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5.3 - EVAPORATOR WATER PUMP CONTROL
The unit can control one or two evaporator water pumps.
The evaporator water pump is turned on when this option
is configured (see User configuration) and when the unit
is in one of the on modes described above or in delay
mode. Since the minimum value for the delay at start-up
is 1 minute (configurable between 1 and 15 minutes), the
pump will run for at least one minute before the first com-
pressor starts. The pump is kept running for 20 seconds
after the unit goes to stop mode. The pump keeps
working when the unit switches from heating to cooling
mode or vice-versa. It is turned off if the unit is shut down
due to an alarm unless the fault is a frost protection error.
The pump can be started in particular operating
conditions when the evaporator heater is active (see
section 5.5). See section 5.14 for the particular evaporator
pump control for the follower unit (master/slave
assembly).
If two pumps are controlled and the reversing function
has been selected (see User 1 configuration), the control
tries to limit the pump run time delta to the configured
pump changeover delay. If this delay has elapsed, the
pump reversing function is activated, when the unit is
running. During the reversing function both pumps run
together for two seconds. Si falla una bomba y hay
disponible una bomba secundaria, la unidad se para y
se pone de nuevo en marcha con la bomba válida.
5.2.2 - HEATING/COOLING/AUTO SELECTION
The table below summarises the unit heating/cooling
operation, based on the following parameters:
✓
Control type:
indicates whether the unit operates
in local, remote or CCN mode. See section 5.1.
✓
Unit on/off status:
indicates whether the unit is shut
down (not authorised to start) or in operation (or
authorised to start).
✓
Heating/cooling/auto selection in local mode:
operating mode selected via the user interface. See
Information menu.
✓
Remote heating/cooling contacts:
these contacts
are only active if the unit is under remote control.
See sections 3.6.2 and 3.6.3.
✓
HC_SEL:
this network command permits heating/
cooling/auto control, if the unit is in CCN operating mode.
✓
Outdoor temperature:
determines the operation, if
the unit is in automatic heating/cooling/standby
changeover mode.
PARAMETER STATUS
ON/OFF
STATUS
Off
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
CONTROL
TYPE
-
Local
Local
Local
Local
Local
Remote
Remote
Remote
Remote
Remote
CCN
CCN
CCN
CCN
CCN
HEATING/COOLING
SELECTION IN
LOCAL MODE
-
Cooling
Heating
Auto
Auto
Auto
-
-
-
-
-
-
-
-
-
-
REMOTE HEATING/
COOLING CONTACTS
-
-
-
-
-
-
Cooling mode
Heating mode
Auto mode
Auto mode
Auto mode
-
-
-
-
-
HC_SEL
-
-
-
-
-
-
-
-
-
-
-
Cooling
Heating
Auto
Auto
Auto
OUTDOOR TEMPERATURE
-
-
-
> Cooling threshold
< Heating threshold
Between cooling and heating thresholds
-
-
> Cooling threshold
< Heating threshold
Between cooling and heating thresholds
-
-
> Cooling threshold
< Heating threshold
Between cooling and heating thresholds
OPERATING
MODE
Cooling
Cooling
Heating
Cooling
Heating*
Standby
Cooling
Heating
Cooling
Heating*
Standby
Cooling
Heating
Cooling
Heating*
Standby
*
Does not apply to cooling only units that do not control a boiler.
If a pump has failed and a secondary pump is available,
the unit is stopped and started again with this pump.
The control provides a means to automatically start the
pump each day at 14.00 hours for 2 seconds when the
unit is off. If the unit is fitted with two pumps, the first
pump is started on odd days and the second pump is
started on even days. Starting the pump periodically for
few seconds increases the life-time of the pump bearings
and the tightness of the pump seal.
5.4 - CONTROL INTERLOCK CONTACT
This contact checks the status of a loop (water flow switch
and customer safety loop, see section 3.6). It prevents
the unit from starting if it is open when the delay at start-
up has expired. This open contact leads to an alarm
shut-down, if the unit is running.
5.5 - EVAPORATOR ANTIFREEZE PROTECTION
The heater for the evaporator and water pump (for units
with a pump) can be energised to protect the evaporator,
if it can be damaged by freezing, when the unit is shut
down for a long time at low outdoor temperature.
NOTE:
Evaporator heater control parameters can be
modified, using the Service configuration.
