Carrier 50FC 020-099, Инструкции по установке, эксплуатации и обслуживанию, Страница: 36 / 80

36
Filter fouling detection (optional)
Di
ff
erential pressostat for detection of the
fi
lter fouling level.
This pressostat is installed in the factory:
■
In the electric cabinet, for “Standard” models.
■
On a panel next to the indoor coil, for “In-line” models.
Pressure reading is done thanks to two
intakes within the air flow, such that a
comparison is made between the pressure
of the inlet air to the
fi
lter (positive) and the
supply air of the same to the other side of
the coil (negative).
The electronic control allows the settings
selection for the clogged
fi
lter alarm: only
indication (by default) or unit stoppage.
Manual reset.
The pressostat set value for alarm signalling is con
fi
gured in
factory, depending on the
fi
lters selected for the unit, according
to the following criterion (Standard EN 13053):
■
Unit
fi
lter: the set value is the pressure drop for the
fi
lter
classi
fi
cation, according to the attached table.
■
Serial
fi
lters: the set value is the pressure drop of the highest
e
ffi
ciency
fi
lter + half of the pressure drop of the other
fi
lter,
according to the attached table.
Important: This safety device is particularly recommended with
gas burner.
Filter classi
fi
cation Pressure drop (Pa)
G4 150
M6 / F7 250
F8 / F9 350
Note: all filter frames have a sticker indicating the filter
classi
fi
cation.
11 - SAFETY ELEMENTS
Control of air
fl
ow
The supply plug-fans adapt their speed to the average
fl
ow
measured by the di
ff
erential pressure sensor and the value set
as a setpoint in the electronic control.
Main door switch
By using a mechanical device,
it impedes access to the
electrical cabinet when the
unit is with voltage.
High pressure switch
Connected to the compressor discharge, it will stop its operation
when the pressure at that point reaches the setpoint. It is
automatically reactivated.
Speci
fi
ed pressure to activate switch:
●
R-410A: 42,0 bar.
●
R-454B: 40,5 bar.
Protection for power lines
Protection for power lines of compressors with manual motor
starters and power lines of fan motors with magnetothermic
switches.
These devices provide protection against overload, short circuit,
phase failure and undervoltage.
Low pressure safety
The low pressure safety is done by the “50FC” electronic control
via the measure of the low pressure transducer.
Automatic switch in the control circuit
Magnetothermal switch that protects the operation circuit against
continuous surges as well as against high currents of short duration
(short circuits).
Safety valve
All models include a safety valve in the high pressure line. Valve
tare value at 45 bar.
Note: The activation value of the safety is the same for R-410A
and R-454B, as both refrigerants have similar working pressures.
Caution: Avoid the valve triggering direction
Defrost control
This safety device is intended to eliminate ice which could
accumulate in the outdoor coil when the unit is working in heating
mode.
Defrosting is carried out by the control depending on the outdoor
temperature and the value measured by the low pressure
transducer.
Safeties at the compressors
■
These units have a klixon switch on the compressor discharge
which stops the operation of the motor when there is excessive
heating.
■
Compressor lock: In the event of a power cut-o
ff
for a period
longer than 2 hours, the compressors will be locked. The unit
must remain 8 hours consecutively with voltage to unlock the
compressors. A warning screen on the graphic terminal shows
the remaining time until the end of the locking.
Condensation and evaporation pressure control
This safety, integrated in the control, enables managing the outdoor
fans when the units are working in cooling mode with low outdoor
temperatures (condensation control) or in heating mode with high
outdoor temperatures (evaporation control). This aids the unit’s
operation in all the seasons.
With electronic axial fans, the speed control is proportional, based
on the average pressure measured by the pressure transducers.
■
High temperature safety in tandem compressors (optional):
Working in COOLING mode, when the outdoor coil pressure
of a circuit overcomes a limit value one of the two compressors
will be stopped, thereby avoiding the stop of both compressors
due to the high pressure. This compressor will start working
again if the pressure drops below a safety value.
Refrigerant leak control
Possible refrigerant leakage in case of low pressure alarm.
Although sometimes the alarm has other reasons, the control
allows to detect possible leakage, improving the protection of the
environment.