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way as to cause rotation in the reverse direction, it is important to include notices and
instructions in appropriate locations on the equipment to ensure proper rotation direction
when the system is installed and operated.
Observing that suction pressure drops and discharge pressure rises when the compressor is
energized allows verification of proper rotation direction. There is no negative impact on durability
caused by operating three-phase Copeland scroll compressors in the reverse direction for a short
period of time (under one hour) but oil may be lost. Oil loss can be prevented during reverse rotation
if the tubing is routed at least 15 cm above the compressor. After several minutes of operation in
reverse, the compressor protection system will trip due to high motor temperature. The operator will
notice a lack of cooling. However, if allowed to repeatedly restart and run in reverse without correcting
the situation, the compressor will be permanently damaged.
All three-phase scroll compressors are identically wired internally. Therefore, once the correct
phasing is determined for a specific system or installation, connecting properly phased power leads
to the identified compressor terminals will ensure proper rotation direction.
5.9
Starting sound
During the very brief start-up, a clicking sound resulting from the initial contacting of the spirals is
audible and is normal. Due to the design of the Copeland scroll compressors, the internal
compression components always start unloaded even if system pressures are not balanced. In
addition, since internal compressor pressures are always balanced at start-up, low voltage starting
characteristics are excellent for Copeland scroll compressors.
5.10 Deep vacuum operation
CAUTION
Vacuum operation! Compressor damage! Copeland scroll compressors in
refrigeration or air-conditioning applications should never be used to evacuate
a system. Operating scroll compressors in deep vacuum could damage
internal motor parts and lead to unacceptable high temperatures in the
compressor housing.
For flammable refrigerant operation below atmospheric pressure, see section 3.5 "System
protection for operation below atmospheric pressure".
5.11 Shell temperature
During normal operation, the discharge gas as well as the compressor top shell and discharge line
can reach temperatures up to the maximum discharge gas temperature of 130/135 °C – see section
3.6 "Discharge gas temperature protection".
In a failure mode, the discharge gas temperatures can even get higher. Care must be taken to ensure
that wiring or other materials that could be damaged by these temperatures do not touch the shell.
5.12 Pumpdown cycle
WARNING
Vacuum operation! Creation of a flammable mixture! Fire hazard! During
operation below atmospheric pressure, a flammable mixture can form inside
the system. Ensure system tightness to prevent any ingress of air. For further
details see section 3.5 "System protection for operation below
atmospheric pressure".
CAUTION
Vacuum operation! Compressor damage! Compressor operation outside
the operating envelope is not allowed.
A pumpdown cycle to control refrigerant migration may have to be used for several reasons, for
example when the compressor is located outdoors without any housing so that cold air blowing over
the compressor makes the crankcase heater ineffective.
If a pumpdown cycle is used, a separate external check valve must be added. The scroll
discharge check valve is designed to stop extended reverse rotation and prevent high-pressure gas
from leaking rapidly into the low side after shut-off. The check valve might in some cases leak more
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AGL_HP_ST_ZHKCU_EN_Rev01
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