LOCAL OPERATING MODE
PARAMETER STATUS
HEATING/ | LOCAL | SCHEDULE 2 | ACTIVE SETPOINT |
COOLING | SETPOINT | PROGRAM STATUS |
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OPERATING | SELECTION |
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MODE |
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cooling | sp 1 | - | cooling setpoint 1 |
cooling | sp2 | - | cooling setpoint 2 |
heating | - | - | heating setpoint |
holidays | auto | occupied | cooling setpoint 1 |
holidays | auto | unoccupied | cooling setpoint 2 |
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REMOTE OPERATING MODE |
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PARAMETER STATUS |
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HEATING/ | CONTROL | SCHEDULE 2 | ACTIVE SETPOINT |
COOLING | CONTACT | PROGRAM STATUS |
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OPOERATING |
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MODE |
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heating | - | - | heating setpoint |
cooling | sp 1 | - | cooling setpoint 1 |
cooling | sp2 | - | cooling setpoint 2 |
- | holidays | occupied | cooling setpoint 1 |
- | holidays | unoccupied | cooling setpoint 2 |
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CCN OPERATING MODE |
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PARAMETER STATUS |
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HEATING/COOLING | SCHEDULE 2 | ACTIVE SETPOINT | |
OPERATING MODE | PROGRAM STATUS |
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cooling |
| occupied | cooling setpoint 1 |
cooling |
| unoccupied | cooling setpoint 2 |
heating |
| - | heating setpoint |
5.17 - High pressure load shedding function
This function does not require an additional board. It prevents high pressure a break on a circuit by the following means:
•Preventing any capacity increase on the circuit once the high pressure value has reached an initial threshold.
•Shedding one or more capacity stages once a second protection threshold has been reached.
In the event of capacity stages being shed, no capacity increase will be authorised on the circuit concerned for a period of 5 minutes.
5.18 - Pumping down
When the lead compressor in each circuit is started or stopped, that circuit goes through a pumping down cycle to purge the evaporator and suction line of refrigerant. The maximum duration of this cycle is 3 minutes.
5.19 - Master/slave assembly
Two
Master/slave operation requires the connection of a temperature probe at the common manifold on each machine, if the heat exchanger leaving water temperature is controlled.
The master/slave assembly can operate with constant or variable flow. In the case of variable flow each machine must control its own water pump and automatically shut down the pump, if the cooling capacity is zero. For constant flow operation the pumps for each unit are continuously operating, if the system is opera- ting. The master unit can control a common pump that will be activated, when the system is started. In this case the slave unit pump is not used.
All control commands to the master/slave assembly (start/stop, setpoint, heating/cooling operation, load shedding, etc.) are handled by the unit which is configured as the master, and must therefore only be applied to the master unit. They will be trans- mitted automatically to the slave unit. The master unit can be controlled locally, remotely or by CCN commands. Therefore to start up the assembly, simply validate the Master operating type (MASt) on the master unit. If the Master has been confi- gured for remote control then use the remote
One of the functions of the master unit (depending on its con- figuration) may be the designation, whether the master or slave is to be the lead machine or the follower. The roles of lead machine and follower will be reversed when the difference in running hours between the two units exceeds a configurable value, ensuring that the running times of the two units are automatically equalised. The changeover between lead machine and follower may take place when the assembly is started up, or even whilst running. The running time balancing function is not active if it has not been configured: in this case the lead machine is always the master unit.
The lead machine will always be started first. When the lead machine is at its full available capacity,
In the event of a communication fault between the two units, each shall return to an autonomous operating mode until the fault is cleared. If the master unit is halted due to an alarm, the slave unit is authorised to start without prior conditions.
5.20- Controlling Pro-Dialog Plus units with a System Manager
Up to eight
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