Sequence Of Operation And Control; Control Operation; Test Sequence - Carrier 30AJ Manual De Instalación, Operación Y Mantenimiento

7.2 - SEQUENCE OF OPERATION AND CONTROL

The following picture shows a drawing of a control board of
all units:
Notes: Before turning on the compressor, the chilled water
pump shall be started.
The unit will start operating automatically when the key
"on" is turned. For more details, check the item "Control
Operation".

7.2.1 - CONTROL OPERATION

When the unit is powered up, all the lights of the control
panel will remain on for 5 seconds. In this status, it is possible
to activate the test mode (see "Test Sequence").
After 5 seconds all the indicators will turn off, except for
the Habilitation. The outputs for the compressors and solenoid
valve will remain off.
Local Mode:
The control will be in this mode when the input IN6 is off.
The IN5 Input will operate to enable and the unit will operate
only if a 24V tension is applied to this input. The unit will turn
on when the on button is pressed and will turn off when the
off button is pressed.
Remote Mode:
The control will be in this mode when the IN6 input is
connected to 24V. The IN5 input will actuate on the unit on/
off. The unit will turn on when 24V is supplied to the IN5 input
and will turn off in case of power supply lack.
For both operation modes, when the unit is put in operation
(pressing the on button or applying 24V to IN5 respectively,
the "on" indicator will light.
The compressor will turn on if no protection is active (anti-
cycling indicators, freezing and pressostat off] and if the
temperature measured by the return water sensor is 1°C
higher then the one indicated in the potentiometer. The return
water is 1°C lower than the set temperature. The solenoid
valve will always turn off together with the compressor and
will turn on 3 seconds before it.
1- Indicator of equipment on
2- Indicator of compressor in operation
3- Indicator of activated anti-recycling timer
4- Indicator of anti-freezing protection on
5- Indicator of open pressostat
6- On button
7- Off button
8- Indicator of enabled power supply
Every stop of the compressor will make the anti-cycling
indicator turn on. While the indicator is on, the compressor
will not start up even if the temperature of the return water
requires it.
The anti-cycling indicator will remain on for four minutes
after the compressor stop. In the last 30 seconds this
indicator will start to shut down, indicating the end of the
anti-cycling period.
The Freezing indicator will turn on if the temperature
measured by the leaving water sensor is lower than 2°C.
This will cause the compressor to stop, the de-activation of
the solenoid valve and the anti-cycling indicator will turn on.
While the freezing indicator is on, the compressor will not
start up again. When the leaving water temperature is higher
than 4°C, the indicator will turn off, allowing the compressor
start-up.
If any pressostat connected to the IN1 input opens, the
Pressostat indicator will turn on, the compressor will stop
and the solenoid valve will be de-activated. The unit will remain
in this status even if the pressostat closes again. In order to
start-up again, the power supply must be turned off for few
seconds and turned on a little later.
The control can operate with a single sensor connected
to the A3 input. In this case, the temperature measured by
this sensor will be used to turn on or off the compressor
according to the set temperature, or to stop the unit due to
freezing.

7.2.2 - TEST SEQUENCE

If P1 and P2 are pressed during the first 5 seconds when
the indicators are on, a test status will start, comprising 10
steps.
During this sequence, the lights L1, L2, L3 and L4 will
exhibit the number of the step within the sequence, while L5
will provide information related to each step.
Every time the P1 button is pressed, one step will be
advanced, until arriving at step 10. If P1 is pressed, the
sequence will restart at sep 1. If, at any moment, P2 is
pressed, one leaves the test sequence and enters in normal
operating status. One also goes to the normal operating
status if, during 3 minutes, no button is pressed.
The sequence steps are:
Step 1: L1, L2 and L3 off, L4 blinks.
L5 will light if the temperature measured by the outside
sensor (connected to A4) is between –5 °C and 15 °C.
Step 2: L1 and L2 off, L3 blinks, L4 off.
L5 will light if the temperature measured by the inside
sensor (connected to A3) is between –5 °C and 15 °C.
Step 3: L1 and L2 off, L3 and L4 blink.
L5 will turn on if there is 24 Vca in the IN4 terminal (input
for the frozen water temperature selection).
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