Pumped - Carel PRK300L3FK User Manual

control the CO condenser using the fans or the new EVS system:
2
Note: carefully check the pressure control settings; for general
uniformity of the software, automatic set point selection is not featured
for the diff erent types of control and diff erent types of refrigerant. For
example, the suggested default set point for the low temperature
compressors is 3.5 bars; in a cascade system (subcritical CO
natural refrigerant, the reference pressure values are around 11 bars.
Together with the set point, the probe limits and probe alarm thresholds
will be correctly confi gured.
•
Cascade, 2 suction lines, 2 condenser lines (external driver for managing
the heat exchanger on the second line), single board;
I/O
pR300
I/O
Fig. A.m
•
Cascade, 2 suction lines, 2 condenser lines (built-in driver for managing
the heat exchanger on the second line), single board;
I/O
pR300
I/O
Fig. A.n
) with R744
2
EEV
EVD
FBUS
evolution
Board with
pLAN address 1
I/O
EEV
Board with
pLAN address 1
I/O
•
Cascade, 2 suction lines, 2 condenser lines (built-in driver for managing
the heat exchanger on the second line), double board;
I/O
J1 5
J1 2 J1 3 J1 4
J11 pLAN
J10 4 3 2 1
J2 5 BMS2 J2 6 FBus2
pR300
FieldBus card B M S card
J4 J5
J1 J24 J2 J3
Board with
pLAN address 1
I/O
•
Cascade, 2 suction lines, 2 condenser lines (built-in driver for managing
the heat exchanger on the second line), double board;
I/O
Board with
pLAN address 1
J1 5
J1 2 J1 3 J1 4
J11 pLAN
J10
4 3 2 1
J2 5 BMS2 J2 6 FBus2
pR300
FieldBus card B M S card
J1 J24 J2 J3 J4 J5
I/O
A2.2 Pumped
Less used than traditional cascade subcritical systems, this solution
limits the use of HFC refrigerants to the equipment rooms. The medium
temperature units are supplied with pumped liquid CO
temperature units are fi tted with expansion valves. The CO
by a dedicated chiller (NH3 or r134a) inside a tank, normally with a tube
bundle evaporator. In addition to traditional systems, these also include
management of the pumps that deliver the liquid CO
temperature evaporators, where it does not expand but rather is only
superheated and returns to the receiver in a semi-liquid state.
89
EEV
EVD
FBUS
evolution
J1 5
J1 2 J1 3 J1 4
J11 pLAN
J10
4 3 2 1
pLAN
J2 5 BMS2 J2 6 FBus2
pR300
FieldBus card B M S card
J1 J24 J2 J3 J4 J5
I/O
Fig. A.o
EEV
pLAN
pR300
Board with
pLAN
I/O
address 2
Fig. A.p
, while the low
2
2
to the medium
2
Fig. A.q
pRack +0300025EN rel. 1.3 - 17.12.2015
ENG
Board
with
pLAN
address 2
is cooled