Bosch ACS 751 Setup guide

ACS 651/751
en Repair instructions
A/C service unit

1 689 975 223 2013-10-21| Robert Bosch GmbH
2 | ACS 751/651 |en
Contents English
1. Important information 4
2. Testing and resources 4
3. Description 5
3.1 ACS 651/751 5
3.1.1 Front view 5
3.1.2 Rear view 5
3.2 Components 6
3.2.1 Mounting place 6
3.2.2 Human Machine Interface (HMI) 6
3.2.3 Refrigerant cylinder 7
3.2.4 Pressure manifold 7
3.2.5 Vacuum pump 7
3.2.6 Compressor 7
3.2.7 Fan 7
3.2.9 I/O board 8
3.2.8 Human Machine Interface board
(main board) 8
4. Troubleshooting 9
4.1 By status messages 9
4.2 By symptoms 15
4.3 Entering the debug mode 16
4.4 Overview of actuators 16
5. Scales 16
5.1 Calibration of scales 16
5.1.1 Fresh Oil / used oil / UV dye scales 16
5.1.2 Calibration of the refrigerant tank
scale 17
5.2 Replacing scales 18
5.2.1 Replacing used oil/fresh oil/ UV dye
scale 18
5.2.2 Replacing scale assembly for
refrigerant cylinder 19
6. Panels 19
6.1 Opening the top panel 19
6.2 Opening the front panel 20
6.3 Opening the rear panel 20
6.4 Opening the right panel 20
6.5 Opening the left panel 20
6.6 Replacing the front wheels 21
6.7 Replacing the rear wheels 21
7. HMI module 21
7.1 Opening the HMI 21
7.2 Replacing the LCD 22
7.3 Replacing the printer 22
7.4 Replacing the keypad 23
7.5 Replacing the pressure gauges 23
8. Boards 24
8.1 Replacing the HMI board 24
8.2 Replacing the Switch Mode Power Supply
(SMPS) 24
8.3 Replacing the I/O board 24
9. Refrigerant cylinder 25
9.1 Replacing the refrigerant cylinder 25
9.2 Air purging 25
9.3 Replacing the air purge manifold on the
cylinder 26
9.4 Replacing the temperature sensor on the
cylinder 27
10. Pressure Manifold 28
10.1 Replacing the valve block of the pressure
manifold 28
10.2 Replacing the hoses between the
cylinder and the pressure manifold 28
10.3 Replacing the POE solenoid valve 29
10.4 Replacing the POE plug 30
11. Vacuum pump 30
11.1 Replacing the vacuum pump 30
11.2 Checking the vacuum pump function 31

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| ACS 751/651 | 3ACS 751/651 | 3| 3 en
12. Compressor and fan 31
12.1 Replacing the compressor 31
12.2 Checking the compressor function 32
12.3 Replacing the fan assembly 32
13. Replacing the wiring
harness 33
13.1 Replacing the wiring harness 1 33
13.2 Replacing the wiring harness 2 33
13.3 Replacing the wiring harness 3 33
13.4 Replacing the wiring harness 4 34
13.5 Replacing the wiring harness 5 34
13.6 Replacing the wiring harness 6 34
13.7 Replacing the connecting cable for the
temperature sensor 34
13.8 Replacing the USB host cable 34
13.9 Replacing the LED board cable 34
14. Replacing Hoses 35
14.1 Replacing the PA11 hose between the
compressor and the manifold 35
14.2 Replacing the PA11 hose for the HP/LP gauge 35
15. Replacing power supply 36
15.1 Replacing the cable socket 36
15.2 Replacing the fuse 36
14.3 Replacing the PA12 hose for the vacuum pump 36
14.4 Replacing the PA12 hose for the compressor 36
14.5 Replacing the silicon rubber hose for
Fresh-Oil, Used-Oil and UV-Dye 36
14.6 Replacing the hose between the oil separator
and the compressor 36
16. Test Points 37
17. Hydraulic circuit diagram 38
18. Electrical terminal diagram 39

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4 | ACS 751/651 | Important informationen
1. Important information
Installation and/or repairs may only be carried out by
trained and instructed Robert Bosch GmbH
customer service staff or organizations authorized by
Robert Bosch GmbH. Opening or modification of the
units by unauthorized persons will invalidate all
warranty entitlements.
Electrical systems and equipment may only be com-
missioned in proper condition (see Testing Technology
Information 0108_084 for details). This requirement
is met if, after modification or repair (initial test), it is
ensured that the requirements of the electrical engi-
neering regulations are adhered to. To verify this, tests
should be performed, the type and scope of which
should be based on the measures defined in the electri-
cal engineering regulations (e.g. in Germany BGV A3).
In Germany, the type and scope of the tests are de-
scribed in VDE 0701/0702 Part 1. The corresponding
national regulations must be adhered to.
2. Testing and resources
RGeneral tools for electricians and A/C mechanics
RDigital multimeter
RLoctite 577 for hoses
RCleaning medium (e.g. brake cleaner)
RCalibration weights for UV dye/oil bottles
(part number F 002 DG1 416)
RWeights for calibration of refrigerant scale - 6 kg
(part number F 002 DG1 650)

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Description | ACS 751/651 | 5ACS 751/651 | 5| 5 en
3. Description
3.1 ACS 751/651
3.1.1 Front view
0
2
4
68
10
0
5
10
15 20
25
30
35
12
HP
LP
14
!
2
ABC
3
DEF
6
MNO
ABC
123
8
TUV
7
PQRS
5
JKL
4
GHI
1
c
i
+
*
9
WXYZ
0
]
1 2 3
4
7
6
5
459897_18Nkv
8
9
10
Fig. 1: Front view
1 Handle
2 Human Machine Interface (HMI)
3 Top panel
4 Service hatch
5 HP quick coupler
6 Service hoses
7 LP quick coupler
8 Front wheel
9 Front service hatch
10 Inline filters
3.1.2 Rear view
459898_19Nkv
1
2
3
4
567
9
8
Fig. 2: Rear view
1 HMI support
2 Power switch
3 Left service hatch
4 Left panel
5 Rear panel
6. Rear wheel with brake
7 Power inlet
8 Power cable
9 Cable holder

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6 | ACS 751/651 | Descriptionen
3.2 Components
3.2.1 Mounting place
459898_21Nkv
12
3
4
5
6
7
9
8
10
11
12
13
14
15
Fig. 3: General overview
1 High pressure gauge
2 Low pressure gauge
3 Pressure manifold
4 Air purge manifold
5 Temperature sensor
6 Refrigerant cylinder
7 Oil separator
8 Compressor
9 Fan
10 Used oil bottle
11 Fresh oil bottle
12 Vacuum pump
13 UV dye bottle
14 Keypad
15 LCD
3.2.2 Human Machine Interface (HMI)
iC
!
HP
LP
1
2
3
5
4
6
7
1
2
3
4
5
6
7
8
9
*
+
0
ABC
123
]
459897_6Nkv
Fig. 4: ACS 751/651 HMI module
1 HP gauge
2 Status and warning light
3 LP gauge
4 LCD
5 Input keys
6 Selection and function keys
7 Printer

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Description | ACS 751/651 | 7ACS 751/651 | 7| 7 en
3.2.3 Refrigerant cylinder
459898_9Nkv
Fig. 5: Refrigerant cylinder overview
3.2.4 Pressure manifold
459898_13Nkv
Fig. 6: Pressure manifold overview
3.2.5 Vacuum pump
459898_7Nkv
Fig. 7: Vacuum pump overview
3.2.6 Compressor
459898_1Nkv
Fig. 8: Compressor overview
3.2.7 Fan
459898_14Nkv
Fig. 9: Fan overview

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8 | ACS 751/651 | Descriptionen
3.2.8 Human Machine Interface board (main board)
459898_29Nkv
1
2
3
456
8
9
10
11
7
Fig. 10: HMI Board (main board)
1 Connection to LCD
2 Coin battery CR2032
3 Connection to USB host (for firmware update)
4 Connection to LED
5 Connection to buzzer
6 Connection to keypad
7 Debug - Common port
8 I/O board communication port
9 Connection to printer data
10 Connection to printer power
11 Power from I/O Board
3.2.9 I/O board
459898_28Nkv
ACS-NP-IO-C-0030
12345
6
7
8
12 11 10
13
14
15
16
9
Fig. 11: I/O Board
1,2,3,4 Connections to scales
5 Connection to HMI board
6 Power to HMI
7 Power from SMPS
8,9Connection to solenoid valves
10 Connection to safety pressure switch
11 Connection to SMPS, Fan, Vacuum pump and compressor
12 Fuse
13 Connection to temperature sensor
14,15,16 Connection to pressure sensors

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Troubleshooting | ACS 751/651 | 9ACS 751/651 | 9| 9 en
4. Troubleshooting
4.1 By status messages
Error code Messages Actions
1001 RECOVERY
Service Timeout
RCheck for blockage in the vehicle A/C system.
RCheck for functionality of pressure sensor (PTA).
RCheck for compressor connections.
RCheck if internal parts of the manifold have blockage.
1002 RECOVERY
High pressure shutdown
RCheck for blockage in the vehicle A/C system.
RCheck for high pressure switch connection.
1003 RECOVERY
Used Oil bottle full
REmpty the used oil bottle.
RPerform scale reset.
RCheck for used oil bottle scale.
1004 RECOVERY
Refrigerant cylinder full
RWeight limit reached. Reduce quantity of refrig-
erant in internal refrigerant cylinder.
RScale is defective. Replace the scale.
RCheck for used oil bottle scale.
1005 RECOVERY
Used Oil Bottle Not Found
RCheck if the used oil bottle is disconnected. If the bot-
tle is disconnected, connect the bottle.
RCheck the used oil bottle scale.
2001 VACUUMING
High Pressure in vehi-
cle. Perform Recovery
The pressure is greater than 1400 mbar while vacuuming
RPress "Yes" to continue the recovery.
RPress "No" to abort the operation.
2002 VACUUMING
Leak detected
Leakage detected in the vehicle A/C system. Repair the vehicle A/C system.
3001 OIL RECHARGE
Service Timeout
RCheck the oil scale.
RCheck for blockage on the oil charge solenoid path.
3002 OIL RECHARGE
High pressure in vehi-
cle - Perform Recovery?
The pressure is greater than 1400 mbar while recharging.
RPress "Yes" to continue the recovery.
RPress "No" to abort the operation.
3003 OIL RECHARGE
High pressure in vehi-
cle - Perform Vacuuming?
The pressure is greater than 1400 mbar while recharging.
RPress "Yes" to continue the recovery.
RPress "No" to abort the operation.
3004 OIL RECHARGE
Insufficient Oil Quantity
ROil quantity is less than 30 ml. Refill the oil.
RReset the fresh oil bottle scale
RCheck the fresh oil bottle scale..
3006 OIL RECHARGE
Fresh oil Bottle Not Found
RCheck if the fresh oil bottle is disconnected. If the bot-
tle is disconnected, connect the bottle.
RCheck the oil bottle scale.
RCheck for blockage on the oil charge solenoid path.
4001 UV DYE RECHARGE
Service Timeout
RCheck for blockage in the hoses.
RCheck the oil scale.
RReplace the scale.
4002 UV DYE RECHARGE
High pressure in vehi-
cle - Perform Recovery?
The pressure is greater than 1400 mbar while recharging.
RPress "Yes" to continue the recovery.
RPress "No" to abort the operation.
4003 UV DYE RECHARGE
High pressure in vehi-
cle - Perform Vacuuming
The pressure is greater than 800 mbar while recharging.
RPress "Yes" to continue the vacuuming.
RPress "No" to abort the operation.
4004 UV DYE RECHARGE
Insufficient UV Dye quantity
RUV dye quantity is less than 30 ml. Fill the UV dye bottle.
RReset the UV dye bottle scale.
RCheck the UV dye scale.
RCheck for blockage on the oil charge solenoid path
4006 UV DYE RECHARGE
UV DYE Bottle Not Found
RCheck if the UV dye bottle is disconnected. If the bot-
tle is disconnected, connect the bottle.
RCheck for blockage on the oil charge solenoid path.
5001 R134aRECHARGE
Service Timeout
RCheck for blockage in the ACS 751/651.
RCheck if quick couplers are open.
RCheck for blockage in the hoses.
5002 R134a RECHARGE
Insufficient R134a quantity
Fill the internal refrigerant cylinder.
5003 R134a RECHARGE
Recharge Failed - Check Hoses
RCheck if HP and LP quick couplers are open.
RCheck if the HP and LP service hoses are blocked.
RCheck for blockage in the hoses

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10 | ACS 751/651 | Troubleshootingen
Error code Messages Actions
5004 R134a RECHARGE
High Pressure shutdown
RCheck the connection to high pressure switch
RCheck if the connection to the blue valve on the cylinder is open.
RCheck for blockage in the blue hose
5005 R134a RECHARGE
Refrigerant Cylinder Full
RWeight limit reached.
RReduce quantity of refrigerant in internal refrigerant cylinder.
RScale is defective. Replace the scale.
5006 R134a RECHARGE
High Pressure in Vehi-
cle - Perform Recovery?
RPress "Yes" to perform recharge.
RPress "No" to abort the operation.
5007 R134a RECHARGE
High pressure in vehi-
cle - Perform Vacuuming
RPress "Yes" to perform vacuuming.
RPress "No" to abort the operation.
7100 Safety Switch
High pressure shutdown
RAllow the unit to cool for 30 minutes and switch on the unit. Try re-
covery/hose drain. Check if the blue knob on the internal refrig-
erant tank is closed. Open the blue knob If it is closed.
RCheck if the electrical connections to the pressure switch are disconnected.
RCheck if there is blockage in the discharge tube/manifold/blue hose be-
tween the tank and valve block. Rectify if there is leakage.
RIn debug mode switch on CX and check if compressor is functioning.
7102 PSA
Sensor Connection Failed
RTemporarily interchange the PSA and PSV cable connection at the sen-
sor side. If the error is still with PSA sensor, then replace the top block.
RCheck the electrical continuity of the sensor cable including connector at both
ends for each individual wires. If continuity test fails, then change the cable.
RChange the I/O board.
7202 PST
Sensor Connection Failed
RTemporarily interchange the PST and PSV cable connection at the sen-
sor side. If the error is still with PST sensor, then replace the top block.
RCheck the electrical continuity of the sensor cable including connector at both
ends for each individual wires. If continuity test fails, then change the cable.
RChange the I/O board.
7302 PSV
Sensor Connection Failed
RTemporarily interchange the PSV and PSA cable connection at the sen-
sor side. If the error is still with PSV sensor, then replace the top block.
RCheck the electrical continuity of the sensor cable including connector at both
ends for each individual wires. If continuity test fails, then change the cable.
RChange the I/O board.
7402 Tank Temperature
Sensor Connection Failed
RCheck the electrical continuity of the sensor ca-
ble including connector at both ends.
RMeasure the resistance across two terminals of the temper-
ature sensor. If the measured resistance is found to be in-
finity or zero, change the temperature sensor.
RReplace the I/O board.
7403 Tank Temperature
Sensor Connection Failed
RCheck the electrical continuity of the sensor ca-
ble including connector at both ends.
RMeasure the resistance across two terminals of the temper-
ature sensor. If the measured resistance is found to be in-
finity or zero, change the temperature sensor.
RReplace the I/O board.
7501 R134a
Timeout
Replace the I/O board.
7502 R134a
Sensor Connection Failed
RMeasure the resistance across:
- Red-Black
- Green-White
If any of the two measurement shows inifinite resistance, change the load sensor.
RChange the I/O board.
7503 R134a
Sensor Connection Failed
RMeasure the resistance across
- Red-Black
- Green-White
If any of the two measurement shows inifinite resistance, change the load sensor.
RChange the I/O board.
7601 UV Dye
Timeout
Replace the I/O board.