3
2 DESCRIZIONE E SCELTA DELL'UNITÀ
The devices of the NRA range are
units used to produce cold water for
technological systems; the heat pump
models also allow you to produce hot
water for heating. They consist of two
R407C refrigerating circuits and a
single hydraulic circuit (which may or
may not be fitted with an accumulation
unit).
The presence of more than one scroll
type compressor allows the NRA chillers
various capacity controls of the cooling
capacity.
The use of more than one scroll type
compressor allows a high level of
efficiency, even with partial loads. In
these cases in fact, a variable number
of scroll compressors are working,
each at 100% (i.e. maximum efficiency)
of the output power. By means of
a microprocessor, the electronic
regulation controls and manages
all the components and working
parameters of the unit; an internal
memory registers the working
conditions in the moment when an
alarm condition arises, in order to
visualise it on the display. The units
have a protection rating of IP 24.
2.1 MODELS AVAILABLE
- “STANDARD COOLING ONLY (°)”
maximum outside temperature
allowed 42°C. Acoustic protection
cover for the compressor, for quiet
operation.
- “HEAT PUMP (H)” in cooling mode
the operating limits arrive to a
maximum outside air temperature
of 46°C. NRAH do not envisage the
following configurations:
- YH (with processed water lower
than 4°C)
- HC (condensing heat pump)
- HA (heat pump in high
temperature because the heat
pump is, by its very nature, a
machine for high temperatures)
2.2 VERSIONS AVAILABLE
- "STANDARD/BASE"
Maximum outside temperature
allowed 42°C, acoustic cover for the
compressor, for quieter operation.
- "HIGH TEMPERATURE" (available
only for cold working versions)
via the expansion of the pack finned
heat exchanger, it allows you to
widen the operating limits, arriving at
a maximum outside air temperature
of 46°C.
- “SILENCED (L)” r e pr e s ents the
models designed for particularly
quiet operation. All the sizes
are fitted with a device for
regulating the fan speed. When
the temperature is lower than
35°C, the low noise version
further reduces the number of fan
rotations, thereby obtaining an
even quieter operation than that in
nominal conditions.
- “SILENCED HEAT PUMPS (HL)”
represents the models designed for
particularly quiet operation.
All the sizes are fitted with a device
for regulating the fan speed.
- “HEAT RECOVERY”
A unit with air condensation, complete
with section for partial heat recovery.
The heat exchanger is specially scaled
to guarantee heat recovery for the
production of hot water for use in
bathrooms or other purposes.
1. Desuperheater (D)
The desuperheater is also available for
heat pump versions, limitedly in the coo-
ling function. It must be intercepted in
the heating function.
2. Total heat recovery (T)
In heat pumps total recovery is only
available for the “OO versions without
hydronic kit”
- “CONDENSING UNITS C”
-
“SILENCED CONDENSING UNITS
LC”
- “VERSION Y” is the version that allows
you to produce chilled water below
the standard value of +4°C, to a
minimum of -6°C.
For lower values, contact the
company headquarters.
ONLY THE VERSION YA IS
AVAILABLE.
WARNING
Forthedevicesdesigned to work with a
low air temperature, and also the heat
pumps, before starting up the unit (or
at the end of each period of prolonged
disuse) it is extremely important for
the oil of the compressor carter to
be heated beforehand, via the power
supply to the special heaters, for at
least 8 hours.
The carter heater is automatically
powered when the unit stops, provided
that the unit is kept under tension.
ALL THE VERSIONS COME WITH:
1. Evaporator anti-freeze heater
2. Compressor carter heater
3. Remote control panel
4. Water filter (supplied with the ver-
sions without accumulation)
5. Flow switch only in the versions with
accumulation
HEAT PUMPS
TP1 Trasduttore di bassa pressione
TP2 Trasduttore di alta pressione
DCPX Dispositivo di regolazione della ve-
locità dei ventilatori di serie per la
sola versione HL
CHILLERS WITH ACCUMULATION
1. Evaporator anti-freeze heater
2. High or low pressure pumping unit
3. OPTION:
There is also the possibility
to have a reserve pump.
The stand-by pump that in NRA 800
- 900 - 1000 models is controlled by
the electronic card which enables
the alternate operation of the two
pumps to optimize the working time.
A switch on the NRA 1250 - 1400
- 1500 - 1650 - 1800 electric panel
enables the pumps to be manually
switched over.
4. For the heat pump versions, an
accumulation (pre-set for the
insertion of integrative heaters) is
available upon request.
CHILLERS WITH DESUPERHEATER
DCPX Standard
2.2.1 Standard equipment
