Refrigerant Circuit Functional Principle; Safety Concept - Pfannenberg DTT 6301 Serie Instructions D'utilisation

GB
2.4.6

Refrigerant circuit functional principle

Item Designation
1 Compressor
3 Expansion valve
5 Condenser fan (external)
7 Electronic control with temperature sensor
The cooling units are comprised of various components; see the figure Refrigerant circuit.
 The compressor (1) compresses the refrigerant under high pressure. The temperature increases.
 This heat is released to the ambient air in the condenser (2). The refrigerant liquefies.
 The condenser fan (5) draws room air through the condenser (2) and releases it to the environment.
 A pressure drop occurs when the refrigerant passes through the expansion valve (3).
 Inside the evaporator (4), the refrigerant absorbs heat from the air inside the switch cabinet and evaporates.
The air inside the switch cabinet is cooled and dehumidified.
 The evaporator fan (6) draws the air from inside the switch cabinet out through the evaporator (4) and releases
the cooled air back to the switch cabinet.
 The cooling units are controlled with a temperature sensor (7). It detects the air temperature inside the switch
cabinet.
2.4.7

Safety concept

WARNING
Danger due to modified safety equipment
Non-functioning or defective safety equipment can cause severe accidents.
 Any changes to the unit, particularly the safety equipment, are prohibited.
 In case of defective safety equipment, shut down the unit and decommission it immediately.
•
Cooling units have a pressure switch tested in accordance with EN 12263. It reacts to a pressure increase in the
refrigerant circuit by shutting off automatically.
•
Fans and compressors are protected from overloading and overheating: e.g. the compressor is protected
against overclocking.
Additional protective functions (only cooling units with anti-freeze option):
 If there is a risk of ice formation, switch off the compressor and the fans.
 This shut-off function is not withdrawn until a system restart.
Operating Manual DTT 6301 Standard Controller (SC) 086100026 © Pfannenberg GmbH
5
3
2
1
Figure 10 - Refrigerant circuit
Item
2
4
6
6
4
7
Designation
Liquefier
Evaporator
Evaporator fan (internal)
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