Technical information

77
Operating Instructions µC2 + Expansion
YLHA 50, 60 and 80
Description of 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 one single
cooling circuit.
Main functions
- Water temperature control (at intake or outlet, as per pa-
rameter r6).
- Defrost cycle management.
- System operating and safety management.
- Fan speed control.
- Alarm management.
- Connection for supervision and telephone assistance (ac-
cessory serial connection RS485).
Devices controlled
- Compressors
- Fans
- Four-way valve
- Water pump
- Alarm device
- Heaters
Standard components
- Control base module for system and the first compres-
sor. - This is the central nucleus that processes the signals
coming from the probes and protection elements of the
entire system to control its active elements: compressor 1,
fans, four-way valve, water circulating pump, alarm relay
and antifreeze heater. Power supply 24 Vac.
Can also be used for access and control of the system by
means of the display, buttons and LEDs available. Allows
selection cool, heat and off functions. Operating parameters
can also be modified, and the system can be supervised
as well.
- Expansion and second compressor control module.-
This is an expansion of the base module to which it should
be connected by means of two cables. It controls the opera-
tion of the second compressor.
- Fan speed control module. Operates by phase cut-off.
Includes fuse.
- NTC and ratiometric (pressure) probes.
3 NTC probes are used to read system temperatures and
a ratiometric pressure transducer (B4) to read refrigerant
pressure inside the coil:
B1. Controls set point. Reads water temperature at ex
-
changer intake.
B2. Antifreeze control. Reads water temperature at ex
-
changer discharge.
B3. Controls dynamic set point. Reads outdoor air tem
-
perature.
B4 and B8. Fan speed and defrost cycle control. Read
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
parameters.
Factory level
Accessible with the Factory password. Allows configuration
of all unit parameters.
Super User level
Accessible with Super User password. Allows setting Super
User, User and Direct parameters.
User level
Accessible with password 22. Allows access to all parameters
the user normally sets.
Direct level
Accessible without a password. Allows reading the values
detected by the probes, as well as other system values. Can
be used by the user without affecting unit operation.
General
Modification of the parameters that affect basic unit configura-
tion should be made with the controller in Standby position.