Refrigeration Maintenance 10-9
The following charge procedure is the same for all units with the exception of the micro-channel units equipped with MTV
(Mechanical Throttling Valve).
This unit requires that all panels be closed and installed prior to carrying out the controlled refrigerant level check. With this
unit there is a possibility that the auxiliary receiver can become cooler than the main receiver and thus the liquid can migrate
to the cooler auxiliary receiver.
SLX, SLXe, SLXi SPECTRUM charging procedure:
1. Install a calibrated gauge manifold on the unit and leak check the unit before charging with refrigerant.
2. Recover residual refrigerant charge and evacuate the system completely.
3. Make a quick calculation of the approximate required refrigerant charge. Refer to Table 1 for initial charge calculations.
4. Liquid charge unit with the exact calculated amount from step 3 utilising weighing scales to ensure accurate measurement.
Note: Please take note of your refrigerant type (label on outside of unit), and make sure not to cross-contaminate.
5. For Category B unit, close all doors on unit and ensure all unit panels and skins are securely attached.
6. Run unit in high speed cool with a set point of -20?C in all zones and with any separation walls stowed in the open position.
Note: Carry out manual defrost of remote evaporators and then host unit evaporator at -15
°
C to ensure all ice is cleared from
all evaporators.
7. Maintain unit running in high speed cool and check refrigerant level. Cover condenser to raise discharge pressure to
approximately 325psig to 350psig (22 Bar to 23 Bar gauge). Ball in receiver sight glass should be between ⅓ and ½ full, if
the ball is not floating add charge at 0.25kg increments until the ball floats.
8. For Category B unit, after the first additional 0.25kg is added, all doors should be closed and high speed cool should be
maintained. Proceed as per step 7. Wait 5 minutes. Check refrigerant level by opening doors momentarily.
9. If ball is not floating, close doors, uncover condenser and proceed to add more refrigerant according to step 7 until the ball
floats.
10. If the recommended charge level is exceeded by 1kg, this indicates that the unit may now be overcharged and the installation
should be checked for possible problems.
11. Once system is charged and prior to placing the unit into service, ensure to recover remaining refrigerant from the hoses of
the gauge manifold set,
ensure the correct refrigerant charge is entered into the refrigerant charge decal on the frame near the
serial plate. This must be filled in so the next technician knows the quantity required for the system. Please ensure that the
installed date information is also entered.
Category A Category B Category C
Condenser Finned-tube Micro-channel Micro-channel
Throttle valve Mechanical Mechanical Electronic
Receiver 1 2 2
Charge (approximate)
7.5kg Host +
0.75kg (per S-2) or
1.0kg (per S-3) for
each evaporator,
plus
0.13kg/m of
refrigerant tube
6kg Host + 0.75kg
(per S-2) or
1.0kg (per S-3) for
each evaporator,
plus
0.13kg/m of
refrigerant tube
6kg Host + 0.75kg
(per S-2) or
1.0kg (per S-3) for
each evaporator,
plus
0.13kg/m of
refrigerant tube
Charging procedure
Standard All doors must be closed Standard
Table: Refrigerant charges for unit configuration categories.
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