellow-Green
Bk Black /
Note:
The connection sequence does not
represent the physical layout.
Nero
5
WIRING DIAGRAMS
mod. 51AKM 006 / 51AKM 06G
mod. RTE 165F / RTE 165G
mod. VTE 075F / VTE 075G
Legend
CPS Power suppply cable
TAF Antifreeze thermostat
HTR Electric heater
CC Compressor capacitor
IFM Indoor fan motor
WS Full tank switch
CWT Compressor overload protector
HTP Heater thermal protector
IFC Indoor fan capacitor
CDP Condensate drain pump
X1 Terminal block
CM Compressor
NTC Air sensor
CB Control board
PB Power board
C1 Compressor connector
C2 Pump connector
C4 PB connector
C5 Indoor fan connector
C6 Heater connector
C7 CB connector
C8 CB connector
C9 CB connector
13
Wire colours
A Brown
B Blue
R Red
O Orange
C Black
W White
G Grey
V Violet
Y-G Yellow-Green
Note:
The connection sequence
does not represent the
physical layout.
6
REFRIGERANT CIRCUIT PRINCIPLE OF OPERATION
1. Compressor
2. Condenser
3. Fan
4. Filter
5. Capillary tube
6. Evaporator
7. Gas discharge
8. Liquid
9. Liquid/gas
10. Gas suction
7
R-407c REFRIGERANT
7.1 General
51AKB06G, 51AKM06G, RTB165G, RTE165G, VTB075G
and VTE075G units use the new refrigerant R-407c.
R-407c is a blend of three basic constituents: R32, R125,
R-134a with respectively weight composition 23%, 25%,
52%.
R-407c is an HFC refrigerant that does not destroy ozone
layer.
General behaviour of R-407c systems is very similar to
standard R22 one; system differences linked to R-407c
are below:
Since R-407c is a zeotropic blend, during phase change,
liquid composition is different from vapour one; for this
reason in case of leakage in zones with biphase, residual
refrigerant composition could be changed.
R-407c phase changes are not at constant temperature as
in R22 case, but with increasing temperature during
evaporation and with decreasing temperature during
condensation (Glide effect).
In case of refrigerant recharge, in order to assure correct
composition two following steps will have to be followed:
• Residual refrigerant in the system will have to be pulled
out and stored in a disposal cylinder (do not ventilate in
ambient).
• Refrigerant charge will have to be done only with
liquid phase in order to guarantee proper refrigerant
composition inside the system; this can be done or using
dedicated cylinders with two valves (one for liquid, the
other for vapour) or in case of one valve cylinder, put
cylinder in up side down position.
• In case of too much refrigerant charged, it is dangerous
to remove partially the charge; this could change
refrigerant composition inside the sistem; in such case it
is suggested to remove completely the refrigerant
charge, pull vacuum again and recharge the sistem with
proper amount of refrigerant.
Leak detection will have to be carryed-out only with HFC
sensitive leak detector.
Even if R-407c refrigerant is ozone friendly, do not ventilate
it in the ambient because its warming effect is not zero.
For all other technical details see standard rooles for R22.
14
7.2 Main differences between R-407c and R22 refrigerant
R-407c R22
Refrigerant charging procedure
Refrigerant composition
Refrigerant charging procedure
Refrigerant composition
Partial refrigerant charge:
NOT PERMITTED!
Complete refrigerant charge only.
Leak detector
Use HFC detector only.
Partial refrigerant charge:
YES!
Partial refrigerant charge allowed.
Leak detector
Use HCFC detector only.
15
7.2 Differences between R-407c and R22 units
R-407c R22
Temperature trend in evaporator
Temperature trend in condenser
Temperature trend in evaporator
Temperature trend in condenser
16
8
MICROPROCESSOR CONTROL
8.1 Special functions of the buttons
Pressing two buttons at the same time it is possible to activate
some functions which are NOT described in the Instruction
Manual.
Self-Test
If the
and “fan speed” buttons are pressed simultaneously
the sequence outlined in the table 1 will start.
Press any button to leave the Self-Test mode. At this point the
unit will automatically enter the maximum cooling mode.
Reset
If the Timer On and Timer Off buttons are pressed
simultaneously the unit will return to the same condition it was
in just after the first time the plug was connected to the socket:
cooling mode, hi-speed fan and 22 °C room temperature set
point.
Provided the pressure difference between discharge and
suction is acceptable (because the compressor worked for
few seconds), it is possible to restart the unit in this way even
if three minutes have not yet elapsed from the previous stop.
8.2 Logic connection diagram
Table 1
Test
Activated function
1
electric heater + LOW SPEED
fan (only for models with
Duration
7 seconds
electric heaters)
2
3
4
LOW SPEED
fan
HI SPEED
fan
compressor +
7 seconds
7 seconds
HI SPEED fan
(dehumidification)
5
compressor
7 seconds
+ HI SPEED fan
condensate drain pump
continuous
(maximum cooling WITHOUT
thermostat)
Tank
micro switch
Pump
Fan
Air
sensor
Low
speed
LED
TR1
Pump
TRIAC
TR3
High speed
TRIAC
TR4
Low speed
TRIAC
CONTROL PCB
High
speed
LED
Feed back
TRIAC
Control
circuit
TRIAC
Timer ON
LED
Fan speed
Timer OFF
LED
MICROPROCESSOR
button
Timer ON
button
RELAY CONTROL CIRCUIT
RELAY 3
compressor
Temperature
LED
Timer OFF
button
RELAY 2
heater 2
Heating
LED
Temperature
set button
RELAY 1
heater 1+2
Dehumidification
LED
DISPLAY
Operating
mode button
DC +12 V
Cooling
LED
ON / OFF
button
Fan only
LED
DC + 5V
DC
+12 / +5V
AC + 12V
TRANSFORMER
Compressor Heater 2 Heater 1+2
17
POWER PCB
NEUTRAL LIVE
POWER SUPPLY
8.3 Flow charts
POWER
PLUG
CONNECTED
PLUG
CONNECTED
VALID
FUNCTIONS
MEMORY
YES
UNIT WAS ON
WHEN PLUG
WAS REMOVED
YES
UNIT IS ACTIVATED
IN THE SAME MODE
AS BEFORE
THE PLUG
WAS REMOVED
STOP
NO
NO
APPEARS
ON THE DISPLAY
A POINT
NO YES
ON/OFF BUTTON
IS PRESSED
FOR 1 SECOND
MINIMUM
YES
SWITCH OFF
ON/OFF
ON/OFF BUTTON
IS PRESSED
UNIT IS OFF
STOP
DISPLAY IS
ACTIVATED
5 SECONDS
DELAY
SWITCH ON
COOLING MODE
FAN STARTS AT THE
SELECTED SPEED
THE SELECTED
TEMPERATURE APPEARS
ON THE DISPLAY
ROOM TEMP . >
SELECTED TEMP . +1°C
COMPRESSOR IS OFF
FOR MORE THAN
NO
THE UNIT IS FED
FOR MORE THAN
COMPRESSOR AND
CONDENSATE DRAINAGE
MOTOR ARE STARTED
START
YES
3 MINUTES
YES
3 MINUTES
YES
NO
ROOM TEMP . <
SELECTED TEMP . –1°C
YES
COMPRESSOR
IS STOPPED
OPERATING MODE IS
SWITCHED ON 5 SECONDS AFTER
THE RELEASE OF THE
“MODE SELECTION BUTTON”
NO
ROOM TEMP . >
SELECTED TEMP .
+1°C
NO
FAN SPEED
IS SELECTED
YES
ROOM TEMP . <
SELECTED TEMP .
–2°C
YES
BOTH HEATERS
ARE ACTIVA TED
AND FAN IS PUT
AT HIGH SPEED
HEATING MODE
START
HEATERS ARE
NO
DEACTIVA TED
AND FAN IS PUT
AT LOW SPEED
YES
NO ROOM TEMP . <
NO
SELECTED TEMP .
–1°C
YES
ONE HEATER
IS ACTIVA TED
AND FAN IS PUT
AT LOW SPEED
IN HEATING MODE THE FAN
SPEED LED SHOWS
THE SELECTED SPEED
AND NOT THE ACTUAL ONE
18
8.3 Flow charts
DEHUMIDIFICA TION
MODE
START
ROOM
TEMPERATURE
< 10°C
NO
“– –” APPEARS
ON DISPLAY
FAN
IS STARTED
AT LOW
SPEED
COMPRESSOR
IS STARTED
SELECTING DEHUMIDIFICATION MODE
FAN WORKS AT LOW SPEED.
FAN SPEED CAN BE CHANGED LATER.
YES
COMPRESSOR
AND FAN
ARE STOPPED
TIMER
ON *
START
UNIT IS DEACTIVATED
AND TIMER ON LED
IS SWITCHED ON (m)
“X” HOURS ELAPSED
FROM TIMER ON
SELECTION
YES
UNIT IS ACTIVATED
STOP
* SUPPOSING THAT TIMER ON
WAS SET TO ACTIVATE THE UNIT
AFTER “X” HOURS.
FAN SPEED LED AND
OPERATING MODE ACCORDING
TO SELECTION DONE.
NO
LOW
SPEED
FAN SPEED IS CHANGED
AFTER 1 SECOND DELAY.
NO YES
FAN ONLY MODE
START
“– –” APPEARS
ON DISPLAY
HI SPEED
WAS
SELECTED
HI
SPEED
TIMER
OFF *
START
LED IS SWITCHED
ON LOW LIGHT m
“X” HOURS ELAPSED
FROM THE TIMER OFF
SELECTION
YES
UNIT IS DEACTIVATED
STOP
NO
19
* SUPPOSING THAT TIMER OFF WAS SET
TO DEACTIVATE THE UNIT AFTER “X” HOURS.
TIMER OFF, FAN SPEED LED
AND OPERATING MODE ACCORDING
TO THE SELECTION DONE.
8.3 Flow charts
COMBINED
TIMER *
START
FAULTY SENSOR
DIAGNOSIS
START
YES NO
TIMER ON
TIMER OFF
(DEACTIVATION SCHEDULED
SEE
SEE
* SUPPOSING THAT TIMER ON WAS SET TO:
DEACTIVATE THE UNIT AFTER “X” HOURS
ACTIVATE THE UNIT AFTER “Y” HOURS.
X > Y
AFTER ACTIVA TION)
STOP
SEE
TIMER OFF
SEE
TIMER ON
FAULTY SENSOR
TIMER DEACTIVATED
(IF RUNNING)
NO
TEMP. <25°C OR
TEMP. >75°C
YES
FAUL TY
SENSOR TIMER
WORKING
YES
LED ‘°C’
AND DISPLAY
FLASH
FAULTY SENSOR
TIMER SCHEDULE
> 1 HOUR
YES
FAULTY SENSOR
TIMER IS DEACTIVATED
UNIT IS
DEACTIVATED
STOP
FAULTY SENSOR
TIMER ACTIVA TED
NO
TANK
ALARM
START
TANK IS FULL
OR NOT CORRECTLY
INSERTED
YES
COMPRESSOR,
CONDENSATE DRAIN
MOTOR,
FAN,
HEATERS,
LED
ARE DEACTIVATED
‘AL’
IS FLASHING
ON DISPLAY
NO
FAN
CONTROL
DIAGNOSIS
START
FAN CONTROL FAULTY
OR
FAN NOT CONNECTED
YES
UNIT IS DEACTIVATED
FAN SPEED LED FLASHES
TO LEAVE THE ALARM CONDITION IT IS NECESSARY
TO REMOVE THE PLUG FROM THE POWER SUPPLY SOCKET,
ELIMINATE THE CAUSE OF THE FAULT
AND RE-INSERT THE PLUG IN THE SOCKET.
NO
20
8.4 Resistance values of room temperature sensor
TEMPERATURE
°C
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
MINIMUM RESISTANCE VALUE
(ohm)
14792
14131
13505
12910
12346
11809
11300
10815
10355
9917
9500
9103
8726
8366
8024
7697
7386
7090
6807
6537
6279
NOMINAL RESISTANCE VALUE
(ohm)
15824
15092
14399
13743
13120
12530
11970
11439
10934
10455
10000
9568
8157
8766
8394
8041
7704
7384
7079
6788
6511
MAXIMUM RESISTANCE VALUE
(ohm)
16734
15949
15206
14502
13835
13203
12604
12036
11497
10985
10500
10039
9601
9185
8790
8414
8056
7716
7392
7084
6791
9
UNIT DISASSEMBLY
Remove the plug from socket.
It is not necessary to remove the exhaust air flexible duct from its housing (two holes).
21
9
UNIT DISASSEMBLY
Front panel removal
Unscrew the six screws placed on unit back and remove the front panel.
Control panel template removal
Remove the control panel template levering
on the two hooks placed in its lower part.
In this way all the electrical and electronic parts of
control panel can be reached and it is also possible
do all checks and parts substitutions of the same
panel.
Control panel removal
Release the control panel pushing the plastic tab
with a screwdriver and extract the panel sliding it
towards the right.
Control PCB removal
Important: Discharge the body static electricity touching
a metal part before touching the PCB.
Slightly pull apart the two plastic body sides which fasten
the PCB in order to release and remove it.
22
9
UNIT DISASSEMBLY
Electromechanical control removal
Remove the plug-in switch knob, release the plastic tab
and remove the switch end the board.
Rear panel removal
Remove the condensate tank in the rear of the unit.
Unscrew the four side clamping screws, lift the back panel about 10 mm and finally remove it.
At this point it is possible to make any check and/or service operation on the unit.
Power PCB replacement
Important: Discharge the body static electricity touching
a metal part before touching the PCB.
Disconnect polarized connector of power PCB.
Then disconnect the four cables complete with terminals.
Push with a sharp tool in the hole in order to release
the PCB from the clamp and to extract it.
23
9
UNIT DISASSEMBLY
Fan motor replacement
Disconnect the polarized electronic connector and TH sensor.
Using a screwdriver release the four plastic tabs that keep
the half scroll of the fan in place.
In this way it is possible to extract the motor from the
rubber vibration isolators which are supporting it.
If one or more plastic tabs of the half scroll of the fan are
broken, the half scroll can be secured by similar screws to
the ones used in the unit, during the re-assembly.
Electric heater removal
(models 51AKM 006, 51AKM 06G, RTE 165F,
RTE 165G, VTE 075F, VTE 075G)
Disconnect the polarized electric connector.
Remove the securing screw, release the plastic tab,
slide the electric heater compartment toward the right
and then remove the electric heater compartment and
the heater itself.
Coil removal
Remove the air flow flap and its holder.
Remove the pipe conduit plate releasing the six
plastic tabs which secure it to the unit.
Extract the refrigerant from the unit using a suitable
device and avoiding to exhaust it in the atmosphere.
Unsolder and disconnect coil piping and then
remove it.
24
TROUBLESHOOTING
10
Mod. 51AKM 006, 51AKM 06G, RTE 165F, RTE 165G, VTE 075F, VTE 075G
Autodiagnostic
In the event of malfunctions, a warning will be given automatically on the display.
SIGNAL
flashes on the display and LEDs off
–
– Display and
– Fan speed LED flashing
Attention
The operation outlined by * requires momentary connection between parts under voltage
and therefore they must be executed with caution.
In case of difficulties with the connection it is better to replace the power PCB.
If the trouble disappears the problem is solved. If not reutilize the old power PCB and replace
the control PCB.
LED flashing
– Water tank full or not correctly inserted
– Ambient air thermostat not working
(the unit will operate for 1 hour)
– Electronic Printed Circuit Board
defective or fan not connected
CAUSE
– Empty the water tank or check that it is
correctly inserted
– Replace the room temperature sensor
– Replace the control PCB or
connect the fan
Trouble Action Remedy
Unit does not work at all. Check the supply voltage.
Disconnect connector A on the power
PCB and verify that there are 12 VAC
between the pin A4 and the pin A2
(or between pin A4 and the quick
connector F2).
Call an electrician in case it is more than
15% less than the nominal voltage.
Replace the power PCB if there are not
12 VAC. If not replace the control PCB.
REMEDY
Compressor and fan do not work
in Cooling and in Dehumidification
modes.
Compressor does not work
and the fan is working in Cooling
and in Dehumidification modes.
Verify if Timer On was activated.
The message
and the LEDs are on (Dehumidification
mode only)
The message
and the LEDs are off.
Check the supply voltage.
Check the resistance of air sensor.
Check if there is voltage between quick
connector F1 and both the quick
connectors of relay RL3.
If voltage is found, check if compressor
thermal protection is closed.
If compressor thermal protector is okay,
check compressor winding resistance
(see Table 2 of page 57).
blinks on the display
flashes on display
Deactivate Timer On pushing the
corresponding button until the message
appears on the display.
Unit cannot run in the Dehumidification
mode when the temperature is less
than 10 °C.
Empty the condensate tank or place it
in the correct position.
Call an electrician in case it is more than
15% less than the nominal voltage.
Replace air sensor if necessary.
Replace compressor thermal protector
if necessary.
Replace compressor if necessary.
*
If no voltage is found disconnect
connector A on the power PCB, connect
contact A3 of the power PCB to quick
connector F2 and check if relay RL3 trips
or not.
25
If relay does not trip it is necessary to
replace the control PCB otherwise the
power PCB.
TROUBLESHOOTING
10
Trouble Action Remedy
Mod. 51AKM 006, 51AKM 06G, RTE 165F, RTE 165G, VTE 075F, VTE 075G
Unit does not work and both fan
speed LEDs are blinking.
Fan motor is continuously
cycled on-off by its built-in
overload protector.
Compressor motor is continuously
cycled on-off by its built-in overload
protector.
Check the start capacitor.
Connect the fan motor directly to the
supply.
Check the supply voltage.
Check if run capacitor is shorted
or grounded.
Check the maximum motor speed.
Ensure that the coils are clean and their
fins are not damaged.
Check supply voltage
Check if air temperature is lower than
maximum allowed one.
Check fan speed. (A low speed might
cause discharge pressure increase).
Replace start capacitor if necessary.
Replace the motor in case it does
not work; if motor works replace the
control PCB.
Call an electrician in case it is more
than ±10% of the nominal voltage.
Replace capacitor if necessary.
Replace motor in case speed is too low.
Clean or straighten the fins.
Call an electrician in case it is more than
±10 of the nominal voltage.
If fan speed is too low at maximum
speed it is necessary to replace the
motor
The cooling effect is not sufficient.
Ensure that the condenser coil is clean
and its fins are not damaged.
Check compressor and condenser.
Check if refrigeration circuit is partially
or totally clogged.
Air filter is clogged.
Ensure that the condenser and cooler
coils are clean and their fins are not
damaged.
Compressor motor is continuously
cycled on-off by its overload protector.
Refrigerant charge is not sufficient.
Check fan speed when motor is at
maximum speed and supplied right
voltage.
Clean or straighten the fins.
Replace it if it does not work.
Replace the clogged parts and recharge
the circuit.
Clean or replace the air filter.
Clean or straighten the fins.
See previous trouble.
Remove the charge, identify and repair
any possible leaks and recharge the
circuit.
If speed is too low, lubricate with oil the
bearing. If speed is still too low it is
necessary to replace the motor.
Check if refrigeration circuit is partially or
totally clogged.
Too much frost on cooler.
Compressor is unable to create the
necessary pressure differential.
26
Replace the clogged parts and recharge
the circuit.
See separate section “Too much frost
on cooler”.
Check compressor current and replace
compressor if necessary.
TROUBLESHOOTING
10
Trouble Action Remedy
Mod. 51AKM 006, 51AKM 06G, RTE 165F, RTE 165G, VTE 075F, VTE 075G
Too much frost on cooler.
Unit does not cool at all.
Unit is too noisy. Set the fan position in the scroll.
Air filter is clogged.
Check fan speed.
Outside air temperature is too low.
Compressor relay contacts are welded.
Cooler fins are bent and they partially
close the air passage.
Refrigerant charge is not sufficient.
Compressor does not work.
The charge is too low or has escaped.
Check if refrigeration circuit is partially or
totally clogged.
The fan hits the scroll.
The copper lines vibrate and touch parts
of the unit.
The noise is due to the compressor.
Clean air filter.
Replace motor if fan speed is too low.
Put the unit in Fan Only mode until
outside coil is defrosted.
Replace power PCB.
Straighten the fins.
Remove the charge, identify and repair
any possible leaks and recharge the circuit.
See section “Compressor does work
and the fan is working in Cooling and in
Dehumidification modes”.
Add refrigerant, identify and repair any
possible leaks and recharge the circuit.
Replace the clogged parts and recharge
the circuit.
Set the copper line position.
Replace the compressor.
The fan does not work in
Fan Only mode.
The heater and the fan do not work
in Heating mode
The heater does not work when fan is
operating at low speed and the low or
high speed was selected.
One of the heater stages does not
work when fan is operating at high
speed and the high speed was
selected.
Verify if Timer On was activated.
Verify if Timer On was activated. Deactivate Timer On pushing the
Remove and insert the plug into the
socket in order to reset PTC protection.
Select high fan speed and set the
thermostat at 27 °C in order to activate
both the stages of the heater.
Check air temperature sensor.
Check if there is voltage between quick
connectors F1 and F4.
* Disconnect connector A on the power
PCB, connect contact A5 of PCB to
quick connector F2 and check if the
relay RL2 trips if no voltage is found.
Check if there is voltage between
quick connectors F1 and F4.
* Disconnects connector A on the power
PCB, connect contact A5 of PCB to
quick connector F2 and check if relay
RL2 trips in case no voltage is present.
Deactivate Timer On pushing the
corresponding button until the message
appears on the display.
corresponding button until the message
appears on the display.
If heater restarts clean filters and fins.
Clean filters and fins and replace the
heater if fan works at high speed and
only one or none of the heater stages
operates.
Replace air temperature sensor if
necessary.
Replace the heater, clean filters and fins
if voltage is present.
Replace control PCB in case relay RL2
trips; if not replace power PCB.
Replace the heater, clean filters and fins
if voltage is present between quick
connectors F1 and F4.
Replace control PCB in case relay RL2
trips; if not replace power PCB.
Both heater stages do not work when
fan is operating at low speed and the
high speed was selected.
Check if there is voltage between quick
connectors F1 and F3.
* Disconnects connector A on the power
PCB, connect contact A3 of PCB to
quick connector F2 and check if relay
RL1 trips in case no voltage is present.
27
Replace the heater, clean filters and fins
if voltage is present.
Replace control PCB in case relay RL1
trips; if not replace power PCB.
TROUBLESHOOTING
10
Trouble Action Remedy
Mod. 51AKM 006, 51AKM 06G, RTE 165F, RTE 165G, VTE 075F, VTE 075G
The condensate tank is filled
in Cooling Mode.
The condensate tank is properly
positioned and empty, the message
blinks on display in any working
mode.
Both the display and the LEDs are
off, but the unit is properly working.
Place the exhaust air duct in vertical
position and pour a glass of water
on the condensing coil.
Connect the condensate drain pump
directly to the supply.
LEDs are on.
Check the tank microswitch in case the
LEDs are not on.
Check microswitch wiring.
10.1 Component testing procedure (all models)
A) Leaks
Torch leak detector use
To carry out a leak test of a refrigerant circuit it is
necessary to move the sensor pipe terminal of the leak
detector along all the joints and the parts containing
refrigerant.
Maximum sensitivity of the detector can be obtained by
keeping the flame high enough to get a red copper plate.
The flame is blue if there is no refrigerant in the air.
When the sensor pipe draws in air containing refrigerant the
colour of the flame changes according to the concentration
of the refrigerant in the air.
1. A small leak will cause the flame colour to switch from
blue to green.
2. A large leak will cause the flame colour to switch from
blue to violet.
Attention! Do not inhale the fumes of the leak detector
when the sensor pipe is drawing in air heavily polluted with
refrigerant.
B) Electric parts
Electric conductors
Remove the plug from the socket and check the continuity
of all the conductors and jumpers.
Available power supply
Low voltage is the most common problem.
Voltage must be read by an accurate and reliable voltmeter
when the unit is working in Cooling Mode. The meter sensors
must be inserted in the sensor in parallel with the unit.
Components tests
In case of a suspected electric fault first test the circuit to
identify the faulty part.
The tests must be carried on using a TESTER suitable for
troubleshooting.
Change-over switch
1. Remove the plug from the socket.
2. Insert the tester in the different positions of the changeover switch shown in the wiring diagram to check the
continuity between the contact and the corresponding
position of the change-over switch.
This test must be carried out only when all cables are
disconnected from the change-over switch.
Replace the control PCB in case
the motor works (the noise of the
drained water can be easily heard).
Replace the motor in case
it does not work.
Unit cannot work in Dehumidification
Mode if temperature is lower than 16 °C.
Replace microswitch if necessary.
Restore wiring if open, or replace the
wiring itself if necessary. Replace the
control PCB if the wiring is okay.
Replace the control PCB.
In case of a fault of any electric component, to identify the
problem and to solve it apply the procedures described on
the next pages. To carry out these tests it is necessary to
remove unit front panel.
Supply cable
Check the voltage at the terminals while the plug is
connected to the socket.
Room thermostat
(mod. 51AKB 006, 51AKB 06G, RTB 165F, RTB 165G,
VTB 075F, VTB 075G only)
1. Remove the plug from the socket.
2. Insert the tester according to the wiring diagram
indication and put the thermostat knob to the maximum
cooling position to check the continuity between
thermostat contacts.
This test must be carried on only when all cables are
disconnected from the thermostat.
28
10.1 Component testing procedure
Capacitor
body
Capacitor
T o capacitor
body
T o each
terminal
Capacitors
Remove the plug from the socket and remove the cables
from the capacitor. Discharge the capacitor, shortcircuiting
its terminal with the blade of a screwdriver.
Take an Ohmmeter and select the x 100 scale. Then
connect the sensors of the Ohmmeter to two terminals of
the capacitor.
a) If the capacitor is in order the needle will go
immediately
to zero and then will indicate high resistance.
b) If the capacitor is shorted the needle will go to zero and
stop in that position.
c) To check if a capacitor with metallic body is shorted it is
necessary to put a sensor of the Ohmmeter in contact
with a terminal of the capacitor and the capacitor body.
If capacitor is shorted the instrument will indicate
the electric continuity.
d) To check the capacitor polarity it is necessary to put the
Ohmmeter terminals on the capacitor terminals,
verifying
that the needle goes to zero and then indicates
the maximum resistance.
Then reverse the position of the Ohmmeter sensor on
the capacitor terminals: the needle will go to zero and
then come back to the normal position.
In this way the capacitor will be discharged and then
recharged by the Ohmmeter battery.
Compressor thermal overload protection
The test of the compressor thermal overload protection
(Klixon) must be carried on before the continuity test;
remove the plug and the connection cables from the
thermal overload protection. Be sure that the protection is
cool and closed. If necessary the Klixon must be removed
from the compressor body and cooled before the test.
Capacitor
Fig. 2Fig. 1
Compressor
Compressor
Before carrying out the test all cables must be
disconnected from the compressor, and its motor must be
checked to be sure that its windings are not shorted and/or
interrupted. Then:
1) Put a lead of the test circuit in contact with the
compressor body in an unpainted area in order to check
the insulation.
2) Put one of the leads on terminal “C” and the other one
on terminal “S” of the compressor in order to check the
continuity of the start winding.
3) Secure one of the leads on the compressor terminal “C”
and the other one on terminal “R” of the compressor in
order to check the continuity of the run windings.
Check that winding resistances correspond to the figures
given in the table 2 and that there is no ground leakage.
Air temperature sensor
(mod. 51AKM 006, 51AKM 06G, RTE 165F, RTE 165G,
VTE 075F, VTE 075G only)
Disconnect the sensor and using a tester in Ohmmeter
mode check that the sensor resistance corresponds to the
figure stated in the table on page 21.
Fan motor
Before the test it is necessary to rotate the fans by hand to
ensure that their bearings are not seized and their wheels
do not touch the housing.
Remove the plug and check the run capacitor to be sure
that it is properly working; then:
1) Connect the motor with the run capacitor directly in the
circuit. If the motor does not work it has to be replaced.
2) In case the motor works but the current drawn is too
high it is necessary to see if the motor is shorted
checking all connecting cables.
Table 2
Winding resistance at 25
°C
Compressor C - R 4.81 Ω
C - S 7.08 Ω
Fan White - Grey 125 Ω
White - Blue 146 Ω
29
11
OPTIONAL ACCESSORIES
Window installation
Wall installation
1200
300
30
11
Filter kit
OPTIONAL ACCESSORIES
Activated carbon filter Electrostatic filter Filter frames
31
L010119H31 - 0397
Carrier S.p.A. - Via R. Sanzio, 9 - 20058 Villasanta (MI) Italy - Tel. 039/3636.1
The manufacturer reserves the right to change any product specifications without notice.
Order No. 15173-74, March 1997. Supersedes Order No. (new). Printed in Italy
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