Refrigerant Cylinder; Replacing The Refrigerant Cylinder; Air Purging - Bosch ACS 751 Repair Instructions

9.

Refrigerant cylinder

9.1

Replacing the refrigerant cylinder

Warning - Danger of frostbite!
During repair work on the ACS 751/651
refrigerant in liquid or gaseous form can
escape and cause frostbite to the body.
¶
Close valves on the refrigerant cylinder.
¶
Wear protective goggles.
¶
Wear protective gloves.
Fig. 26: Refrigerant cylinder
1. Perform hose drain.
2. Switch off the ACS 751/651.
3. Disconnect the mains connection.
4. Open the front and rear panel (chap. 6.2, 6.3)
5. Close the red and blue knobs on the Y-valve of the
refrigerant cylinder..
6. Disconnect the hydraulic connections to the end
connections of the Y-valve.
7. Disconnect the solenoid valve connections to the
cylinder.
8. Disconnect the pressure sensor connectors on the
air purge manifold to the I/O board.
9. Disconnect the temperature sensor connection to
the I/O board.
10. Open the 2 locking bolts of the cylinder.
11. Place the cylinder outside the ACS 751/651 unit.
12. Place the new cylinder in position.
13. Tighten the locking bolts for the cylinder.
14. Route the red and blue hoses to the cylinder.
15. Restore the hydraulic connections to the cylinder.
16. Restore all the electrical connections.
17. Open the red and blue knobs on the cylinder.
18. Connect the power cable to the mains supply.
19. Switch on the mains supply.
Robert Bosch GmbH
Refrigerant cylinder | ACS 751/651 | 25
20. Start the ACS 751/651 in the debug mode
(Chap. 4.3)
21. Calibrate the scale of the refrigerant tank
(Chap. 5.12).
22. Select RE and HL and press .
23. Observe the value of the pressure.
? The value of PTV should be more than
600 mbar.
24. Select VC and VISO. Press .
25. Deselect VC and VISO after 3 minutes.
? The value of the PTV should decrease to less
than 200 mbar.
26. Observe the value of PTV for 1 minute.
? The value of the PTV should not increase beyond
350 mbar.
i
If the value of PTV increases beyond 350 mbar,
check, switch off the ACS 751/651 and check the
hydraulic connections.
27. Check the tare weight of the cylinder by pressing
the i key.
Unit type Tare weight of refrigerant cylinder
ACS 651 / 751 10300 g
Tab. 1: Tare weight of refrigerant cylinder
28. Deselect RE and HL.
29. Close the front and rear panel.
i
Ensure that the cylinder is filled with the refrigerant
before vehicle A/C service.
9.2

Air purging

1. Open the right service hatch.
2. Pull the metal ring on the safety valve for two minutes
to purge the non-condensable gases.
3. Close service hatch.
ACS 751/651 | 25 | 25 en
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1 689 975 223 2013-10-21