D-EIMWC01008-16_03EN - 23/35
6.1.3
Charging the unit
1. Perform an integral pre-
start inspection like explained in “BEFORE STARTING”.
Carefully perform all required procedures like explained in chapters from which is referred to in
chapter “BEFORE STARTING”, but do not start the unit.
It is also necessary to read the operation
manual delivered with the unit. This will contribute to understand the operation of the unit and its
electronic controller.
Pre-charge of refrigerant without operation of the unit
2.
Use the 1/4” SAE Flare stop valve on the filter drier to pre-charge the unit with the complete calculated pre-charge.
3. Do not operate the compressor for pre-charging, this to avoid compressor damage! After completion of procedure
step 2,
perform an “initial start” test:
a. Start the compressor and wait for the compressor to go through the star/delta. Carefully check during
start-up:
▪
that compressor is not producing any abnormal noise or vibration;
▪
that high pressure rises, and low pressure drops within 10 seconds after to evaluate if the
compressor is not operating in reverse due to wrong wiring;
▪
that no safeties are activated.
b. Stop the compressor after 10 seconds.
Fine-tuning of refrigerant charge while unit is in operation
4.
Use the 1/4” SAE Flare valve on the suction for fine-tuning of the refrigerant charge and make sure to charge the
refrigerant in its liquid state.
a. For fine-tuning of the refrigerant charge, the compressor must operate at full load (100%).
b. Verify the superheat and subcooling:
▪
superheat must be between 3 and 8 K
▪
subcooling must be between 3 and 8 K
c.
Verify the oil sight glass. Level must be within the sight glass.
d. Verify the liquid line sight glass. It should be sealed and not indicate moisture in the refrigerant.
e. As long as the liquid-line sight glass is not sailed, add refrigerant in steps of 1 Kg and wait until the unit
runs in stable conditions. Repeat the complete procedure step 4 until the liquid line sight glass is sealed.
The unit must have the time to stabilize which means that this charging has to be done in a smooth way.
5. Note down the superheat and subcooling for future reference.
Fill out the total refrigerant charge on the unit nameplate and on the refrigerant charge label supplied with the product.
NOTE
Take care for contamination of the remote condenser in order to avoid blocking of the system. It is impossible for
the manufacturer to control the contamination of the “foreign” condenser of the installer. The unit has a strict contaminatio n
level.
6.2
Refrigerant piping design
The system can be configured in any of the main arrangements as shown in Figure 5, Figure 6 and Figure 7. The
configuration and its
associated elevation, along with the total distance between the chiller and the air -cooled condenser are important factors
in determining the liquid line and discharge line sizes. This will also affect the field refrigerant charges. Consequently,
there are physical limits that must not be violated if the system is to operate as designed.
1. The total distance between the chiller and the air-cooled condenser should not exceed 60 equivalent meters
2. Liquid line risers must not exceed 3 meters in height from the condenser liquid line connection.
3. Discharge line risers cannot exceed an elevation difference greater than 30 actual meters.
