3 Piping work and
refrigerant charge
96
SMGB0077 rev.0 - 01/2013
3.4 Copper refrigerant pipe
3.4.1 Three principles on work with refrigerant pipes
The basic refrigerant pipe installation work must be carried out paying particular attention to avoid the inîš¿ltration of humidity
or dust while working with the refrigerant piping. Otherwise, rust may appear inside the system or the units and cause
serious faults.
Therefore, all work carried out on the copper pipes for refrigerant must follow the three principles described below.
Principle Cause of the fault Possible fault Preventive measure
1. Absence of humidity
Ensure the atmosphere re-
mains totally dry
• Water inltration due to
insufîš¿cient protection on
the ends of the pipes.
• Condensation on the
inside of the pipes.
• Insufcient vacuum.
Ice on the inside of the pipe,
on the expansion valve (water
obstruction)
+
Absorption of oil humidity and
oxidation
↓
Filter clogging, insulation and
compressor fault
Pipe protection:
1. Seal the ends of the pipes.
2. Protect and insulate the ends
of the pipes.
↓
Wash
↓
Vacuum dry
(*)
2. Cleaning
Absence of dust on the inside
of the piping
• Dust or other elements
entering the ends of the
pipes.
• Film of rust formed
during brazing without
nitrogen injection.
• Insufcient nitrogen
wash after brazing.
Expansion valve, capillary tube
and îš¿lter clogging.
Oil oxidation.
Compressor fault
↓
Compressor fault, insufîš¿cient
cooling or heating
Pipe protection:
1. Fit caps to the ends of the
pipes.
2. Protect and insulate the ends
of the pipes.
↓
Wash
3. Absence of leaks
There must be no leaks
• Brazing fault.
• Flaring fault and
insufîš¿cient torque.
• Insufcient torque on
compressor connectors.
Lack of refrigerant
Drop in performance
Compressor fault
Oil oxidation.
↓
Compressor overheating
Carry out basic brazing work
carefully
↓
Carry out basic aring work
carefully
↓
Carry out basic connection
work carefully
↓
Airtight test
↓
Preserving of vacuum in the
installation
(*)
One gram of water becomes approximately 1000 l of steam at 1 Torr. (1 Torr = 1 mmHg = 133.32 Pa). Therefore, a long
time must be spent on vacuum work using a small pump.
3.4.2 General information on copper refrigeration pipes
C A U T I O N
• The copper pipe used in the refrigeration installations is different to the copper pipe used in installations
carrying domestic or heating water.
• The copper pipe for refrigeration installations is especially treated for outdoors and indoors. The interior
surfacenishmakesiteasierforthegasrefrigeranttocirculateandwithstandstheactionofthelubricantoil
applied to outdoor equipment.
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