Evaporator Water Pump Control; Control Interlock Contact; Evaporator Antifreeze Protection - Carrier AQUASNAP 30RB Manual De Controles Y Soluciones De Defectos

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.
ON/OFF CONTROL
STATUS TYPE
Off -
On Local
On Local
On Local
On Local
On Local
On Remote
On Remote
On Remote
On Remote
On Remote
On CCN
On CCN
On CCN
On CCN
On CCN
* Does not apply to cooling only units that do not control a boiler.

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 confi gured (see User confi guration) 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 (confi gurable between 1 and 15 minutes), the
pump will run for at least one minute before the fi rst 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 confi guration), the control tries
to limit the pump run time delta to the confi gured 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.
HEATING/COOLING REMOTE HEATING/
SELECTION IN COOLING CONTACTS
LOCAL MODE
- -
Cooling -
Heating -
Auto -
Auto -
Auto -
- Cooling mode
- Heating mode
- Auto mode
- Auto mode
- Auto mode
- -
- -
- -
- -
- -
• 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
HC_SEL OUTDOOR TEMPERATURE
- -
- -
-
-
- > Cooling threshold
- < Heating threshold
- Between cooling and heating thresholds
- -
- -
- > Cooling threshold
- < Heating threshold
- Between cooling and heating thresholds
Cooling -
Heating -
Auto > Cooling threshold
Auto < Heating threshold
Auto Between cooling and heating thresholds
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 fi tted with two pumps, the fi rst 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 fl ow 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
modifi ed, using the Service confi guration.
OPERATING
MODE
Cooling
Cooling
Heating
Cooling
Heating*
Standby
Cooling
Heating
Cooling
Heating*
Standby
Cooling
Heating
Cooling
Heating*
Standby
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