Read Sharp GU-XC157 Service Manual online
ambient temperature 35 °C; high speed;
ambient temp 7 °C D.B., 6 °C W.B.; high speed.
2 - Electronic control
3 - Fan section
4 - Receiver
5 - Heat exchanger
6 - Air filter
8 - Protection grill
9 - Reverse cycle valve
11 - Reactor
ceiling or vertical free-standing installation, connected to a
compact outdoor unit by means of refrigerant lines.
Conditioners are equipped with an adjustable speed rotary
compressor with inverter, and are controlled by a sophisticated
The power-supply frequency adjustment function of the inverter
allows variation of the speed of the electric motor driving the
compressor. The implementation of this technological feature to
split system units permits automatic adjustment of compressor
speed, and therefore of the performance of conditioners during
heavy-duty operating conditions (daily or seasonal external
temperature peaks, temporary indoor loads) as well as during less
demanding periods (nocturnal or mid-season operation).
This feature also allows the unit to reach the set temperature
rapidly, then to maintain it while operating at lower power. Not only
are ambient temperature fluctuations reduced and comfort
conditions enhanced, but significant energy savings are made
thanks to the greater efficiency of the refrigerant system when
operating with partial loads, and the lower number of compressor
cut-ins and cut-outs.
Both the indoor and the outdoor unit are extremely silent and
characterised by their high standards of efficiency and reliability,
also thanks to the refined adjustment system which prevents
operating faults to ensure the safest of working conditions.
The microprocessor control offers a range of operating programs,
and uses sophisticated “Fuzzy” and proportional-integral control
All conditioner functions are selected by means of an infrared-ray
remote control handset with liquid crystal display; in the event of
emergency, the system can be controlled by the push-button panel
on the indoor unit.
– heating (heat pump models only);
– ventilation only.
During the “automatic” function, the microprocessor adjusts the
rotary compressor and fan speeds according to information
received from internal and external sensors, independently
selecting the most appropriate operation parameters.
The “Full Power” function is designed for reaching the required
ambient temperature in the shortest possible time. Maximum output
is thereby achieved by the unit, and remains active for an hour after
settings have been made.
During all operation programs (except for “automatic” and “Full
Power”), the user can select the internal fan speed. The remote
control handset can regulate the horizontal grille directing
conditioned air flow into the room.
For a more detailed description of unit functions, see the user
The unit houses the following components:
– heat-exchange coil with aluminium fins;
– compact and silent 4-speed centrifugal fan section;
– electrical enclosure housing the microprocessor board;
– temperature probes for complete control of unit operation;
– reusable air filter, easy to remove for cleaning;
– horizontal drive-type grille with manually adjustable vertical slats
– remote control signal receiver;
– operating (red) and timer (yellow) indicator LEDs.
The unit is supplied complete with mounting brackets for vertical or
horizontal installation, and remote control handset with batteries.
– function type:
– internal fan speed control;
– ambient temperature control;
– conditioner ON/OFF control;
– drive-type air flow grille control.
The liquid crystal display shows all operation parameter settings,
thereby facilitating all programming operations.
The remote control handset is powered by two 1.5 V penlight
batteries, and can be used up to 7 m from the conditioner unit.
with polyurethane powder paint finish, and partly in plastic for
durability and resistance to rust.
The outdoor unit houses:
– soundproofed adjustable speed hermetic rotary compressor;
– heat-exchange coil with grooved copper tube and corrugated
– inverter electronic adjustment components;
– electrical enclosure with terminals for connection to power
The remote control handset is packed in the fan compartment of the
compressor speed necessary to satisfy the requirements of the
room treated, while maintaining optimal comfort conditions and high
refrigerant cycle efficiency. Conditioner power output is therefore
determined by the required ambient conditions and falls within the
field of power output ratings available.
The automatic adjustment stages of the unit will now be described.
When the unit is switched on, the microprocessor uses proportional
logic criteria to select the most suitable frequency to be supplied to
the compressor, according to the difference between the room and
the set temperature.
Fuzzy and integral logic functions then cut in on the basis of
parameters derived from the previous periods of operation (such as
the speed of ambient temperature variation in relation to exterior
conditions) to regulate the required operating power. In a certain
sense the unit “recalls” the previous operating modes, then uses the
information to program the time necessary to reach the ideal
conditions of ambient comfort.
When the ambient temperature approaches the set value (set point),
the conditioner unit reduces frequency so that the setting can be
reached accurately. Once the required ambient conditions are
reached, compressor speed is reduced to operate in the conditions
of maximum efficiency. In the event of heat load variation, frequency
is adjusted to maintain a constant ambient temperature. To prevent
icing of the indoor coil or the delivery of excessively cold air,
compressor speed is limited in accordance with the settings made
by the user.
In the case of heat pump versions, the frequency adjustment
function allows the unit to maintain exactly the required power yield,
even in the event of a drop in the outdoor temperature. Defrosting is
also optimised to achieve an even greater heat yield over time. Icing
of the outdoor coil is controlled by checking the temperature of
outdoor air and of the heat exchanger; defrosting is thereby
performed only when necessary and in the shortest possible time.
The operating frequency of the conditioner is further determined by
refrigerant cycle yield optimisation algorithms, as well as by criteria
of reliability and the fault prevention. During conditioner operation,
all operating parameters are constantly monitored, while automatic
adjustment functions guarantee operation even in conditions of
lower efficiency (i.e. outside min. and max. operating limits).
Unit operating frequency is determined by the following parameters:
– Operating conditions of heat exchangers. During the cooling
refrigerant power output), or when the temperature of the outdoor
exchanger is too high (indicating excess operating pressure). In
the case of heat pump versions, during the heating cycle the
temperature of the indoor exchanger is monitored to detect
excess operating pressure levels.
when the factory-set temperature limit is approached.
could impair correct machine operation is reached.
cut-ins and cut-outs, the elimination of overcompensating settings
and enhanced heat pump defrosting, adding up to greater ambient
comfort and energy savings, and therefore economical operation.
power output requirements, can also be regulated by the following
1 Prevention of indoor exchanger freezing during cooling
5 Maximum temperature control of the compressor power module;
6 Compressor maximum absorbed current control.
Besides the above controls of compressor frequency, the
conditioning unit features other controls which guarantee reliable
operation and greater conditions of comfort.
programmed. This control prevents the delivery of excessively
cold air into the room.
delivery of insufficiently warm air into the room.
dimensioned according to the field of power outputs available,
within the minimum and maximum frequency limits of the
When the conditioning unit is switched on, maximum power output
is automatically available to reach the required conditions rapidly,
especially in the case of particularly large heat loads. During
standard unit operation, power output is determined by ambient
conditions and therefore cannot be pre-determined; tables 1, 2, 3
and 4 show the field of power output variation according to the
external temperature over the range of available compressor
frequencies, pre-set ambient temperature and maximum internal
fan speed, during summer and winter mode applications.
For medium and minimum speed values, see the correction factors
given in table A.
For minimum and maximum yield values and absorption, see the
tables given in Specifications section.
Given the safety devices installed on the unit, operation outside
the above limits is possible for short periods.
When relative humidity is greater than 80%, condensate may
form on air delivery when the unit operates continuously in the
cooling or dehumidification modes.
Table B shows refrigerant line specifications (tube diameter,
Table C shows electrical connection specifications (wire section,
circuit breaker size).
Dimensional data, weights, refrigerant line connections and
technical clearances are shown in the figures below.
complete with nuts and bolts.
possible. Comprises tank and pump unit. In the event of operation
fault, a safety device cuts in to shut down operation.