Stulz Cosmotec CVE Series, Use And Maintenance Manual

Page: 23 / 88

CVE-CVO
23
CONTROL AND SAFETY DEVICES
All equipment is checked and calibrated at the factory and normally
no further adjustments or interventions are required. If changes to
the automatism calibration become necessary for particular needs,
these must be carried out, with prior notice to STULZ SpA, only by
personnel specialised on the product. The air conditioner is
equipped with a series of command and control components that
ensure proper operation. The intervention of any of the safety
automatism is an indication of malfunction, and therefore it is
essential that the cause is removed. it is forbidden to make
electrical by-passes on safety equipment; this intervention not only
is hazardous but will also render the warranty null and void.
ELECTRONIC BOARD XCB, XCB Plus
The microprocessor-based electronic board is equipped with a set of
terminals which are necessary to connect the board to the
controlled devices (compressor, fans, …). Electronic board is housed
on internal side and can control only one unit.
MECHANICAL ADJUSTMENT THERMOSTAT (on models without
digital thermostat)
It is mechanical with gas load. The bulb is positioned at the sucked
air inlet of the cabinet and detects and controls the temperature by
sending the consent to the compressor. Limit operating range are
showed on technical label of air conditioner.
TEMPERATURE PROBE
Temperature probe is a NTC type, it is connected to analogic input
of electronic controller.
SAFETY SWITCH FOR HIGH PRESSURE
It stops the compressor operation when the internal pressure of the
circuit exceeds the calibration level.
DIFFERENTIAL PRESSURE SWITCH (if present)
This brings the condenser fan to a halt when the inside pressure is
lower than 8.5bar, this allow the air conditioner to work at a
minimum temperature of -20°C.
PRESSURE TRANSDUCER (if present)
The pressure transducer measures the condensing pressure and it is
connected to an analogic input of XCB Plus board. Value of
condensing pressure is used by XCB Plus board to adjust condenser
fan speed according to the external conditions.
CONTACTOR
Installed in models where the power or the components require its
presence; it controls the motors through operations of the auxiliary
circuit. They comply with IEC947-4-1 standards.
AUTOMATIC CIRCUIT BREAKERS (if present)
These protect against over-currents and short circuits. They have
adjustable thermo-magnetic tripping devices.
TRANSFORMER (if present)
In high power models it is used to transform from mains voltage to
auxiliaries voltage.
AUTOTRANSFORMER (if present)
It is present in models that they work with voltage bi-phase >230V
and three-phase. They are manufactured according to standard EN
61558-1, 2-13.
HEATER (if present)
It is used to heat internal air. It is controlled by XCB Plus board. The
heater is installed inside the unit, in front of supply internal air
opening.
MECHANICAL THERMOSTATS OF SAFETY OF THE HEATER (if
present)
They are of two types. The first is with automatic restart and it
protects the heater disconnecting the power supply in case of
excessive surface temperature of heater. Second mechanical
thermostat is with manual restart and it intervenes in case of fault
of evaporator fan.
PHASE SEQUENCE RELAY (if present)
The device trips when phase sequence is incorrect or when one of
the controller phases fails. With all phases detected and correct
phase sequence, the green “ON” LED is constantly switched on and
the output relay is energised. The green ON LED flashes and the
output relay de-energises when the phase sequence is not correct
and it block the cooling providing an alarm signal to controller.
STANDARD EQUIPMENT
Use and maintenance manual, conformity declaration, test report,
adhesive gasket, connector 9poles female for CE units (except
CVE03002200000), bag with screws/flat washer/threaded bolt/nuts,
cut-out.
7. CONTROL AND WORKING LOGIC
MECHANICAL THERMOSTAT
The thermostat has to be set within 25°C / +45°C. Regulation
has to be done with screwdriver, by skilled personal, acting on the
thermostat pin after switching off of the unit and remove panel of
air conditioner. Thermostat has an hysteresys of 4°C, therefore
compressor will start at a temperature about 4°C greater than set
point. After adjustment, close the panel of air conditioner previously
removed and switch on power supply.
ELECTRONIC THERMOSTAT
Description display/keypad
Air conditioners CVE (except CVE03) have display/keypad installed
on unit to display working conditions, state of unit and possible
alarms. It could be used to modify working parameters (for example,
il set point temperature). Units CVO display/keypad is provided
loose (as accessory if ordered). It has to be connected to connector
on back of air conditioner (upper terminal board) with cable. Here
below imagine about keypad.
Meaning of keys
( SET) Display or change set point. On programming
to choose parameter or confirm value
(
UP) In programmino to scroll parameters and to
increase value
(
DOWN ) In programming to scroll parameters and
to decrease value
(ON/OFF) Switch on and switch off device
Combination of keys
+
Block and unblock keypad
+ Enter on programming
+ Exit on programming