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1 bar 1,5 bar 2 bar F08-F09

ENGLISH

µC

SE process chiller +030220416 - rel. 1.1 - 27.04.2010

• Alarm settings: parameters (P*)

- Flow switch alarm delay when starting pump

P01: Establishes a delay in the recognition of the ﬂ ow switch alarm when starting the pump (this allows the

ﬂ ow-rate to stabilise). In the event of alarms, the compressors are stopped immediately, ignoring the times.

- Flow switch alarm delay in steady operation

P02: Establishes a delay in the recognition of the ﬂ ow switch alarm in steady operation, so as to ﬁ lter any

variations in ﬂ ow-rate or air bubbles present in the water circuit. In the event of alarms, the compressors

are stopped immediately, ignoring the times.

- Low pressure alarm delay at compressor start

P03: Establishes a delay in the recognition of the low pressure alarm when the compressor starts, so as

to allow stable operating conditions to be reached. This delay is also counted when reversing the 4-way

valve in the refrigerant circuit.

- Part load in high pressure and low pressure in heat pump

P04: enable or disable the part load operation of the circuit in high pressure.

The function is valid if the unit is ﬁ tted with tandem or capacity controlled compressors and pressure

transducers. In the event of high pressure alarms, that is, for values over P18 (hysteresis 0.5 bar), the

controller deactivates a load step in the circuit in question and waits 10 seconds. After this interval, if the

alarm is still active, the unit is stopped, otherwise it continues to operate in part load mode. In this situation,

the display shows the message PH1 and/or PH2, depending on the circuit. This condition remains active

until the pressure falls below the value corresponding to the maximum speed of the condenser fans

(F05+F06). Below this value, the unit reactivates the load step that had previously been deactivated.

P04=0: capacity control not activated

P04=1: capacity control activated for high pressure

P04=2: capacity control activated for low pressure

P04=3: capacity control activated for high and low pressure

With the unit operating in heat pump mode, due to low outside temperatures or the load the pressure may

fall and stop the unit due to the low pressure alarm. If the circuit has 2 compressor steps and the pressure

remains below the value of one bar for the time P22, the circuit can operate at part load. This capacity

control is not activated when the alarm comes from the digital input. In the event of low pressure, the

controller deactivates one step and if the pressure does not return above the threshold in 10 seconds, the

alarm is activated and the circuit is stopped. This function is valid for all units with pressure transducers.

- Alarm reset

P05: Enables automatic reset for all those alarms that normally feature manual reset (high pressure, low

pressure, ﬂ ow switch/antifreeze) as per the following table:

P05= 0: (default) high pressure, low pressure and antifreeze (low temperature) with manual reset;

P05= 1: all the alarms with automatic reset;

P05= 2: high pressure and antifreeze (low temperature) manual, low pressure automatic;

P05= 3: high pressure manual, low pressure and antifreeze (low temperature) automatic;

P05= 4: high and low pressure manual, antifreeze (low temperature) automatic;

P05= 5: high and low pressure manual after the third activation in one hour*, antifreeze (low temperature)

automatic;

P05= 6: high and low pressure manual after the third activation in one hour*, antifreeze (low temperature) manual.

- Low pressure alarm with pressure probes

P07: P07=0: this function is disabled.

P07=1: if in heat pump mode the evaporator (external exchanger) pressure is less than 1 bar (and if the

presence of the condenser pressure probe is enabled), the low pressure alarm is activated (while still

considering the delay P03).

Note: P07=1 the LP digital inputs in heat pump are ignored.

- Select digital input ID1

P08= 0: none;

P08= 1: ﬂ ow switch with manual reset (normally closed);

P08= 2: ﬂ ow switch with automatic reset (N.C.);

P08= 3: general thermal overload with manual reset (N.C.);

P08= 4: general thermal overload with automatic reset (N.C.);

P08= 5: thermal overload circuit 1 with manual reset (N.C.);

P08= 6: thermal overload circuit 1 with automatic reset (N.C.);

P08= 7: thermal overload circuit 2 with manual reset (N.C.);

P08= 8: thermal overload circuit 2 with automatic reset (N.C.);

P08= 9: cooling/heating (open = Cooling, closed = Heating) if H06= 1;

P08= 10: cooling/heating with delays d12 and d13 (open = Cooling, closed = Heating) if H06= 1;

P08= 11: alarm signal with manual reset (N.C.);

P08= 12: alarm signal with automatic reset (N.C.);

P08= 13: second set point from external contact (cooling and heating), (normally open);

P08= 14: second cooling set point from external contact and heating from time band (N.O.);

P08= 15: end defrost from external contact circuit 1 (N.C.);

P08= 16: end defrost from external contact circuit 2 (N.C.);

P08= 17: end defrost from external contact circuit 1 (N.C.);

P08= 18: end defrost from external contact circuit 2 (N.C.);

P08= 19: condenser step 1 (N.O.);

P08= 20: condenser step 2 (N.O.);

P08= 21: condenser step 3 (N.O.);

P08= 22: condenser step 4 (N.O.);

P08= 23: remote ON/OFF.

*: the high and low pressure alarms are managed in the

same way both for the transducers and the pressure switches

(digital input); if the unit is in standby the count (3 times in

one hour) is reset.

note 1: if P08 is set to 10, the change in state considers the

times d12 and d13, and respects the compressor protection

times, both from the digital input and the keypad.

note 2: if the digital input is used to switch the unit ON/OFF

or change the operating mode, these functions are disabled

on the keypad.

note 3: ID5 for the condensing unit with reverse cycle has

the function of cooling/heating changeover

Fig. 5.b.b

all LP

pressure

Part load in low pressure

parz LP