Lennox EMEA FRIGA-BOHN DUO CU 114, Installation Instructions Manual

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DUO CU
GB
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In the table below, you will find the abbreviations of the different types of pressure switches and an explanation
of their usefulness (note that the pressure switches HPS1 and HPS2 are not adjustable and must be replaced by
those provided in spare parts for operation in R134A, R450 and R513)
Designation Abbreviation Function Setting
General safety low pressure switch BPG
Shuts down all compressors via
common relay for all compressors
Its cut-off value must be
equal to the minimum
operating value of the
compressor
Compressor safety low pressure switch BPS
Shut off the compressor on which
it is connected
Its cut-off value must be
2°C higher than the
maximum operating
value of the compressor
Compressor safety high pressure switch HPS
Shut off the compressor on which
it is connected
Its cut-off value must be
2°C lower than the
maximum operating
value of the compressor
Regulated low pressure switch BPR
Regulates the operation of the
compressor on which it is
connected in emergency mode in
the case of an installation with PLC
(
Programmable Logic Controller)
or pressostatic operation
It must enable the
operation of the
compressor for the
nominal value of low
pressure
Regulated high pressure switch HPR
Regulates the operation of fan
condensers in emergency mode in
the case of an installation with PLC
or pressostatic operation
It must enable the
operation of the fan
condenser for the
nominal value of high
pressure
Low pressure frame switch BPE
Engages the rescue mode after a
delay during a malfunction of the
PLC (non-functioning of the
compressors)
Its threshold value must
be equal to the lowest
temperature produced
High pressure frame switch HPE
Engage the rescue mode
immediately when the PLC
malfunctions (non-functioning of
the condenser fans)
Its threshold value must
be equal to the
condensation set point
tempe 5 ° C