2. Control Functions
Control of Master/Slave group
SMGB0082 rev.1 - 07/2015
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2
5 About mixing of heat pump machines
It is possible to install heat pump units and cooling-only units in the same group. In that case, operation becomes as
follows:
Cooling operation:
All the chiller units become target of the control of number of units.
Heating operation
Only the heat pump units become target of the control of number of units. Cooling only machines become detached.
1
2
3
4
5
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8
1
2
3
4
5
6
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8
1
2
3
4
5
6
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8
Group of 8 units
Example of 5 heat pump units and 3 cooling-only units
Heat pump units
Cooling-only units
Target of the control of number of units
Target of the control of number of units
Detached
Cooling
operation
Heating
operation
C A U T I O N
• When cooling operation is requested after a heating operation period, each cooling-only machine has to be recovered
to system from detachment state, as described in previous point 2.
N O T E
• In order to prevent freezing of stopped chiller units (in particular of cooling-only units during heating operation in winter),
pump operation order has to be output automatically to keep flow clear.
• In case of combining different types of machine, please se a Heat pump machine as Unit 1.
6 Rotation Control
When starting up the modules, the modules with the shortest operation time have priority. (Comparison is carried out
between units with the same priority order settings, though) When stopping modules, the modules with the longest
operation time have priority. If the operation with the minimum number of operating units continues for a long time,
forced rotation control is conducted.
7 Priority order setting
It is possible to set the desired order of priority in
operation, when there are machines with different
capacities or when inverter type and continuous control
type are mixed together. (Maximum 8 steps)
In this case, module 1 is operated first, as it has the
highest priority, and then a rotation control is performed
among modules 2 to 4, which have the same priority
order.
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Module
HP
Priority order setting
8
Function to cancel the control of Master/Slave group
It is possible to cancel the functions to control the number of units when simultaneous thermo ON/OFF of all the units
is required with without performing the control of Master/Slave group. (Possible in 1-pump systems only)
Setting method:
In 1-pump system settings, set both waiting time for effect of addition and waiting time for effect of reduction to "0".
Practical operation
1 At system start-up
First one chiller unit with the highest priority order is started up, and thermo ON/OFF judgement is conducted.
When the conditions to start up the compressor are fulfilled, the rest of modules are started up in sequence.
2 During normal operation
The control of Master/Slave group is not performed.
In case that any module within the same group is set to thermo OFF, the other modules are stopped.
When the conditions for thermo ON are fulfilled, the rest of modules are started up in sequence.
