Troubleshooting And Analysis; Faults During Recovery; Compressor Starts; Compressor Does Not Start - Bosch ACS 511 Repair Instruction

11. TROUBLESHOOTING AND
ANALYSIS
i
This section briefly describes the various faults, and
the components that can cause the faults.
!
Before carrying out any service intervention, re-
duce the ACS 511 pressure so that no refrigerant is
released.
11.1

Faults during recovery

11.1.1

Compressor starts

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EV3 and EV5 are closed for automatic self-cleaning.
The pressure at the pressure gages may not change.
1. Service hoses (T1, T2) are not connected to the
vehicle.
2. Close service quick-release couplings.
3. Open HP and LP valves on the ACS 511.
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If the pressure at the pressure gages decreases dur-
ing self cleaning, check whether EV3 and EV5 are not
supplied with power.
Power applied:
 Computer PCB (control PCB) defective.
"
Replace computer PCB (control PCB).
No voltage applied:
 Solenoid valve leaking.
"
Clean or replace solenoid valve.
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If the pressure at the pressure gages does not de-
crease after self cleaning, check whether EV3, EV5,
and EV10 are supplied with power.
Power applied:
 Solenoid valve defective.
"
Clean or replace solenoid valve.
No voltage applied:
 Computer PCB (control PCB) defective.
"
Replace computer PCB (control PCB).
Robert Bosch GmbH
TROUBLESHOOTING AND ANALYSIS | ACS 511 | 25
If the pressure at the pressure gages falls slowly:
1. Check filter (F 1).
If clogged, clean with compressed air (blow out).
2. Check function of valve VU2.
3. Valves V1 and V3 must be open.
4. Check expansion valve (3) with a pressure gage. Op-
erating pressure must be between 2,5 and 2,7 bar.
5. Check compressor (6).
ACS 511 ends the recovery phase but the pressure at
the pressure gages does not change.
1. Valves V1, V2, V3, and V4 must be open.
2. HP and LP valves must be open.
3. Check that pressure sensor (P1) functions properly.
11.1.2

Compressor does not start

1. Check fuses F 2 and F 3 (T 12.5 A) on control PCB.
2. Check whether 12 Volt (DC) is applied at the com-
pressor relay coil.
3. Check whether the compressor relay trips after
pressing the recovery key. It may be necessary to
replace the keypad or the control card.
4. Check whether 230 Volt is applied at the compressor
relay output pins.
 If no voltage is applied, the computer PCB is de-
fective and must be replaced.
 If voltage is applied, the current consumption
must be measured.
5. Measure current consumption. At 0 A or >=6 A the
compressor must be replaced.
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1 689 975 252 2019-05-15