Daikin UATYA-B, Operation Manual

Page: 83 / 126

83
Service manual Daikin R32 Rooftops UATYA-B
ESIE21-02 – 2021.03
3.18 Other functions
The unit can be managed automatically based on time bands. The controller manages a set of useful functions for unit
operation.
3.18.1 Management of control probe error
The temperature control probes include a probe that measures the air temperature in the delivery line and a probe that
measures the air temperature in the return line.
If a fault is experienced during unit operation, the controller features an emergency management function in order to provide
for service continuity.
Where a fault occurs, the controller takes as reference the average calculated using the values measured in the past thirty
minutes.
The controller stops the unit if the available measurements cover a shorter period than thirty minutes.
3.18.2 Heater in condensate drip tray
The condensate drip tray may be supplied with a heater to prevent water in it from freezing.
The controller starts the heater in the condensate drip tray as soon as the air temperature is lower than the setpoint in pa-
rameter “STH146”.
The heater is active until the air temperature exceeds the value resulting from the sum of the setpoints in parameters
“STH146” and “STH147”.
If the setpoint in parameter “STH148” is “0”, the heater is only enabled when the unit is in operation; when it is set to “1”, the
heater is also enabled when the unit is off.
3.18.3 "Leak detector" management
The controller manages a refrigerant gas detector serially and it monitors its correct operation.
If malfunctions or refrigerant leaks are identified, the controller triggers alarm messages and safety procedures.
The purpose of the safety procedures is to blow away any refrigerant detected using the fans.
In addition to identifying refrigerant leaks, the controller also manages the following:
- correct serial communication;
- fault events experienced by the detector sensor;
- maintenance of the detector sensor.
The parameters involved are shown in the table.
The values of the parameters are representative. In specific cases, different values can be set.
Parameter Value UM Description
FA25 750 10m3/h Leak detector - Flow rate setpoint
RFA25 750 10m3/h Leak detector - Flow rate setpoint
PAL20 2 - Refrigerant leak - Action in presence of an alarm
PAL21 5 s Refrigerant leak - Delay upon activation
PAL22 5 min Refrigerant leak - Delay upon de-activation
PAL23 0 - Refrigerant leak - Max. number of alarms per hour
The controller activates a “refrigerant leak” alarm if it senses leaking refrigerant for the time set in parameter “PAL21”.
When the “refrigerant leak” alarm is active, the controller:
- it stops all devices in operation, except for the fans (in both delivery and return lines, where applicable);
- sets the dampers for total air recycling;
- it overrides ventilation in the delivery line according to the setpoint in parameter “FA25”;
- it overrides ventilation in the return line according to the setpoint in parameter “RFA25”;
3 Software functions