REFCO LAC Extreme User Manual [en, de, fr, it]
HVAC/R
Service Products
INSTALLATION OPERATION
AND MAINTENANCE GUIDE
LAC EXTREME
Cooling only, Heat pump and Low Temperature Cut-Off Models
The HPC controllers modulate the condenser fan speed to maintain a constant condensing pressure in heat pumps, air conditioners and refrigeration
plant. This results in higher efficiency, shorter compressor running times,
and more-stable conditions on the evaporator. Over-condensing is eliminated, and freeze-up of air conditioner indoor units is prevented.
COOLING OPERATION
Controlling air movement over the condenser by varying the fan speed
maintains a constant condensing temperature, therefore a constant head
pressure. The condenser temperature is measured midway through the circuit, where the hot gas is condensing. As the condenser temperature rises
and falls, the fan speed automatically increases and slows down to maintain
the head pressure at the set point level. When first powered in the fan runs
at full speed for 10 seconds before controlling to temperature. Note: low
temperature cut-off models need to measure within range before start up.
As temperatures drop the fan speed will fall to its minimum speed. Low
temperatures cut-off models switch off the fan if the temperature continues
to drop: a temperature rise will initiate a 2 second full speed re-start to get
the fan moving. Dual circuit systems are accommodated by the 2-sensor
model where controller responds to the higher of the two temperatures.
Fig. 1 Application Example
REFCO Manufacturing Ltd. Telefon +41 41 919 72 82
Industriestrasse 11 Telefax +41 41 919 72 83
CH-6285 Hitzkirch (Switzerland) Info@refco.ch www.refco.ch
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HEATING MODE OPERATION
Heat pump models incorporate terminals for connection to the reversing
solenoid valve. The controller is configured to automatically produce 100%
fan speed in heating mode with the reversing valve energised.
SAFETY FIRST
Disconnect all power supplies before starting installation or maintenance
work. The controller and sensor are to be safely enclosed within the housing of the condensing unit, or other enclosure. The controller must be fitted in a dry location, where water cannot fall in to it, or be blown on to it by
the moving fan. The plastic enclosure of the controller is designed to protect
the internal components. There are no user-serviceable parts. All electrical
wiring must be carried out by a competent person, and must comply with
all National and Local Electrical Codes.
FITTING THE CONTROLLER
The Controller should be mounted inside the outdoor unit, protected from
any water dripping on to it, or blown by the fan. The Controller must be
secured to a flat even surface.
WIRING THE CONTROLLER
Fig. 2 illustrates the preferred wiring of the Controller. However some fan
motors may control more smoothly when as in Fig. 3.
Fig. 2 Preferred Motor Wiring Fig. 3 Alternative Wiring
REFCO Manufacturing Ltd. Telefon +41 41 919 72 82
Industriestrasse 11 Telefax +41 41 919 72 83
CH-6285 Hitzkirch (Switzerland) Info@refco.ch www.refco.ch
HVAC/R
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Fitting the Sensor
The HPC sensor is fitted to one of the return bends typically mid-way
through the condenser coil circuit, where it can pick up the temperature
of the condensing gas. Wrap tie around twice for small tubes. Use a heat
sink compound between the sensor and the tune for a good thermal bond.
Insulate using foam tape. Do not over-tighten as damage can be caused
to the sensor bead, which is protected by a thin black insulating sleeve is
damaged. On two-sensor models, each sensor should be fitted to its own
section of the condenser, in the centre of the condensing circuit.
Heat pump Models
Where the head pressure controller is to be used with a heat pump, the condenser fan needs to run at full speed during the heating mode, and is only
modulated during the cooling mode. The controller used with heat pumps
therefore have 2 extra terminals which are connected across the reversing
solenoid valve. These then receive a signal feed from either solenoid which
is energised to switch on to heating, and this signal causes the controller to
run the fan at full speed.
Setting Up
The control range of the controller is 30°C to 60°C, and the set point is adjusted by means of the control spindle on the face of the controller. Minimum
speed is factory set for 50Hz operation as standard. Product marked with a
yellow sticker adjacent to the adjuster, indicates that the controller is configured for 60Hz operation. Therefore no further adjustment is necessary.
The minimum fan speed is factory-set to give a motor voltage of 100V for
230V models and 60V for 110V models, which produce a speed of around
30% of maximum, depending in the motor characteristics. Minimum speed
adjustment on low temperature cut-off Models is not advised. To adjust minimum speed, disconnect sensor and switch on unit, fan automatically runs
at minimum speed after hard start, adjust carefully until the fan is running
just fast enough to prevent stalling in windy conditions. Switch off and reconnect sensor.
REFCO Manufacturing Ltd. Telefon +41 41 919 72 82
Industriestrasse 11 Telefax +41 41 919 72 83
CH-6285 Hitzkirch (Switzerland) Info@refco.ch www.refco.ch
HVAC/R
Service Products
BEDIENUNGS- UND
WARTUNGSANLEITUNG
LAC EXTREME
Modelle nur für Kühlung, sowie für Wärmepumpen und für die Abschaltung bei niedrigen Temperaturen
HPC-Steuerungen werden zum Abgleich der Lüfterdrehzahl des Kondensators eingesetzt, um einen konstanten Kondensationsdruck in Wärmepumpen, Klimageräten und Kälteanlagen zu erhalten. Dies ermöglicht grössere
Effizienz, kürzerer Kompressor-Betriebszeiten und stabilere Bedingungen
beim Verdampfer. Überkondensation wird vermieden und dem Einfrieren
von Innen-Klimageräten vorgebeugt.
KÜHLBETRIEB
Die Steuerung des Luftstroms über dem Kondensator durch Variieren der
Lüfterdrehzahl ermöglicht eine konstante Kondensationstemperatur und
damit einen konstanten Wasserdruck. Die Kondensations-temperatur wird
auf halber Strecke des Kreislaufs, an der Stelle an der das Heissgas kondensiert, gemessen. Mit steigender und fallender Kondensationstemperatur
steigt die Lüfterdrehzahl automatisch an bzw. fällt automatisch ab, um den
Wasserdruck auf dem Sollwert-Niveau zu halten. Beim ersten Einschalten
läuft der Lüfter zunächst 10 Sekunden lang mit höchster Drehzahl und steuert dann die Temperatur. Hinweis: Modelle zum Abschalten bei niedrigen
Temperaturen müssen vor dem Start innerhalb des Bereichs messen. Mit
fallenden Temperaturen wird die Lüfterdrehzahl bis zur Mindestdrehzahl
verringert. Modelle zum Abschalten bei niedrigen Temperaturen schalten
den Lüfter bei anhaltend fallenden Temperaturen ab: ein Temperaturanstieg
löst einen Neustart mit Betrieb bei höchster Drehzahl für 2 Sekunden aus,
um den Lüfter wieder in Bewegung zu bringen. Das Modell mit 2 Sensoren
enthält ein Zweikreissystem, bei dem die Steuerung auf die höhere der beiden Temperaturen anspricht.
Abb. 1
Anwendungsbeispiel
REFCO Manufacturing Ltd. Telefon +41 41 919 72 82
Industriestrasse 11 Telefax +41 41 919 72 83
CH-6285 Hitzkirch (Switzerland) Info@refco.ch www.refco.ch
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