'操作说明 Hotflow THREE_26_zh.pdf - 第476页

T ranslation of the original ENGLISH 2. DESCRIPTION OF THE COOLING UNIT 451820.66.03_EN 2020-05-05 19 2.4 Safety features The cooling unit has the following safety features: 2.4.1 High pressure limiter (HP) The high pres…

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2. DESCRIPTION OF THE COOLING UNIT ENGLISH Translation of the original
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451820.66.03_EN
2020-05-05
2.2 Water circuit
Depending on requirements, the cooling unit is equipped with one of the three water circuits
described below.
(See RI flow diagram)
2.2.1 Single-circuit system with tank
With its integrated tank, the water circuit is designed as an atmospherically open system. The water
volume in the tank determines the temperature stability of the water outlet temperature. The pump
supplies the water from the tank to the consumer and via the evaporator to the tank.
2.2.2 Dual-circuit system with tank
With its integrated tank, the water circuit is designed as an atmospherically open system. The water
volume in the tank determines the temperature stability of the water outlet temperature.
The primary pump feeds water from the tank/secondary circuit back into the tank via the evaporator.
The secondary pump feeds the water from the tank back into the primary circuit via the consumer.
2.2.3 Pass-through system
The water circuit of the cooling unit is designed as an atmospherically closed system without
purging facilities. The pump feeds the water through the circuit via the evaporator and consumer.
Purging facilities must be implemented in the external water circuit.
2.3 Cooling air supply
The heat output to be extracted while cooling the water in the evaporator, as well as the electrical
drive output of the compressor, is taken up by the refrigerant and released into the cooling air in the
liquefier.
The cooling air is the surrounding air, which is sucked up by the fan(s) via the liquefier, heated up
and blown out at the top.
Unobstructed intake and outlet of cooling air in the specified temperature range must be
ensured, as must an adequate air exchange for extracting heat from the installation location
of the cooling unit.
(See chapter 5 "Installation")
Translation of the original ENGLISH 2. DESCRIPTION OF THE COOLING UNIT
451820.66.03_EN
2020-05-05
19
2.4 Safety features
The cooling unit has the following safety features:
2.4.1 High pressure limiter (HP)
The high pressure limiter protects the cooling unit against unacceptably high operating pressure in
the refrigerant circuit.
In the event of a fault, the HP limiter switches off the cooling unit and indicates the diagnosis on the
control and operating unit.
The cooling unit can only be switched on again once the pressure has been lowered to the set
pressure differential and the Reset button on the limiter has been pressed.
The high-pressure limiter can be accessed via the service side.
Example of high-pressure limiter
Example figure
2.4.2 Mains disconnecting device (main switch)
The cooling unit can be switched off with the main switch in case of emergency.
2.5 Monitoring devices
2.5.1 Low-pressure control device (LP)
The low-pressure control device protects the cooling unit against an unacceptably low operating
pressure in the refrigerant circuit.
In the event of a fault, the monitoring switches off the cooling unit and indicates the diagnosis on the
control and operating unit.
The cooling unit is reactivated automatically with a delay.
2.5.2 Start-up help for winter
The start-up help for winter acts to prevent low-pressure faults when there is a low ambient
temperature during the cooling start-up phase, until normal operating conditions have become
established.
2. DESCRIPTION OF THE COOLING UNIT ENGLISH Translation of the original
20
451820.66.03_EN
2020-05-05
2.5.3 Overload protector for compressor
The compressor is equipped with an overload protector . If the motor current increases in conjunction
with an increase in the winding temperature, the overload protector triggers and the compressor is
switched off. The overload protector resets automatically once the windings have cooled down. The
diagnosis is not displayed on the control and operating unit.
2.5.4 Thermal contact – fan motor
If the motor current increases in conjunction with an increase in the winding temperature, the
thermal contact switches off the cooling.
This diagnosis is displayed on the control and operating unit.
2.5.5 Circuit breaker (compressor, fan, pump)
If the motor current increases or a short circuit occurs, the circuit breaker switches off and interrupts
the power supply.
This diagnosis is displayed on the control and operating unit.
The circuit breakers are located in the control cabinet.
2.5.6 Float switch
The float switch monitors the water fill level in the tank.
The maximum fill level height ensures that temperature stability is maintained in the water outlet.
In the case of a minor water shortage, only a notification is sent to the control and operating unit.
If the fill level drops below the minimum, the pump(s) is/are switched off (dry run protection).
This diagnosis is displayed on the control and operating unit.
2.5.7 Fan control
The condensation pressure is regulated by the switching on and off of individual fans.
This regulation allows adjustment to different operating conditions while maintaining the relatively
constant condensation temperatures.
2.5.8 Control and operating unit
The control and operating unit controls the water circuits and the refrigerant circuit.
The control and operating unit, which displays the water temperatures and status messages,
is generally integrated into the control cabinet door.
2.6 Electrical/control technology
The electronic equipment of the cooling unit is installed in the control cabinet. The control cabinet
houses all the necessary components for the automatic switching, control and regulation operation.
The main electric circuits come in fuse-free design with motor circuit breaker.
The connection of the cooling unit to the consumer is established via a floating interface.
The interface transmits the following signals:
- "Cooler ready"
- "Status message" Continuous signal from cooling unit to consumer
A control and operating unit maintains the water outlet temperature at a constant set temperature by
actuating performance levels in the refrigerant circuit. The current water outlet temperature is
displayed on the control and operating unit.