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17 - CONTROL OF CONDENSING PRESSURE FOR AIR-COOLED UNITS
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 if R410A or 5.5 b if R407C, 5.0 b if R22 and 3.8 b if R134a
In this case parameters P181 and P183 can be adjusted (resolution of 0.1) and parameter P184 becomes needless and therefore
inaccessible.
- The minimum value of P181 becomes 16 bar for R410A.
- The minimum value of P183 becomes 8 bar for R410A.
P181
17.3.5 - Fan speed control if P7 = INVERTER :
- The rotation speed is limited by parameter P192 (default value of 7.8 V). It can be set at between 5 and 10 V (resolution of 0.1 V).
- If P7 = INVERTER, the standard setting value of P181 becomes 13.4 bar as long as LP < 8.3 bar.
- If the LP rises above this value, the HP control setpoint is becomes equal to P181 + 4.4 bar.
- The HP control setpoint returns to P181 when the LP drops to < 7.8 bar.
- The maximum shift in the HP STP is 33.9 bar (recovery function included).
17.3.6 - Forced control of variable-speed fans :
The condensing pressure control can be forced in cooling mode in two cases:
- If HP > P54 – P195 – 0.5, the fans run at maximum speed for 30 minutes and the stages turn on at 3-second intervals.
- During defrosting in order to defrost the coils as quickly as possible. The HP will have to be as high as possible without turning
on the protections.
- Parameter P166 (3 by default) is used to adjust the fan control.
Adjustment adopted during defrosting (once the cycle has been reversed by the reversing valve). The other fans are off during this time.
17.3.7 - Speed control of centrifugal fans (P10 = Centrifugal) :
P21 is hidden. This configuration is not available. The HP is controlled via the air blades. Refer to the section on controlling the air
blades.
94
Stage 2
Stage 3
15 %
30 %
P192
P166 =
1
2
3
0V
P54 - P164 - P165
70 % 85 %
P183
P54 - P164
Stage 1
HP
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