Operating manual
Document nr. : 022091
Version : V2.3
MC 785-SC
Client : General
Page : 8 of 32
The DISCHARGE part (condenser-side):
Readout selection on the DISCHARGE display.
By pressing the right
SELECT
key next to the DISCHARGE display once or more, the following
values can be shown on the display:
S
The discharge pressure in Bars, LED Bar next to the display lights up.
S
The calculated discharge temperature (depends on coolant) in degrees Celsius, LED’s
Bar and
O
C light up.
S
The discharge temperature, of temperature sensor-2, in degrees Celsius, LED
O
C lights
up.
S
The operation hours of one of the condensers, to select another condenser, press the
right
UP
or
DOWN
keys. To show which condenser has been selected for readout, the
corresponding LED in the condenser bar will light up and the LED Hrs. will light up.
S
Current control signal in percentage, LED % lights up.
Further, there are two more LEDs (
and
) in the DISCHARGE display panel. These LEDs
indicate if the control signal is increasing or decreasing the condenser power.
Showing status of the condensers.
In the CONDENSER panel the status of the condensers is shown in different ways which can
be selected by the right
MODE/SELECT
key. These readout modes are:
S
Normally the LEDs Service and Fail will not be lit, then the LED bars indicate:
Upper LED bar shows which condensers are active.
Lower LED bar shows which condensers are running in time delay.
Or
S
LEDs Service and Fail are lit, then the LED bars indicate:
Upper LED bar shows which condenser is in service.
(These condenser(s) will not be selected for controlling by the controller).
Lower LED bar shows which condenser is in failure.
Readout or changing the discharge pressure (/temperature) setpoint.
By pressing the right
SET
key, the discharge pressure setpoint is shown in the DISCHARGE
display. To indicate this the Bar lights up. By pressing the right
SELECT
key the setpoint will be
shown in degrees Celsius (also adjustable); LEDs Bar and
O
C light up.
To change the setpoint value now press the right
UP
or
DOWN
keys. 10 seconds after the keys
have been released the new setpoint will be active and the controller will return to its normal
display function again. Notice that the controller calculates the temperature signals to pressure
signals and controls on the pressure signals.
Setting a condenser in or out of service.
To put a particular condenser out of function, it must be set in service.
To see which condensers are in service press the
PRG
key together with the right
MODE/SELECT
key. The LED Service will light up and the LED bars show:
Upper LED bar shows which condensers are in service and
Lower LED bar shows the currently-selected condenser.
With the right
UP
and
DOWN
keys another condenser can be selected. The condenser to be
put in or out of service can be put in or out of service by pressing the right
MODE/SELECT
key.
Resetting operation hours of a particular condenser.
Read out the operation hours on the DISCHARGE-display by pressing the right
SELECT
key
once or more, until the LED Hrs lights up. Then select the condenser which has to be set to
zero with the right
UP
and/or
DOWN
keys. Now press the
RESET/ALARM
key, hold it down
and press simultaneously on the right
MODE/SELECT
key to set the selected condenser
operation hours to zero.
