Panasonic OCU-CR1001VF Installation Instructions Manual page 34

Adjustment during Operation
Adjusting Refrigerant Quantity of the Refrigeration Unit
During determination of refrigerant quantity, temperature setting of all Unit coolers/Display cases needs to be set to the
lowest temperature without activation of the thermostat for making the refrigeration unit operating continuously.
(1) Method of determining refrigerant quantity
Check the operation condition of the refrigeration unit by the following method, and adjust the refrigerant quantity to
the appropriate value according to Table 3 (Determination criteria of refrigerant quantity).
1) Check that the suction gas temperature is 18°C or below.
2) Check that the superheat of the suction gas temperature is 10 K or greater.
3) Check if the high pressure has been set to the standard high pressure (Table 2).
4) Check if the gas cooler outlet temperature is +2 K to +5 K for the ambient temperature.
The method of checking each temperature and pressure should comply with Table 1 and the value should be
confirmed with the digital display.
Table 1 Method of checking each temperature and pressure
Reference item
Suction
temperature
High pressure
Gas cooler outlet SW13-7 ON
temperature (all other OFF)
Table 3 Determination criteria of refrigerant quantity
Gas cooler outlet
temperature
High pressure
High
Standard
Low
: Refrigerant overcharge,
▲
: Perform continuous operation and monitor the condition.
(2) Refrigerant quantity adjustment
1) Shortage of refrigerant (when charging additional refrigerant)
• Perform cooling operation and charge additional refrigerant via the access port of the low pressure service valve.
• Adjust valve opening during slow charging operation to avoid frosting beyond the refrigerant service valve.
• Guideline of charging rate of refrigerant is 20 g per 5 seconds.
Note: Rapid refrigerant charging may lead to a compressor failure.
2) Overcharging of refrigerant (when releasing the refrigerant)
• Release the refrigerant via the access port of the low pressure service valve.
• Open the valve very slowly. Use caution for oil leak out.
• As CO refrigerant is heavier to air, use caution for gas stagnation.
2
3) After completing refrigerant adjustment, close the access port of the low pressure service valve.
When charging refrigerant, refer to the Engineering Service Manual "Refrigerant Charging
Caution
Procedure".
DIP switch Rotary switch
SW 13 (knob) SW 11
All OFF Suction (吸入)
All OFF Pressure (圧力)
OFF
(Press
▲
Less than "Ambient
temperature +2 K"
▲
: Appropriate,
Table 2 Standard high pressure
Ambient
temperature
0 °C or below
5 °C
10 °C
3 times)
15 °C
20 °C
25 °C
30 °C
35 °C
"Ambient temperature
to
"Ambient temperature
▲
: Refrigerant shortage,
Evaporating Temp. Evaporating Temp.
≤ -20 °C > -20 °C
High pressure
3.4MPa 3.4MPa
3.9MPa 3.9MPa
4.4MPa 4.4MPa
5.0MPa 5.0MPa
5.6MPa 5.6MPa
7.5MPa 8.0MPa
8.5MPa 9.0MPa
9.1MPa 9.6MPa
+2 K"
Greater than "Ambient
temperature +5 K"
+5 K"
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