Cooling Circuit; Frame; Safety And Control Components; Electrical Components - AERMEC WSA Serie Manual Técnico De Instalación Y Mantenimiento

5. 1

COOLING CIRCUIT

Compressors
Semi hermetic high-efficiency screw
compressors, with a cooling capacity
regulation by means of continuous
modulation from 40 to 100% (from 25
to 100% with electronic valve) and fit-
ted with:
- Thermal motor protection
- Oil discharge temperature check
- Electric heater for the heating of the oil
casing with the compressor at a stand-
still
- Reset button.
Exchanger (condenser)
Of the plate type (AISI 316), it is insula-
ted externally with closed cell material
to reduce thermal dispersions.
Exchanger (evaporator)
Of the plate type (AISI 316), it is insulated
externally with closed cell material to
reduce thermal dispersions.
Liquid separator
(only E condenserless versions)
Placed in the intake to the compressor
as protection from any returns of coo-
lant, flooded starts, functioning with
liquid present.
Filter drier
Of the mechanical type made of cera-
mics and hygroscopic material able to
trap impurities and any traces of humi-
dity in the cooling circuit.
Sight glass
For checking that the refrigerant gas
load and any humidity in the cooling
circuit.
Thermostatic valve
The mechanical type valve with outside
equaliser on the evaporator outlet mo-
dulates the gas flow to the evaporator
depending on the thermal load in such
a way as to ensure the proper degree
of overheating to the intake gas.
Liquid and pressing taps
They allow the refrigerant to be cut off
during extraordinary maintenance.
Solenoid valve
The valve closes when the compressor
turns off, preventing the flow of refrige-
rant gas towards the evaporator.
One way valve
This allows the refrigerant to flow in
just one direction.
8
Mechanical filter
Positioned in the liquid injection line
to the compressor, it retains the impu-
rities that may be present in the refri-
gerant circuit.
CPCE
(only in the models with total or par-
tial heat recovery)
This allows changing condensa-
tion into an adequate heat recovery
exchanger for hot water production.
5.2

FRAME

Load-bearing structure
Made of hot galvanised steel sheet of
adequate thickness, it is painted with
polyester powders able to resist the
atmospheric agents over time. Colour
RAL 9002
Acoustic protection cover
(silenced versions)
IT is made of hot galvanised steel sheet
of adequate thickness, with internal
acoustic insulation, and externally
painted with polyester powders able
to resist the atmospheric agents over
time. Colour RAL 9002.
5.3 SAFETY AND CONTROL
COMPONENTS
High pressure switch
(manual + tool)
Factory-calibrated, it is placed on the
high pressure side of the cooling cir-
cuit, it shuts down compressor opera-
tion in the case of abnormal operating
pressure.
Low pressure transducer.
It makes it possible to show the value
of the compressor's intake pressure
(one per circuit) on the microprocessor
card display. Placed on the low pres-
sure side of the cooling circuit, it shuts
down compressor operation in the case
of abnormal operating pressure.
High pressure transducer
It makes it possible to show the value
of the compressor's delivery pressure
(one per circuit) on the microprocessor
card display. Placed on the high pres-
sure side of the cooling circuit, it shuts
down compressor operation in the case
of abnormal operating pressure.
Cooling circuit safety valves (HP - LP)
Calibrated to 22 bar HP and 16.5 LP,
they cut in relieving the overpressure
in the case of abnormal operating pres-
sures.
5.4

ELECTRICAL COMPONENTS

Electrical panel
Contains the power section and the
management of the controls and safety
devices. This conforms with standard
CEI 60204-1, and with the electroma-
gnetic compatibility Directives EMC
89/336/EEC and 92/31/EEC.
NOTE
Furthermore, all the cables are wired
for immediate recognition of all the
electrical components.
Door lock knife switch
THE electrical panel can only be acces-
sed by cutting off power using the
opening lever on the panel itself. This
lever can be locked in place using one
or more padlocks, during maintenance
in order to prevent the machine being
powered up accidentally.
Control keypad
Provides full control functions.
For a detailed description of the keypad
refer to the user manual.
- compressors thermomagnetic switch.
- secondary thermomagnetic switch pro-
tection
5.5

ELECTRONIC REGULATION

Electronic regulation on the "WSA" chil-
lers consists of control cards for each
compressor connected to each other in
a network and a control panel with di-
splay. In the case of models with more
compressors, the card that controls
compressor 1 is the "MASTER" card,
while the others are "SLAVE". On each
card, the transducers, loads and alarms
corresponding to the compressor that
commands are connected, while the
general machine ones are connected
only on the "MASTER card.
Microprocessor
- Remot e on/of f wit h ext ernal
contact without power
- Multilingual menu
- Phase sequence control
- Independent control of individual
compressors
- Ammeter transformer
- Cumulative failure block signalling
- Alarm log function
- Daily/weekly programming
- Inlet/outlet water temperature
display
- Alarm display
- Full proportional regulation of the
output water temperature