Tech Controllers ST-53.4, Руководство пользователя

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When delta exceeds the threshold value ( UNFREEZING DELTA ) the defrosting function is activated. But if the activation delta value
is lower than the threshold value, the controller waits for a specified time ( FORCED DEFROSTING TIME ) before activating the
defrosting function – after this time, unfreezing is activated.
Defrosting continues until the evaporator's temperature grows to a certain value ( DEFROSTING END TEMPERATURE ). If the
evaporator's temperature is still not growing, the controller will switch off all the devices after the lapse of a specified time
(
MAXIMUM DEFROSTING TIME ). The next defrosting attempt is made after the lapse of the compressor downtime. After the end
of the defrosting process, the controller switches to downtime.
6.2.1
TURN DEFROSTING ON
The option allows you to activate the defrosting process.
6.2.2
MANUAL DEFROSTING
This parameter allows you to manually switch on the defrosting process, ignoring the fulfillment of some conditions ( DEFROSTING
DELTA, BLOCKED DEFROSTING TIME and FORCED DEFROSTING TIME ). The only necessary condition for the possibility to manually
activate defrosting is an external temperature drop below the threshold value specified in the EXTERIOR LIMIT TEMPERATURE
parameter
6.2.3
DEFROSTING DELTA
Defrosting delta is concerned with the difference of exterior temperature and the evaporator's temperature. This parameter
determines the threshold value. When exterior temperature falls below a certain value (Exterior limit temperature) and a specified
time of the heat pump operation elapses (blocked unfreezing time) the controller, based on the current delta value, starts the
defrosting process (if the threshold value is exceeded).
6.2.4
EXTERIOR LIMIT TEMPERATURE
This parameter determines the exterior temperature value below which the unfreezing procedure is activated.
6.2.5
UNFREEZING END TEMPERATURE
This parameter determines the evaporator's temperature value, which, when achieved, ends the unfreezing process. The
controller then returns to normal operation mode.
6.2.6
BLOCKED UNFREEZING TIME
The parameter determines the compressor operation time that must elapse to make it possible to activate the unfreezing process.
When exterior temperature falls below the limit value, the controller controls how long the compressor operates
– when the
blocked unfreezing time elapses, the controller passes on to the next unfreezing stage.
6.2.7
FORCED UNFREEZING TIME
This parameter determines the time after which the unfreezing process will be started regardless of the delta value. This time is
counted from the moment of switching the compressor on.
6.2.8
MAXIMUM UNFREEZING TIME
This parameter determines the maximum duration of the unfreezing process. After this time has elapsed, the unfreezing process
will be turned off regardless of the evaporator's temperature. In such a situation, the controller switches off all connected devices,
and the entire unfreezing process is resumed after the lapse of the compressor downtime.
MINIMUM OPERATION TEMPERATURE HYSTERESIS
Minimum working temperature hysteresis introduces a tolerance for the threshold activation temperature preventing undesirable
oscillations at small fluctuations in the activation temperature. It is the difference between the heat pump activation temperature
and deactivation temperature (after a temperature drop).
Example:
When minimum working temperature is set to 5
o
C, and hysteresis is set to 2
o
C, the heat pump will be activated at 5
o
C, however,
when the temperature outside begins to fall, then, after the temperature drops to 3
o
C, the pump will be turned off.
EXTERNAL TEMPERATURE WAITING TIME
The option sets the time after which the exterior temperature will be read.