5
RAU-SVX01B-E4
Refrigerant lines
Calculating and fixing the capacity
of refrigerant lines is necessary to
assure the oil return to the
compressor, avoid refrigerant phase
changes and limit pressure drop.
Liquid lines
Calculate capacity of liquid line, as
per the following criteria.
1. Maximum load operating
conditions.
2. To avoid any evaporation risk:
-
Consider the vertical risers
-
Maximum pressure drop must
not exceed 1 to 2°C
3. Liquid circulation speed in a 0.5
to 2m/s range.
Discharge lines
Discharge lines should be calculated
to obtain the gas displacement
speed in horizontal and vertical lines
required to drive compressor oil.
Determine diameter of discharge
lines as per the following criteria.
1. Speed above 2,5 m/s horizontally.
(Consider minimum speed at
minimum load)
2. Speed above 5,0 m/s vertically
(Vertical risers, consider speed at
minimum load)
3. Maximum speed 20 m/s.
4. Horizontal pipe run must be
pitched of 1cm/m in the same
direction as the refrigerant
circulation
5. An oil trap is necessary for
vertical risers greater than 3m.
For major elevations add an
intermediate oil trap every 5m.
6. Maximum pressure drop between
20 to 50 kPa
7. Install a filter drier adapted to
refrigerant capacity.
Insulation of refrigerant lines
Insulate refrigerant lines from
building itself to avoid transmission
to building structure of vibrations
normally caused by pipework.
Also avoid bypassing the unit's
damping system by fixing the
refrigerant lines or the electrical
ducts very rigidly.Vibrations may
propagate into building structure
through rigidly fixed refrigerant
lines.
Pressure tests. Leak detection
During operations, take the following
precaution:
1. Neither oxygen nor acethylene
should be used instead of
refrigerant and nitrogen to detect
leaks, otherwise a violent
explosion may occur.
2. Always use valves and
manometers to check the test
pressure in system. Excessive
pressure may either cause pipes
to rupture, damage unit, or cause
an explosion, causing possible
physical injury.
Carry out liquid line and hot gas line
pressure tests in accordance with
current standards.
The test pressures applied to the
liquid line and the hot gas suction
line must comply with the country's
standards.
Caution:
Do not go more than 0.7
bar above the high pressure switch
setpoint.
Introduce enough refrigerant into
circuit for 85 to 100 kPa pressure,
pump-injecting dry nitrogen, and
raise pressure to 100 kPa. Search for
possible leaks using detector. This
operation should be carried out with
great care throughout the system.
If leaks are detected, reduce system
pressure, and repair defective
component. Repeat test process, to
check that the repair can withstand
rated pressure.
Caution:
Unit is delivered with a
refrigerant holding charge and
isolating valves.
Содержание RAU-SVX01B-E4
Страница 27: ...27 RAU SVX01B E4 Notes...
