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AGL_HP_ST_YHK1E_E_Rev02
3.4
Pressure safety controls
3.4.1 High-pressure protection
Applicable regulations and standards, for example EN 378-2, shall be followed to apply appropriate
control and ensure that the pressure never exceeds the maximum pressure limit.
High-pressure protection is required to stop the compressor operating outside the allowable pressure
limit. The high-pressure control must be installed correctly, meaning no service valve between the
compressor and the pressure protection is allowed.
The high-pressure cut-out setting shall be determined according to the applicable standard, the type
of system, the refrigerant type and the maximum allowable pressure PS.
3.4.2 Low-pressure protection
WARNING
Operation below ambient pressure! Fire hazard!
During operation below
ambient pressure, a flammable mixture can form inside the system. Make sure
that air does not enter the system.
IMPORTANT
Operation outside the application envelope! Compressor breakdown!
A
low-pressure protection shall be fitted in the suction line to stop the
compressor when it operates outside the envelope limits.
Make sure that the pressure never falls below atmospheric pressure. If it does, immediately de-
energize the power supply of the compressor and check the cause of the low pressure before
restarting the compressor.
To prevent the pressure from falling below atmospheric pressure, Emerson requires that YH*K1E
compressors be fitted with a low-pressure control, with no service valve between the low-pressure
side and the pressure control.
For hermetically sealed system, in case the approved application envelope is below atmospheric
pressure, the following rules shall be observed:
▪
valid only for hermetically sealed systems
– see safety standards for definition;
▪
the minimum absolute pressure is 0.5 bar;
▪
a discharge temperature control is mandatory to stop the compressor when exceeding the
maximum discharge temperature
– see
Chapter 3.6 "Discharge gas temperature protection"
.
3.5
Crankcase heater
WARNING
Ignition source in a potentially flammable atmosphere! Fire hazard!
The
crankcase heater is not an ignition source during normal operation but could
become one when not installed properly according to installation instructions.
Ensure correct electrical and mechanical installation.
CAUTION
Overheating and burnout! Compressor damage!
Never apply power to the
crankcase heater in free air, before the crankcase heater is installed on the
compressor or when it is not in complete contact with the compressor shell.
IMPORTANT
Oil dilution! Bearing malfunction!
Turn the crankcase heater on 12 hours
before starting the compressor.
A crankcase heater is used to prevent refrigerant migrating into the shell during standstill periods.
The installation of a crankcase heater is required when the system charge exceeds the charge limits
indicated in
Table 7
.
This requirement is independent from system type and configuration.
Summary of Contents for Copeland Scroll YH16K1E
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