Emerson Copeland EazyCool ZXME020E Application Manuallines page 41

4 Starting up & operation
Before commissioning, ensure that all valves on the condensing unit are fully opened.
4.1 Evacuation
CAUTION
System pressure below atmospheric pressure! Compressor damage!
Never energize the unit/controller without minimum refrigerant system charge.
There is a risk of malfunction of the controller in deep vacuum operation which
can cause compressor damage.
IMPORTANT
The evacuation procedure is based upon achieving an actual system vacuum
standard and is NOT TIME DEPENDENT! The installation has to be
evacuated with a vacuum pump before commissioning. Proper evacuation
reduces residual moisture to 50 ppm. The installation of adequately sized
access valves at the furthest point from the compressor in the suction and
liquid lines is advisable. The system must be evacuated down to less than 3
mbar. If required break the vacuum with dry nitrogen. Pressure must be
measured using a vacuum pressure gauge on the access valves and not on
the vacuum pump. This serves to avoid incorrect measurements resulting from
the pressure gradient along the connecting lines to the pump.
4.2 Charging procedure
4.2.1 Refrigerant charging procedure
IMPORTANT
Inadequate charge! Overheating! The Scroll compressor design requires
system charging as quickly as possible with liquid refrigerant into the liquid
line. This will avoid running the compressor under conditions whereby
insufficient suction gas is available to cool not only the motor but also the
scrolls. Temperature builds up very quickly in the scrolls if this is not done.
Service valve closed! Compressor damage! Do not charge the unit with
vapour (gas). The suction service valve must not be fully closed at any time
when the compressor is running. To do so would cause damage to the
compressor in the same manner as explained above. This valve is provided
for ease of connection and for the fitting of service gauges without removing
the unit panel.
IMPORTANT
Absence of insulation on the liquid line in ZXLE units! Air moisture
condensation and lack of performance! Moisture will condensate on the
liquid line and cause water droplets. The liquid line can pick up additional heat
from the ambient which will adversely affect the sub-cooling desirable for the
liquid refrigerant before it enters the expansion valve. Both the suction and
liquid interconnecting piping between the ZX unit and the evaporator should
be insulated to avoid condensation.
Pre-charging must be carried out with liquid refrigerant through the service valve on the liquid line. It
is advisable to pre-fill the suction side with a partial charge to avoid vacuum operation. Further
charging can be carried out by carefully filling refrigerant through the suction line while
simultaneously checking the sight glass.
NOTE: In order to meet the requirements of the Ecodesign Directive 2009/125/EC with regard
to efficient system operation, ensure the refrigerant charge is sufficient.
NOTE: During the charging process on ZXLE units, the liquid line (outlet of the unit)
temperature must be checked. The charging is sufficient when the liquid line temperature
does not decrease significantly anymore and when the subcooling reaches approximately
25-35K.
36 C6.1.6/0117-1017/E