AGL_Stream_ST_A2L_A1_4M_6M_EN_Rev00 13
3.2.2 Low-pressure protection
3.2.2.1 Applications with A1 refrigerants
CAUTION
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.
CAUTION
Low suction pressure operation! Compressor damage! Do not operate
with a restricted suction. Do not operate with the low-pressure limiter bridged.
Do not operate compressor at pressures that are not allowed by the operating
envelope. Allowing the suction pressure to drop below the envelope limit for
more than a few seconds may overheat the pistons and cause damage to
parts.
Applicable regulations and standards shall be followed to apply appropriate control and ensure that
the pressure is always above the required minimum limit.
The low-pressure control must be installed correctly into the suction line, which means that no service
valve is allowed between the compressor and the pressure protection.
The minimum cut-out setting shall be determined according to the refrigerant and the allowed
operation envelope – see Select software at www.climate.emerson.com/en-gb.
The low-pressure cut-out should have a manual reset feature for the highest level of system
protection.
3.2.2.2 Applications with A2L refrigerants
WARNING
Operation below atmospheric pressure! Fire hazard! During operation
below atmospheric pressure, a flammable mixture can form inside the system.
Make sure that air does not enter the system.
CAUTION
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.
CAUTION
Low suction pressure operation! Compressor damage! Do not operate
with a restricted suction. Do not operate with the low-pressure limiter bridged.
Do not operate compressor at pressures that are not allowed by the operating
envelope. Allowing the suction pressure to drop below the envelope limit for
more than a few seconds may overheat the pistons and cause damage to
parts.
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.
Emerson requires without exception that all 4M* and 6M* compressors in A2L systems be fitted with
a low-pressure control, with no service valve between the low pressure side and the pressure control.
3.2.3 Maximum allowable pressures
The maximum allowable pressures according to EN 12693 shown on the compressor nameplate are
obligatory and must not be exceeded.
▪ High-pressure side (HP): 28.0 bar (g) (up to S/N 14K46143M)
32.5 bar (g) (from S/N 14K46144M onwards)
▪ Low-pressure side (LP): 22.5 bar
NOTE: The compressor operating range may be restricted for various reasons. Check the
application range limitations in Select software at www.climate.emerson.com/en-gb.
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