Technical information
102
Rotation of compressors
The controller provides a FIFO type rotation in which the first
compressor to go on will be the first to go off as well.
Start-up sequence: C1, C2, C3, C4.
Off sequence: C1, C2, C3, C4.
HP prevent
When this function is enabled, the controller attempts to avoid
the blockage of the unit due to excessively high pressure.
When said pressure reaches a preestablished value near the
off pressure, the controller speeds up the fans to a maximum
(if in cool cycle), or slows them down to a minimum (if in heat
cycle). If the operating pressure continues getting close to the
HP Prevent pressure, the controller turns off a compressor
in the tandem of the affected circuit. The parameters of said
function are accessed from the "Condensation" menu.
Defrost cycle
If the evaporating pressure of one of the systems remains
below the value set for starting defrost during an accumulated
period of time equal to the period established as the delay
between defrosts, simultaneous defrost of all unit coils is
started. The cycle ends once the pressure set as end defrost
is reached, or at the end of the time period set as maximum
duration of the cycle.
The defrost sequence is as follows: 1. Compressors are
turned off. 2. After 15 seconds, the 4-way valves are inverted.
3. After 45 seconds, the compressors go on with the fans off.
4. Once the defrost is over, the compressors go off. 5. After 15
seconds, the 4-way valves are inverted. 6. After 45 seconds,
the compressors and fans start up again.
Control sensors: Pressure transducers B3 and B4.
Parameters used:
- Simultaneous defrost.
- Defrost start pressure.
- Defrost end pressure.
- Defrost call delay.
- Maximum defrost duration.
- Minimum defrost duration.
- Compressor forced off time by cycle inversion.
- 4-way valve inversion delay.
Affected outputs:
- Compressors (N1, N2, N3 and N4).
- 4-way valves (N13 and N14).
- Fans (Y3 and Y4).
DefrOff End defrost pressure
DefrOn Start defrost pressure
Dt 1...3 Partial times of remaining in defrost start pressure zone
DefrAct Defrost active
t Time
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