Diapositiva 1

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Unisplit UWA - MRA
Maggio 2007
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Unisplit UWA - MRA
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Unisplit UWA

• INTERNAL EVAPORATOR UNIT (UWA)
• The self-supporting steel panels are finished in
  epoxy powder and lined internally
• with abrasion-resistant self-extinguishing
  material for noise and heat insulation.
• EU2-efficiency air filter in self-extinguishing
  material rigid metal frame.
• Galvanised steel double-inlet centrifugal fan(s)
  with forward-curved blower keyed directly to
  motor shaft.
• Differential pressostat to activate alarm in the
  event of low airflow.
• Cooling coil with large frontal area consisting
  of copper tubes mechanically expanded into
• aluminium fins and complete with stainless steel
  tray.
• The electrical panel, housed in a compartment
  isolated from the airflow, conforms to Norm
• 73/23/CEE and includes
• auxiliary 24V transformer
• general switch
• magnetothermal protection

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Unisplit MRA
EXTERNAL CONDENSING UNIT (MRA) Structure
and external panels are entirely in painted
galvanised steel to guarantee corrosion
resistance. Paint conforms to ASTM B 17 norms,
which include testing for resistance to saline
mist. These units can be installed in even the
harshest of conditions. All external fastenings
are stainless steel and the closure of the
external housing is to IP44 protection standards.
Units have hermetic Scroll compressors with
high-energy efficiency and low noise levels, with
built-in thermal protection. Standard
configuration ecological refrigerant R407C High
and low pressure pressostats Fans are of the
axial type, statically and dynamically balanced
on two planes, with blower in non-oxidising
material. The external rotor motor can be fitted
with speed regulation. Fans are mounted on a
metal support grille, which conforms to safety
legislation. Modulation of condenser fan speed
is stepless. The electrical panel, housed in a
compartment isolated from the airflow, conforms
to Norm 73/23/CEE and includes general switch
magnetothermal protection remote control switch
Both internal and external unit have their own
power supply
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Technical data
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General Description
The UNISPLIT is an air-cooled direct-expansion
air conditioning unit. UNISPLIT air conditioner
consists of two distinct elements the
evaporating section (UA/UF) installed in the
air conditioned room and the condensing section
(MRA) installed outside. The evaporating
section is designed either for ceiling or for
wall installation and enables the control of room
parameters via a sophisticated microprocessor
control.
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Start Up and Testing
EVACUATION OF THE REFRIGERANT CIRCUIT The unit
is pre-charged with a minimum refrigerant load
which is not sufficient to enable the unit to
function. Create a vacuum in the connection lines
and in the MRA remote condenser maintain a
pressure of less than 100 absolute Pa
(recommended pressure 0,3 mbar or 0.25 mmHg ca)
to evacuate the air and remove any traces of
humidity. Allow at least two hours to create the
vacuum and maintain it for at least one hour. Do
not use the compressor to create the vacuum in
the circuit. Fill the circuit with HCFC-R22
refrigerant until the line pressure is
stabilised. START-UP PROCEDURE 1. Check the
auxiliary circuit transformer primary to ensure
that the connection terminal corresponds to the
effective power supply voltage. 2. Turn on the
power supply to the electrical panel, close the
switch on the unit, turn on the power supply to
the unit and check that the yellow LINE LED on
the control is on. 3. Arm all the automatic
switches on the electrical panel 4. Open all the
shut-off valves on the refrigerant circuit 5.
Press the ON/OFF button on the control to start
the unit. After a short delay the fan will start
and the green SYSTEM ON" LED will come on on the
user terminal If there is an alarm condition,
signalled by the red ALARM LED and by the
buzzer on the user terminal, consult the
instruction manual for the microprocessor control.
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Start Up and Testing
REFRIGERANT LOAD After starting the compressor
slowly charge the UC internal unit with
refrigerant via the special valve located
immediately after the thermostatic valve, until
the bubbles in the flow sight glass disappear.
Check the data plates of the unit and of the
compressor for the type of refrigerant used. The
charging must be done under the projects room
conditions and with a discharge pressure of 16-18
bar (equivalent to a saturation temperature of
48C). If the unit has on-off condensation
control, make sure that the condenser fan does
not keep switching on and off, if necessary by
partially obstructing the intake area. Check that
the supercooling of the liquid at the
thermostatic valve intake is between 3 and 5C
less than the condensation temperature reading on
the manometer scale and that the superheating of
the vapour at the evaporator output is between 5
and 8C. The dilution ratio of the system is
around 5 by weight of oil to refrigerant. In the
event that it is necessary to top up the oil use
only these types
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Start Up and Testing
REGULATION OF CONDENSATION PRESSURE Condensation
pressure of the unit must be between a minimum
of 40C (for correct function of the thermostatic
valve and to avoid the freezing of the evaporator
coil with low temperatures) a maximum of
63C. The unit has condensation pressure
regulation devices which are set as described
below.
SETTING THE REGULATION AND SAFETY DEVICES After
starting the unit, make the following
settings Ref. Description Action Diff.
Re-set AP HP Pressostat 25.5 bar (opening) -
manual BP LP Pressostat 2.0 bar (opening) 1.5 bar
3.5 bar TSR Electric heater safety thermostat
320C (opening) manual The UWA/UWF internal
unit is fitted with an airflow pressostat (FS).
This detects potentially dangerous situations
resulting from function of the electric re-heat
(on UC 0341 T models) if the fan is faulty or
the filter is blocked. If there is little or no
airflow the temperature inside the unit could
reach very high levels. Further protection is
provided by the heating element safety thermostat
(TSR) and the emergency function relay (RFE)
which cuts power supply to the heating element
and activates free-cooling function if the power
to the external MRA unit fails
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Start Up and Testing
SETTING THE DIRTY FILTER SENSOR The optional
dirty filter pressostat (PFS) must be set as a
function of the pressure drop. This depends not
only on how dirty the filter is but also on the
airflow and therefore on the setting of the speed
regulation. The setting must be made when the
filter is clean and in the following sequence -
Set the speed regulator at the desired function
value (see FAN SPEED REGULATION) - Set the
pressostat intervention point at 1.5 mbar -
Gradually cover the filter check that the
pressostat intervenes with around 50-60 of the
surface covered If the pressostat does not
intervene, gradually reduce its setting if it
cuts in too soon, raise the setting..
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Basic instructions
WHAT TO DO IF THE UNIT DOES NOT START Check
that 1. the electrical panel and the auxiliary
circuit transformer primary are powered 2. the
general switch and the automatic switches on the
electrical panel are closed 3. the fuse on the
auxiliary 24V circuit is not blown 4. the
connectors on the control circuit are correctly
inserted 5. the yellow LED on the control circuit
is on 6. there are no alarm conditions signalled
by the user terminal with the buzzer or the red
LED 7. the external unit has power supply and
that RPT terminals 20 and 240 are powered.
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Basic instructions
WHAT TO DO IF THE UNIT DOES NOT PROVIDE ENOUGH
COOLING If, 30 minutes after starting up the
unit, the room temperature is too high, check
that 1. the electrical panel has power
supply 2. The automatic switches on the
electrical panel are all armed 3. The control is
not signalling an alarm condition (see also the
instruction manual for the control) 4. the
temperature set value is correct and that the
compressor is working 5. the airflow is not
obstructed (see section on Air Distribution) 6.
The thermal load to be dissipated is not greater
than planned 7. the external unit has power
supply IMPORTANT in the event of a fault with
the unit, call only qualified technicians for
service
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Basic instructions
REGULAR MAINTENANCE Check that the room
parameter values shown by the control are
correct Check the filters regularly for dirt
and obstructions and replace them in the event of
a dirty filter alarm Check the refrigerant
charge, ensuring that there are very few or no
bubbles visible in the flow sight glass on the
refrigerant circuit Check that the noise made
by the unit is normal Check the correct flow of
condensation water to the drain Remove all
foreign bodies (leaves, seeds, dust, etc.) from
the external condensing unit using a jet of
compressed air or water.
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Basic instructions
POSITIONING THE EXTERNAL MRA UNIT This unit is
designed to be installed outdoors but should be
protected from rain, snow and water flowing from
drains or gutters. Do not install the unit near
the sea (it should be at least 200m from the
shore) or in areas with sulphurous springs. Make
sure that the unit is not exposed to air
containing inflammable or greasy substances. The
airflow taken in by the fans via the condenser
coil must not be obstructed in order not to
reduce efficiency or cause the compressor safety
devices to stop the unit. The minimum distances
in fig.5 must be respected. The air discharge
side (the fan side) must never be directed
towards a wall. If the installation location is
windy, the unit should be installed in a
sheltered position the wind could obstruct the
airflow through the cooling coil or make it
excessive. If this is not possible, adequate
wind-protection measures should be taken (see
fig. 6). Check that the load capacity of the
surface under the unit is sufficient to support
its weight (see dimension diagram).
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Refrigeration Diagram
Reference Description AP High pressure
pressostat BP Low pressure pressostat C Compress
or CA Condenser EV Evaporator FD Filter
Drier SF Liquid indicator VT Thermostatic
valve RCC Crankcase heater RVC Condenser Fan
Speed Regulator
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Overall dimensions / connections
U
I
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Overall dimensions / connections
Model Supply voltage 230/1N/50 Power supply
voltage 2x2.52.5PE Electrical usere Nominal
power Electrical reheating 3 kW Fans 0.44
kW S Cond. Discharge 21 I Refrigerant
inlet 10 (3/8) U Refrigerant outlet 16 (5/8)
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External Internal link
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Electrical panel lay-out UWA
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Electrical panel lay-out MRA
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Alternating Relay
Alternating relay for 2 or 3 units Output 5
A SPST relay For mounting on DIN-rail in
accordance DIN/EN 50 022 35.5 mm DIN-rail
housing LED indication for relays and power
supply Galvanically separated power supply
Built-in delay for the second or third
simultaneous activation is required
It is a relay made to alternate 2 or 3 pumps in a
multiple pump system. In case of need (i.e.
overflow) the second, or even the third pump can
be activated together with the first one. In case
more than one pump is required to start at the
same time, the pumps start 10 s after the
previous to avoid big inrush current. The LED's
indicate the state of the alarm and the output
relay. 35.5 mm wide housing suitable both for
back and front panel mounting.
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Alternating Relay
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Installation considerations
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Installation considerations
To ensure proper refrigerant flow and oil return,
the condenser should be installed in a level
position. All condensers have mounting holes for
securing them to steel supports above load
bearing walls helps to minimise sound and
vibration transmissions. A concrete pad is
adequate support for ground installations.

• Installing the pipework
• Note Do not open the shut off valves on the
  hot gas and liquid lines until all pipe
  connections are made
• and you are ready to vacuum the entire system .
• This will prevent the filter dryer and the
  compressor oil from becoming contaminated with
  moisture.
• 1. Install the piping, taking note of the
  following
• Welding
• All joints must be braze-welded
• Avoid butt welds by using sleeves on enlarging
  one of the pipes using a pipe opener
• Use silver-based solders
• Ensure the weld is properly made ,a faulty weld
  which leads to are refrigerant leak later on ,can
  seriously damage unit.
• Always use large-radius bends (bending radius at
  least equal to the pipe diameter). Bend the pipes
  as follows
• 2. Connect the pipes to the condenser
• Condensers with butt-welded pipe connections cut
  the pipe on the condenser ,enlarge it and weld it
  to the pipeline
• 3. Once all the external pipingis complete and
  before the pipes are connected to the indoor unit
  clean out the pipelines as follows
• Plug the fre ends of the pipes
• Connect a dry nitrogen cylinder, fitted with
  reducer (max pressure 10 bar), to the1/4 SAE
  Schrader valve of the condenser.

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Installation considerations

• Note For dual circuit units repeat for each
  circuit.
• 1. Open all shut-off valves in the refrigerant
  system, both in the indoor unit and on the
  condenser (if fitted)
• 2. Connect an high efficiency vacuum pump
  (suitable for use with polyester oils) to the
• Compressor suction and discharge ports via the
  ¼ SAE fittings on the rotalock (if fitted),
  ensure the rotalock are open.
• If rotalock are not fitted to the unit, connect
  the pump to the Schrader valves on the compressor
  suction and
• discharge lines
• The ¼ SAE fitting on the rotalock of the liquid
  receiver ensure the rotalock is open.
• 3. Connect the refrigerant cylinder to the
  Schrader valve between the expansion valve and
  evaporator .
• 4. Pull an initial vacuum to a residual pressure
  of 0,03 mbar (absolute).
• leave the unit stand for 3 hour and then check if
  the vacuum exceed 1,3 mbar absolute.
• If it is ,there is still too much moisture in the
  system or there is a leak, continue to vacuum the
  unit.
• If the vacuum does not exceed 1.3 mbar absolute
  after 3 hours ,the humidity content of the
• system is less than 50ppm. The pressure must be
  measured by means of a vacuum gauge normally
• fixed on the pump. If there is still too much
  moisture in the system or there is a leak in a
  system,
• repair the leak as indicated instep 6.

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REFRIGERANT CHARGE (R22 R407C) Note For dual
circuit units repeat for each circuit.
Pre-charge the unit as described
earlier Connect the refrigerant cylinder to the
schrader valve between the expansion and
evaporator . Start the unit as described in the
start-up section of this manual Start the
compressor manually , ensure the unit is not in
dehumidification mode , (adjust the humidity
setpoint, refer to the relevant controller manual
if necessary) Ensure a costant condensing
temperature if necessary , partially obstruct
the condenser coil surface to obtain these
conditions. Charge the unit until the bubbles in
the sight glass have disappeared and the
refrigeration circuit works as normal. Please
check the sight glass after 10 minutes (the
minimum time in order to permit the verify also
the subcooling that give the indication of the
correct refrigerant charge The subcooling is
the difference between the condensing temperature
corresponding to the relative pressure read by
Manometer (High pressure) and the real
temperature read by the thermometer positioned on
the condenser outlet (we suggest to take a note
of the measure before the thermostatic valve. The
difference between the 2 value must be 5/10C
. If the subcooling is too higher it means that
the unit is too charge , and if is less it means
that the unit is discharge.
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R407C Note For dual circuit units repeat for
each circuit.
Open all shut-off valves in the refrigerant
system, both in the indoor unit and on the
condenser (if fitted) Connect an high efficiency
vacuum pump (suitable for use with polyester
oils) to the Compressor suction and discharge
ports via the ¼ SAE fittings on the rotalock (if
fitted), ensure the rotalock are open. If
rotalock are not fitted to the unit, connect the
pump to the Schrader valves on the compressor
suction and discharge lines. 3. Connect the
refrigerant cylinder to the Schrader valve
between the expansion valve and evaporator . 4.
Pull an initial vacuum to a residual pressure of
0,03 mbar (absolute). leave the unit stand for 3
hour and then check if the vacuum exceed 1,3
mbar absolute. If it is ,there is still too
much moisture in the system or there is a leak,
continue to vacuum the unit. If the vacuum does
not exceed 1.3 mbar absolute after 3 hours ,the
humidity content of the system is less than
50ppm. The pressure must be measured by means
of a vacuum gauge normally fixed on the pump. if
there is still too much moisture in the system
or there is a leak in a system. repair the leak
as indicated instep 6. Break the vacuum as
follow Close the valve of the vacuum pump Open
the valve of the refrigerant cylinder until the
system reaches a pressure of approx.3 bar .
Ensure that the cylinder delivers only liquid
refrigerant. Pre-charging is now complete. The
vacuum pump and the refrigerant cylinder can now
be disconnected as follow 6. Inspect all
connections/joints using a leak detector. If leak
is found ,reclaim the charge , repair the leak
and repeat step 3 to 6. Never use the
compressor to create a vacuum (this invalidates
its guarantee)
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CREATING A VACUUM
IN THE SYSTEM FOR EVACUATION AND CHARGING OF
R407C REFRIGERANT Connect the vacuum pump to
the valves in the compressor housing placed next
to the high pressure switch and downstream the
thermostatic valve. The vacuum pressure created
must be taken to 5-6 Pascal. Connect the R407C
refrigerant supply can to the Schrader valve
fitted downstream the thermostatic valve. The
charging must be done under normal conditions,
(in the case of a heat pump the charging must be
done with the unit set in refrigerant function).
Connect the valves to the the Schrader valve
placed next to the high ands low pressure
pressostat, open the refrigerant supply can and
let the refrigerant flow in, turn on the
compressor and check the flow sight glass,
continue to charge the refrigerant fluid until
there are no bubbles in the sight flow
glass. Running pressure must be more or less 4,5
bar for INTAKE (low pressure) and 18 bar in
DISCHARGE (high pressure) with unit under normal
running conditions and an external temperature of
20-25 . In order to complete the charge check
the SUPERHEATING, that must be between 4 -6C.,
and the SUBCOOLING that must be between 3 -5C
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SUPERHEATING SUBCOOLING
SUPERHEATING It is verified by checking the
difference between the temperature reading of the
thermometer placed near the LOW PRESSURE
PRESSOSTAT and the temperature of the R407C
MANOMETER that refers to the temperature T DEW.
Point (C) ( superheating guarantees that the
compressor does not receive liquid) If there
is. Great difference between the two
temperatures Check that the flow sight glass
does not have bubbles, check the subcooling ,
eventually check the setting of the thermostatic
valve. Slight difference between the two
temperatures Slightly turn the thermostatic
valve, wait 10-15 minutes and the check the
reading again. SUBCOOLING liquid subcooling
is verified using the temperature difference
between the thermostatic reading, using a
contact thermometer placed next to the SIGHT FLOW
GLASS and the condensation temperature of the
R407C MANOMETER SCALE T BUBBLE Point (C). The
difference between the two Temperatures must be
about 3-5.the subcooling guarantees correct
functioning of the thermostatic valve, that must
be feed by the liquid. If IF THE ABOVE
MENTIONED TEMPERATURE IS LESS THAN 3-5 the
unit has not been sufficiently charged. IF THE
ABOVE MENTIONED TEMPERATURE IS GREATER THAN 3-5
the system might be overcharged.
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SUPERHEATING SUBCOOLING
IMPORTANT it is important to double check the
SUBCOOLING and the SUPERHEATING EXAMPLE A
Subcooling 6C Superheating
8-9C Flow sight glass Set the thermostatic
valve by opening it slightly - wait about 15
minutes , then check again the reading, if the
subcooling is still 5-6 higher and the
superheating has dropped to 4C and the flow
sight glass is completely free of bubbles, then
the refrigerant liquid will have to be slightly
discharged IMPORTANT THE REFRIGERANT LIQUID
MUST BE DISCHARGED UNDER NORMAL CONDITIONS
(LIQUID STATE). EXAMPLE B Subcooling 3C
Superheating 2-3C
Flow sight glass with bubbles Slightly
close the thermostatic valve until the
Superheating reaches 4-5C. If the subcooling
remains low and the flow slight glass presents
bubbles, top up by adding more refrigerant liquid
to the unit and check the reading again, until
the unit is completely charged In the case that
gases enter the circuit the Subcooling will be
very high 8-10C and the flow slight glass will
present bubbles, a low or/and modulating
evaporation and a very high compressor discharge
temperature ( 40-50C more than the Condensing
temperature read on the manometer Scale).
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THE SUPERHEATING

• SUPER HEATING
• The super heating is verified by the pressure
  gauges connection
• to the low pressure shrader and by the reading
  of a connection
• thermometer placed on the suction pipe-line(inlet
  of the
• compressor, in this case)
• The super heating must reach about 7-8
• Working operations
• To read the value of the gauges pressure.
• To turn this pressure into temperature by a slide
  rule or the
• saturation curve (see the schedule)
• To read the thermometer indication.
• THE SUPER HEATING IS EQUAL TO THE DIFFERENCE
  BETWEEN THE
• TEMPERATURE READ BY THE THERMOMETER AND

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CHECK OF THE COOLING CHARGE IN THE REFRIGERATING
CIRCUIT.

• SUB COOLING
• The subcooling is verified by the gauges
  connection to the high pressure shrader and by
  the reading of a
• connection thermometer placed on the liquids
  pipe-line.(in the pipe that joins the liquid
  indicator to the thermostatic)
• The subcooling has to be around 3
• Operations
• To read the pessure gauges value
• To turn this pressure into temperature by a slide
  rule or the saturation curve( see the schedule)
• To read the thermometer indication
• THE SUBCOOLING IS EQUAL TO THE DIFFERENCE BETWEEN
  THE TEMPERATURE READ
• BY THE THERMOMETER AND THE ONE FOLLOWING BY THE
  PRESSURE CONVERTION.