Technical data

REPLACE COMPONENTS
6 720 803 687 (2012/11) 77
PREPARING THE EXTERNAL UNIT
▶ Connect a pressure gauge to the service port [3] (Fig. 32, page 29) to
check the pressure in the refrigerant system whilst pumping the
refrigerant back to the external unit.
▶ Remove caps from the shut-off valve on the pipe work for liquid and
gaseous refrigerant ( Fig. 32, page 29).
▶ Turn Allen screw clockwise to close the shut-off valve on the pipe work
for liquid refrigerant.
▶ Remove the three top cover fixing screws, and lift the top cover away.
Fig. 71 Lifting the external unit top cover away
PUMPING REFRIGERANT BACK INTO THE EXTERNAL UNIT
▶ Switch on the power supply to the external unit and the hybrid
manager.
▶ Press “SWP” on the external unit PCB.
The fan and compressor will both start running and begin pumping
refrigerant back into the external unit.
LED1 and LED2 on the external unit PCB light up.
The refrigerant is pumped back to the external unit via the pipe work
for gaseous refrigerant.
As soon as the unit automatically stops (about 2 to 3 minutes after start):
▶ Quickly close the gas shut-off valve.
This prevents refrigerant from flowing back into the refrigerant
circuit.
To ensure that the refrigerant has been completely pumped down:
▶ Check the pressure in the refrigerant circuit at the pressure gauge on
the service port.
The pressure must be 0 Pa (0 mbar (a)).
If the external unit is switched off before pump down is complete, or if
the refrigerant was not successfully pumped back into the external unit
(compressor does not run for 2 to 3 minutes):
▶ Completely open shut-off valve on the pipe work for gaseous
refrigerant.
▶Wait 3 minutes.
▶ Pump back the refrigerant again.
If the external unit stopped normally:
▶ Disconnect the power supply of the external unit (circuit breaker) and
the hybrid manager (switch off).
▶ Replace the top cover on the external unit and secure with the four
screws.
▶ Return the DIP switches at the interface to the external unit in the
hybrid manager into their standard setting.
Fig. 72 DIP switches in normal position
▶ Fit the covers onto the control unit enclosure and control module, flip
up the control unit enclosure and fit the cover of the hybrid manager.
▶ Fit caps to the shut-off valves on the pipe work for liquid and gaseous
refrigerant.
11.2 REMOVING THE CASING FROM THE EXTERNAL UNIT
To remove the service cover, top, front and rear parts, proceed as
follows:
▶ Remove 3 screws (M 10x4) from the top section of casing [1].
▶ Remove top section [1].
▶ Remove screw (M 10x4) from service cover [3].
▶ Pull service cover [3] forward and remove.
▶ Remove 9 screws (M 10x4) from the front section of cover [4].
▶ Remove front section [4].
▶ Remove 7 screws (M 10x4) from the rear section of casing [2].
▶ Remove rear section [2].
Fig. 73 Removing casing from the external unit
Only start refrigerant collection after the external unit
has not operated for a period of 5 minutes or longer.
WARNING: Risk of injury due to moving parts!
When the “SWP” button is pressed the fan will
immediately start to run.
▶ Ensure no loose clothing or tools can fall into or get
caught in the fan.
▶ Keep hands clear.
CAUTION: Risk of injury from poisonous gases!
Escaping refrigerant coming into contact with a naked
flame will produce poisonous gases.
▶ Never release refrigerant to the atmosphere.
6 720 646 970-44.2ITL
6 720 646 970-45.2ITL
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