D
–EIMAC00708-16EN - 68/76
If the refrigerant level is slightly low, the passage of bubbles can be seen through th e liquid pilot lamp. Replenish the
circuit as described in the replenishment procedure.
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.
Refrigerant replenishment procedure
If the machine has exhausted the refrigerant, it is necessary first of all to establish the causes, before carrying out any
replenishment operation. The leak must be looked for and repaired. Oi l 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 searching device is required to find the position
of small leaks.
Add refrigerant to the system through the service valve located on the intake pipe or through the Schrader valve located
on the evaporator entry pipe.
The refrigerant can be added under any load condition between 25 and 100% of the circuit. Intake overheating must be
between 4 and 6°C.
Add enough refrigerant to fill the liquid pilot lamp entirely, until the passage of bubbles inside stops. Add an extra 2
3 kg
of refrigerant as a reserve, to fill the undercooler if the compressor is operating at 50
– 100% load.
Check the undercooling value by taking the liquid pressure and the liquid’s temperature near the expansion valve. The
undercooling value must be between 4 and 8 °C and between 10 and 15°C machines with an economiser. The
undercooling value will be lower 75 to 100% of the load and above 50% of the load.
With ambient temperature above 16°C, all ventilators should be on.
A system overcharge will entail a rise in the compressor’s discharge pressure, owing to excessive filling of the condenser
section pipes.
Table 27 - Pressure/ Temperature
Pressure/Temperature table for HFC-134a
°C
Bars
°C
Bars
°C
Bars
°C
Bars
-14
0.71
12
3.43
38
8.63
64
17.47
-12
0.85
14
3.73
40
9.17
66
18.34
-10
1.01
16
4.04
42
9.72
68
19.24
-8
1.17
18
4.37
44
10.30
70
20.17
-6
1.34
20
4.72
46
10.90
72
21.13
-4
1.53
22
5.08
48
11.53
74
22.13
-2
1.72
24
5.46
50
12.18
76
23.16
0
1.93
26
5.85
52
13.85
78
24.23
2
2.15
28
6.27
54
13.56
80
25.33
4
2.38
30
6.70
56
14.28
82
26.48
6
2.62
32
7.15
58
15.04
84
27.66
8
2.88
34
7.63
60
15.82
86
28.88
10
3.15
36
8.12
62
16.63
88
30.14
