Procedure To Replenish Refrigerant; Table 5 - Pressure/ Temperature - Daikin EWYD-BZ Series Installation, Maintenance & Operation Manual

The machine can be replenished under any stable load condition (preferably between 70 and 100%) and under any
ambient temperature condition (preferably above 20°C). The machine should be kept running for at least 5 minutes to
allow the fan steps, and thus the condensation pressure, to stabilise.
Note: When the load and the number of active fans vary, so does the subcooling and it requires several minutes to
stabilise again. However, the subcooling should not come below 3°C under any condition. Also, the subcooling value can
change slightly as the water temperature and the suction superheating vary. As the suction superheating value
decreases, there is a corresponding decrease in subcooling.
One of the following two scenarios can arise in a machine without refrigerant:
1 If the refrigerant level is slightly low, suction superheating is always higher than normal and the valve is wide
open. Replenish the circuit as described in the replenishment procedure.
2 If the gas level in the machine is moderately low, the corresponding circuit could have some low-pressure stops.
Replenish the corresponding circuit as described in the replenishment procedure.
Note: The liquid receiver must be completely full in heat pump mode when the machine contains the correct charge.

Procedure to replenish refrigerant

1. If the machine has lost refrigerant, it is necessary to first establish the causes before carrying out any replenishment
operation. The leak must be found and repaired. Oil stains are a good indicator, as they can appear in the vicinity of
a leak. However, this is not necessarily always a good search criterion. Searching with soap and water can be a
good method for medium to large leaks, while an electronic leak detector is required to find small leaks.
2. Add refrigerant to the system through the service valve located on the suction pipe or through the Schrader valve
located on the water heat exchanger inlet pipe.
3. The refrigerant can be added under any load condition between 25 and 100% of the system capacity. Suction
superheating must be between 4 and 6°C.
4. Add enough refrigerant to fill the liquid receiver completely in heat pump mode.
5. Check the subcooling value by reading the liquid pressure and the liquid temperature near the expansion valve. The
subcooling value must be between 4 and 8°C and between 10 and 15°C for the machines with an economiser. With
reference to the above mentioned values, the subcooling will be lower at 75÷100% load and higher at 50% load.
6. When the ambient temperature is above 16°C, all fans should be on.
Overcharging the system will entail a rise in the compressor's discharge pressure, owing to excessive filling of the
condenser section pipes.

Table 5 - Pressure/ Temperature

Pressure/Temperature table for R-134a
°C bar °C
-14 0,71 12
-12 0,85 14
-10 1,01 16
-8 1,17 18
-6 1,34 20
-4 1,53 22
-2 1,72 24
0 1,93 26
2 2,15 28
4 2,38 30
6 2,62 32
8 2,88 34
10 3,15 36
bar °C bar
3,43 38 8,63
3,73 40 9,17
4,04 42 9,72
4,37 44 10,30
4,72 46 10,90
5,08 48 11,53
5,46 50 12,18
5,85 52 13,85
6,27 54 13,56
6,70 56 14,28
7,15 58 15,04
7,63 60 15,82
8,12 62 16,63
°C bar
64 17,47
66 18,34
68 19,24
70 20,17
72 21,13
74 22,13
76 23,16
78 24,23
80 25,33
82 26,48
84 27,66
86 28,88
88 30,14
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