D – 508 C – 07/02 D – EN pag. 26/36
Heat Recovery Microprocessor Control
All the units equipped with heat recovery water condensers have an additional “microprocessor control” to manage
the heat recovery function of the unit.
The microprocessor is installed inside the main control box, below the controller key pad. (see the picture below)
We use two different models of microprocessor control.
IR32W units with two heat recovery condensers
IR32Z units with three or four heat recovery condensers
Both models are equipped with NTC PT100 temperature sensors to control the inlet water temperature of the
heat recovery condenser and to measure the hot outlet water temperature.
The temperature sensors are supplied electrically connected to the microprocessor but not fitted in the pipe
well pockets; the installation must be done locally by the installer.
The identification of the sensors goes as follows:
“W10” to be installed at the condenser inlet
“W11” to be installed at the condenser outlet
Function
When the heat recovery mode is enabled by the selector switch Q7, if the sensor “W10” reads a water
temperature value below the current setpoint, the control will allow the first stage to switch the four-way valve
from chiller to heat recovery position.
If the setpoint temperature is not achieved, the microprocessor will activate the rest of control stages that,
depending on the number of refrigerant circuits, are available. On the contrary, if the water temperature
exceeds the setpoint value, the microprocessor will switch off control stages until the temperature is within
the regulation band.
Of course it is mandatory that the heat recovery condenser flow switch is on, otherwise the unit will not
enable the heat recovery cycle.
The Microprocessor control is normally set at the factory. To verify or change the setpoints, please refer to
the user manual supplied with the unit.
Heat Recovery Operation
The units supplied with heat recovery condensers are equipped with an additional microprocessor (TC10, see
electrical wiring diagram) for hot water temperature control, featuring two, three or four control stages depending
on the number of heat exchangers installed on the unit (one stage per compressor). For information on how to set
Key Pad
Chiller Operation
HEAT RECOVERY
OPERATION
Switch Selector “Q7”
“0” Cooling Mode
“1” Heat Recovery
Mod
e
Heat Recovery
Microprocessor
Control
Carel type “ IR32”