Minimum And Maximum Working Temperatures; Different Methods Of Heating Control; Defrosting Method - Worcester GREENSOURCE 6 kW Installation Manual

General

Minimum and maximum working temperatures

Maximum working temperatures
The heat pump can work with a maximum return temperature of approxi-
mately 59ºC. If the temperature rises above this value the heat pump will
stop for reasons of technical safety.
In the event of additional heat only, the maximum fl ow temperature is
limited to the factory setting 62ºC. This can be changed by the installer to
max 70ºC. If a value higher than 65ºC is set a mixing valve must be installed.
See Commissioning.
Minimum working temperatures
The heat pump stops if the outdoor temperatures falls below approx -20ºC.
All heat production then occurs in the HWDU by the additional electric
heater. The heat pump starts automatically when the outdoor temperature
climbs above approx -20ºC.

Different methods of heating control

The control unit uses different methods to control the heating installation.
These are: Control with an outdoor sensor and Control with an outdoor
sensor supplemented with a room sensor.
More information about the control methods can be found in the User
Guide.

Defrosting method

The principle of defrosting in the heat pump is known as hot gas defrost-
ing. During defrosting, the fl ow in the refrigerant circuit is reversed by
means of an electrically-controlled four-way valve. The compressed gas
from the compressor is fed into the top of the evaporator, causing the ice
on the outside to melt. During this process, the heating water is cooled
slightly. Hot gas is sprayed into the evaporator and sensor T11 ensures that
the process functions correctly. The time required for defrosting depends
on the amount of ice and the outdoor temperature.
This unit also operates as a fan defrost function, where hot air blows
upwards through the fan to prevent freezing.
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