FISCHER [CF] EASY User Manual page 76

3.3 Refrigeration piping connections
3.3.1 Refrigeration piping installation
WARNING
High pressure! Risk of personal injury! The units are pressurized with dry
air. Be careful when opening connections on a pressurized item.
WARNING
Low surface temperature! Danger of frostbite! The liquid line should be
insulated with 19 mm insulation thickness. Temperature could be as low as
–15°C.
IMPORTANT
Tubing quality! Installation contamination! All interconnecting piping
should be of refrigeration grade, clean, dehydrated and must remain capped
at both ends until installation. Even during installation, if the system is left for
any reasonable period of time (say 2 hours), pipes should be re-capped to
prevent moisture and contaminant from entering the system.
Connection sizes! Unsuitable refrigerant flow rate! Do not assume that
the service connection sizes on the unit (at the service valves) are in fact the
correct size to run your interconnecting refrigeration pipes. The service valve
sizes have been selected for convenience of installation and in some cases
(larger units) these may be considered too small. However for the very short
pipe run within our units these service connection sizes are adequate. All
interconnecting piping should be sized to satisfy the duty required.
IMPORTANT
No insulation on liquid line on CFLE units! Air moisture condensation
and lack of performance! Moisture will condensate on the liquid line and
cause water droplets. The liquid line can pick up additional heat from the
ambient which will adversely affect the sub-cooling desirable for the liquid
refrigerant before it enters the expansion valve. Insulate both the suction and
liquid interconnecting piping between the [ CF ] EASY unit and the
evaporator.
The pipe should be sized to ensure optimum performance and good oil return. The sizing must
also take into account the full capacity range through which this particular unit will need to
operate.
Pipe runs should be kept as short as possible, using the minimum number of directional
changes. Use large radius bends and avoid trapping of oil and refrigerant. This is particularly
important for the suction line. The suction line should ideally slope gently towards the unit.
Recommendation slope is 1/200 to 1/250. Upper and lower oil traps, double risers and reduced
pipe diameters may be required for suction lines where long vertical risers cannot be avoided.
All pipes should be adequately supported to prevent sagging which can create oil traps. The
recommended pipe clamp support distance is shown in Table 8 below:
Max distance between
Tube size
12.7 mm (1/2 inch)
16.0 mm (5/8 inch
22.0 mm (7/8 inch)
28.5 mm (1 1/8 inch)
Table 22: Maximum distance between 2 clamp supports
NOTE: It is strongly advisable to insulate both the suction and liquid interconnecting
piping between the [ CF ] EASY unit and the evaporator.
C6.1.6/0513-0515/E
2 clamp supports
1.20 m
1.50 m
1.85 m
2.20 m
23