1.2 Operating instructions µC2 (YLHA 50, 60 and 80)
DESCRIPTION OF THE CONTROL UNIT
This is a multipurpose controller specially programmed for use with air-water chillers and heat pumps
equipped with a tandem compressor, two power stages and a single cooling circuit.
Main functions
• Water temperature control (at inlet or outlet, as per parameter r6).
• Defrost cycle management.
• System operating and safety management.
• Fan speed control.
• Alarm management.
• Connection for supervision and remote assistance (accessory serial connection RS485).
Devices controlled
• Compressor
• Fans
• Four-way valve
• Water pump
• Alarm device
• Heaters
STANDARD COMPONENTS
Base control module for the system and the first compressor.
This is the central nucleus that processes the signals coming from the sensors and protection elements
of the entire system to control its active elements: compressors and fans, four-way valve, water circulating
pump, alarm relay and antifreeze heater. Power supply 24 Vac.
It can also be used for access and control of the system by means of the display, buttons and LEDs
available. It allows for selection of cool, heat and off functions. Operating parameters can also be modi‐
fied, and the system can also be supervised.
Expansion and control module for the second compressor
This is an expansion of the base module to which it should be connected by means of two cables. It
controls the operation of the second compressor.
Fan speed control module
Operates by phase cut-off. Includes fuse
NTC and ratiometric (pressure) sensors
3 NTC sensors are used to read system temperatures and a ratiometric pressure transducer (B4) to read
refrigerant pressure inside the coil:
• B1. Controls the set point. Reads water temperature at exchanger inlet.
• B2. Antifreeze control. Reads water temperature at exchanger discharge.
• B3. Controls the dynamic set point. Reads outdoor air temperature.
• B4. Fan speed and defrost cycle control. Reads refrigerant pressure inside the coil.
Parameters
The set of parameters that configure the operating program of the unit is divided into four levels (Factory,
Super User, User and Direct), depending upon the function of each parameter and the user’s access
level. The parameters of each level can be modified from that same level, as well as lower level param‐
eters.
Factory Level
Accessible with the Factory password. Allows configuration of all unit parameters.
Super User Level
Accessible with the Super User password. Allows setting Super User, User and Direct parameters.
User manual
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Operating instructions µC2 (YLHA 50, 60 and 80)
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