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2.5 Condenser fans
Condensing pressure control is available on DX type units, in which fans are managed based on condensing
coil pressure and compressors state. Fans are enabled by 0-10V modulating or digital outputs. Control is
based on the condensation set point and differential, as shown in the following diagram:
Condensation set
ON
OFF
ON
OFF
The following diagram shows fans operation with modulating outputs:
13.0
The maximum and minimum speeds of 0-10V outputs can be set; in case the set minimum speed is higher
than 0V, the fan is operated at minimum speed 1.0 bar below the condensation set point before switching off,
as indicated in the diagram above.
2.5.1 Single or separate coils
In case of single coil, only one output (on-off or modulating) is enabled. In case of units with at least one
condensing probe and enabled on-off outputs, two on-off outputs may be enabled in sequence, dividing the
differential by two.
In case of separated coils, two different outputs (on-off or modulating) are enabled, one per circuit.
2.5.2 Condensing pressure probes
Foreword: besides the values read by the probes, fans enabling always considers the compressors state.
In case of single probe and separated coils, fans enabling is based on the probe value for both circuits.
In case of two probes and single coil, fans enabling is based on the highest probes value.
In case of two probes and separated coils, fans enabling is based on the probe value of the relevant circuit.
12
CONDENSATION
14.0
16.0
2.0 bar
Condensation differential
0%
14.0
2.0 bar
HP PREVENT
18.0
20.0
2.0 bar
Prevent differential
100%
16.0
Opening start point (100%)
Opening end point (0%)
HP
23.5
24.5
1.0 bar
Condensation
HP differential
pressure (bar)
Compressor
state
Condensing
fans state
Condensation
pressure (bar)
INNOV@-pCO1-IOM-0907-E
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