Bosch ACS 251, Original Instructions Manual, Page: 17 / 24

F 002 DG9 425 2014-03-20
|
Bosch Limited
Program description | ACS 251 | 17 en
9. Turn the HP/LP quick couplers in the counterclock-
wise direction and disconnect from the service con-
nections on the vehicle A/C system.
10. Press

.
11. Press

to start draining the refrigerant from the
hoses.
 Once the refrigerant is drained, a summary
screen is displayed.
"
The servicing of the vehicle A/C system is complete.
6.8 Additional services
6.8.1 Refrigerant top up
If there is a decrease in the quantity of refrigerant in
the vehicle A/C system, an additional quantity can be
added.
Before doing a top up, the quantity of refrigerant al-
ready present in the car A/C system is not known. In
such a scenario, topping up might result in overcharging
of the refrigerant. A top up should be performed only
after ascertaining the quantity of refrigerant already
present in the car A/C system. Else, a complete A/C
service should be performed.
1. In the main menu, select " A/C Services " and press
E . Alternatively, press the MENU button on the
keypad.
2. Select " Add. Services " and press E .
3. Select " R134a Top Up " and press E .
4. Connect the LP coupler to the service connection on
the vehicle A/C system and press

.
5. Start the vehicle and switch on the A/C. Press

.
6. Enter the quantity of refrigerant to be topped up.
Press

.
i
The valid top up quantity range is between 20 and
100 grams.
7. Press

.
 The refrigerant top up starts. At the end of the
service,
Hose Drain menu is displayed.
8. Turn the HP/LP quick couplers in the counterclock-
wise direction and disconnect from the service con-
nections on the vehicle A/C system.
9. Press

.
10. Press

to start draining the refrigerant from the
hoses.
 Once the refrigerant is drained, a summary
screen is displayed.
"
You have successfully topped up the refrigerant in the
vehicle.
6.8.2 Hose drain
After every recharge / top up, some quantity of refriger-
ant is left in the hoses. It is necessary to drain the re-
frigerant from the hoses.
1. In the main menu, select " A/C Services " and press
E . Alternatively, press the MENU button on the
keypad.
2. Select " Add. Services " and press E .
3. Select " Hose Drain " and press E .
 The Hose Drain menu is displayed.
4. Turn the HP/LP quick couplers in the counterclock-
wise direction and disconnect from the service con-
nections on the vehicle A/C system.
5. Press

.
6. Press

to start draining the refrigerant from the
hoses.
 Once the refrigerant is drained, a summary screen
is displayed.
"
The servicing of the vehicle A/C system is complete.
6.8.3 A/C performance test
The health of the vehicle A/C system can be monitored
by checking the pressure and temperature at a specific
location as recommended by the vehicle manufacturer.
The A/C performance can be done before or after ve-
hicle A/C service.
1. In the main menu, select " A/C Services " and press
E . Alternatively, press the MENU button on the
keypad.
2. Select " Add. Services >> " A/C Test ".
3. Press E .
4. Connect the HP and LP service hoses to the respec-
tive service connections on the vehicle A/C system.
Press

.
5. Start the engine with the vehicle gear lever turned to
Neutral .
6. Switch on the vehicle A/C to Maximum (cooling to
maximum). Press

.
7. Press

.
8. Perform the A/C system test based on either of the
following as per the vehicle manufacturer’s recom-
mendation:
$
Grill temperature
$
HP and LP pressure gauge readings
9. After the A/C system test is complete, turn off the
engine and the vehicle A/C system. Press

.
10. Disconnect the HP hose from the HP service con-
nection of the vehicle A/C system. Press

.
11. Follow the instructions displayed.
12. Press E .
 The A/C TEST HOSE DRAIN menu is displayed.
13. Detach the LP coupling and press

.
14. Press

to start the hose drain.
"
Upon completion of the hose drain, the A/C perfor-
mance test is complete.