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7-6. General Maintenance
Non-periodical maintenance
• Maintenance of the compressor bearing and the gear
The core of maintaining bearing and the gear can be said adequate lubrication. Preserve the recommended oil
amount, temperature and pressure by using the right level of oil. Do a thorough maintenance check-up on the lubri-
cation system periodically. To inspect the bearing, the compressor must be completely disassembled.
To take out the bearing and to inspect it, a high technology specialist is needed. Excessive abrasion can occasion-
ally be detected by excessive vibration or by the bearing's temperature.
• Refrigerant leak inspection
HFC-134a has higher pressure than air in room temperature, so it requires the refrigerant leak test utilizing elec-
tronic detector, halogen leak detector or soapy water.
If the refrigerant leak is overall the entire chiller with large volume, immediately stop using the system and fix it
first. If the refrigerant was lost or the machine has been opened during the service period, the chiller itself or re-
lated tank must be taken leak test by adding pressure.
Refer to 5-5-2 for leak inspection.
Charging refrigerant and leakage test
- Refrigerant characteristics
Usage refrigerant is HFC-134a.
HFC-134a evaporates at -26°C in normal air pressure, so it shall be stored in a pressured container or storage tank.
Refrigerant has almost no smell when it is mixed with air, and it is non-combustible in air pressure.
!
CAUTION
The refrigerant HFC-134a dissolves oil and some non-metallic material, dries skin, and makes oxygen deficiency resulting in suffoca-
tion at high concentration. Thus be very careful not to inhale or touch by hand or eye contact when you handle the refrigerant.
<Characteristics Table>
Molecule formula
Molecule amount
Boiling point (air pressure)
Freezing point
Critical temp.
Critical pressure
Density of saturated fluid (25°C)
Specific volume of saturated vapor (25°C)
Specific heat ratio, vapor (25 °C, air pressure)
Evaporative latent heat (25°C)
Table 60. The property of HFC-134a
°C
°C
°C
2
kg/cm
.A
3
kg/m
3
m
/kg
kcal/kg
123
CH
F-CF
2
3
102.031
- 26
- 101
101
41.5
1206
0.031
1.1186
42.54
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