MAXA i-MAX 0466, Manual

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i-MAX
Industrial inverter air/water heat pump with axial fans
13
Example in cooling operation:
If the difference in temperature between water inlet and outlet is greater than P09 + P10 , the pump will run at maximum speed.
If the difference temperature between water inlet and outlet is less than P09 - 0.2°C , the pump will run the minimum speed.
In the other cases, the pump modulates trying to match the temperature difference with P09 . For the heating mode, the same
considerations are valid with replace only P06 with P09 . Please see paragraph 11.6 for changing the parameters.
Warning: During the DHW production mode, the pump is constrained to operate at its maximum speed.
In domestic hot water production mode, the pump will operate at the maximum speed.
7.2.6 AIR PURGING OF THE SYSTEM
This function allows the air purging of the system, during this operation, the circulator runs at its maximum speed.
To enable the function:
• Put the controller in
OFF
mode
• Enter at the parameters PRG

PSS

PRG

(introduce the maintainer password)
• Press simultaneously for
3 seconds
the buttons
UP and DOWN.
The circulator of the plant will run at the maximum speed for 5 minutes then it stops the operation.
It is possible to stop manually the air purge cycle function of the system by pressing the MODE / ESC button, or by pressing
simultaneously the UP and DOWN buttons for 3 seconds.
During this function, the flow-switch alarm is deactivated.
7.3 COMPRESSORS CONTROL
The i-Max system uses two refrigerant circuits; each circuit is composed by an inverter compressor and by one or two other on/off
compressors. Follow the activation logic of compressors.
7.3.1 TRANSITORY OF STARTING
When the compressors are all off, in conjunction with the pre-opening of the expansion valve, the reversing valve is commutated
in the opposite direction to that required by the actual mode for 5 seconds in order to allow the equilibrium of the optimal
pressures for starting the first capacity step.
The modulating compressor will always be the first compressor to be start and the last one to stop operation.
The activation and control logic of the modulating compressor follows the thermoregulation curve.
Below are reported the phases of activation and shutdown logic of the other compressors and the behaviour of the modulating
compressor during these phases
7.3.2 ON-OFF compressors activation logic
The ON/OFF compressor starts operation when the required power consumption for the modulating compressor is higher than
90% for a continuous duration given by b16 (default 60 seconds).
The activation of the compressor can occur in 3 steps:
1. Reduction of the output capacity of the modulating compressor to the minimum frequency.
2. Activation of the first ON/OFF compressor when the frequency of the modulating compressor has achieved 45Hz.
3. Activation of second ON/OFF compressor after 10 seconds.
4. The compressor restarts modulation by mean of the thermoregulator after 30 seconds from the ON/OFF compressor
start up.
The unavailability of activation of an On/Off compressor could be also caused by the logic related to the protection or capacity
limitations of the compressor.
7.3.3 Release logic of the ON/OFF compressors
If the thermoregulation that is required for the modulating compressor is corresponding to the minimum needed output capacity
for a period less than 60s, an ON/OFF compressor will stop operation and once the shutdown is completed, the next ON/OFF
compressor will stop also operation after the usual duration of 60 seconds.
Note : In the case in which the regulation temperature is found to be lower than Set - b05 , the release of the running compressors
occurs simultaneously.