Carel ?C2SE User Manual page 50

- High temperature alarm delay on power-up
P17: High temperature alarm delay when the control is switched on (power ON), from the remote
ON/OFF contact or from the keypad.
- High pressure alarm from transducer set point
P18: Sets the value beyond which the high pressure alarm is generated. Each circuit will be
managed by its own transducer.
P18= 0:
the function is disabled.
For all other values greater than 3.0, due to the hysteresis (3 bars), the alarm is managed according
to the set value.
- Low system start-up temperature alarm set point
P19:
Represents a threshold for the low temperature (measured by probe B1) alarm, without
hysteresis; it is reset automatically (the alarm relay is not activated and the display shows the
message "ALt").
- System start-up protection for high/low temperature
P20:
If set to 1, this parameter enables the system protection function when starting, both at
power ON and when switching ON from Standby.
In chiller mode (cooling), for values of B1 greater than the set point P19, an alarm is activated and
the unit is not started (display "AHt").
In heat pump mode (heating), for values lower than the set point P19, an alarm is activated and
the unit is not started (display "ALt").
The alarm is reset automatically.
P20=0:
the function is not enabled.
Low pressure alarm waiting time in heat pump
-
P22: Delay in generating the low pressure alarm in heat pump mode
If the pressure remains below 1 bar for the time p22 and the circuit has 2 compressor steps, the
circuit can operate at part load (see P04). This preventive capacity control function remains active
until the pressure rises above F08-F09.
Low pressure alarm waiting time during defrost
-
P23: Delay in generating the low pressure alarm in heat pump mode during defrost
- Deactivate compressors in capacity control for HP and LP
P24: Decide which compressor must be stopped in each circuit during capacity control
P24= 0 stops compressors 1 and 3
P24= 1 stops compressors 2 and 4
- Low pressure alarm set point from transducer
P33:
: Sets the value beyond which the low pressure alarm is generated when the unit is
operating in heat pump mode. Each circuit will be managed according to its own transducer.
P33= 0 the function is disabled.
- Mute alarm relay using "PRg/mute" button
P35=0 the PRG/mute button does not alter the status of the relay, if the alarm is active and in
progress.
P35=1 the PRG/mute button alters the status of the relay even if the alarm is active and in
progress, as if it were a buzzer or a siren.
- High pressure alarm management
P36: the parameter is used to consider the high pressure alarm even when the compressor is
off or consider it only when the compressor is on, depending on whether the pressure switch is
directly connected to the digital input on the controller or via another circuit.
P36=0: high pressure alarm always considered (pressure switch connected directly to the digital input).
P36=1: high pressure alarm considered 2 seconds after starting the compressor.
• Control settings: parameters (r*)
- Cooling set point
r01:
between r13 and r14
r02:
cooling diff erential value of DTE when the unit is fi rst started (autotuning enabled)
- Heating set point (heat pump)
r03:
between r15 and r16
r04: heating diff erential value of DTE when the unit is fi rst started (autotuning enabled)
- Compressor rotation
r05:
The rotation of the compressors allows the operating hours to be balanced either statistically,
using FIFO logic, or absolutely, by counting the eff ective operating hours. Settings:
r05=0: rotation disabled; The customer can use compressors with diff erent power ratings
according to the desired logic or manage the capacity-control functions. The compressors are
started/stopped in proportional mode.
r05=1: rotation with FIFO logic (fi rst ON, fi rst OFF, and vice-versa fi rst OFF, fi rst ON); in this mode
the operating hours are optimised together with the number of starts, even if the compressor
safety times are always respected.
r05=2: rotation with control of operating hours; in this way the compressors will have the same
operating hours, as the compressor with the least operating hours is always started fi rst, again
observing the safety times. This does not however consider FIFO logic and does not optimise the
starts and stops. In the case of capacity controlled compressors (1 per circuit), FIFO logic or timed
operation will refer to the actual circuit and not the compressor valves. If, for example, when capacity
is required from circuit 1, compressor 1 starts fi rst, capacity controlled (not at full capacity), and then
the valve is managed as a second step, so that the compressor will work at maximum effi ciency. If
50 μC 2 SE - +030220426 - rel. 2.1 - 09.06.2010