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17 - CONTROL OF CONDENSING PRESSURE FOR AIR-COOLED UNITS
17.3.1 - Variable speed drive (VSD) :
In order for it to adjust the speed based on the 0-10 V signal, the variable speed drive selected must first be supplied electrically and
informed of the direction of rotation.
► VSD power supply :
Power will be supplied, via the power contactors, by the control for fan 1 on circuit 1 (terminal 5 on terminal block J3), the control for
fan 1 on circuit 2 (terminal 6 on terminal block J3 on additional card 2) and the control for fan 1 common to both circuits (terminal 5 on
terminal block J3 on additional board 2).
In both heating and cooling mode, these three outputs must be powered as soon as the unit is turned on by pressing the On/Off
button on the console or by turning off the Automatic Operation control. They will shut off after the Automatic Operation control is turned
on or if the On/Off button on the console is pressed.
► Authorisation of VSD operation :
External VSDs (ALTIVAR) will not be controlled by the software. Instead, they will be controlled electromechanically via two auxiliary
relays on the KGs of the compressors (as soon as a compressor turns on, the associated relay sends the information to the VSD). As
a result, running the VSDs without the compressors will not be possible.
In the case of electronically commutated fans (built-in variable speed drive), authorisation for the VSDs to turn on is given by the board
when the fan contactor outputs are in the On position (no relay needed).
17.3.2 - Fan speed control with split coils (P11 = split) :
This configuration requires a variable speed drive for each circuit.
- 0-10 V output, stage 1, circuit 1, terminals 1-2 on motherboard terminal block J2
- 0-10 V output, stage 1, circuit 2, terminals 2-1 on terminal block J6 of additional board 2
Speed control mode is turned on as soon as the circuit is on.
a) P21 = 2 with acoustic optimisation
1 condenser fan module per circuit = 1 stage (1 fan) with speed control + 1 single-speed stage (same as standard)
2 condenser fan modules per circuit = 1 stage (2 fans) with speed control + 2 single-speed stages (same as standard)
2
1
V V
b) P21 = 3 with energy optimisation (Available only if P42 = ALCO or VCM)
P181
If P180 = 3 stages: 15-30% and 70-85% for stages 2-3
If P180 = 2 stages: 20 and 80% for stage 2
The values of P181 and P183 must be set.
P181 = 17.8 b for R410A, 12 b for R407C, 11.0 b for R22 and 6.8 b for R134a
P183 = 7.8 b for R410A or 5.5 b for R407C, 5.0 b for R22 and 3.8 b for R134a
In this case parameters P181 and P183 can be adjusted (resolution of 0.1) and parameter P184 becomes needless and therefore
inaccessible.
92
DEE = P183
3
1
P181
DEE = P184
1er = Stage 1, 2ème = Stage 2, 3ème = Stage 3
DEE = Interstage differential
Stage 2
Stage 3
15 %
30 %
1
er
70 % 85 %
P183
2
ème
3
ème
HP bar
Stage 1
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