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4. Protection Systems
4.1 Water flow switch
The heat pump is equipped with a flow switch to ensure that it does not run when the filter
pump is not working (and the water is not circulating).
This system prevents the heat pump from heating only the water present in the heat pump
itself. The protection also stops the heat pump if water circulation is cut off or stopped.
4.2 Refrigerant gas high and low-pressure protection
The high-pressure protection ensures that the heat pump is not damaged in case of over-
pressurisation of the gas. The low-pressure protection emits a signal when refrigerant is
escaping from the conduits and the unit cannot be kept running.
4.3 Overheating protection on the compressor
This protection protects the compressor from overheating.
4.4 Automatic defrost control
When the air is very humid and cold, ice may form on the evaporator. In such cases, a thin
layer of ice appears that will grow increasingly bigger as long as the heat pump is running.
When the temperature of the evaporator becomes too low, the automatic defrost control will be
activated: this will reverse the heat pump cycle so that hot refrigerant gas is sent through the
evaporator for a brief period of time to defrost it.
4.5 Temperature difference between in-flowing and out-flowing water
During normal operation of the heat pump, the temperature difference between the water
flowing into and out of the unit will be approximately 1 to 2°C. In the event that the pressure
switch does not work and that the water stops circulating, the temperature probe monitoring
the out-flowing water will always detect a rise in temperature. As soon as the temperature
difference between in-flowing and out-flowing water exceeds 13°C, the heat pump will be
automatically turned off.
4.6 Low temperature cut-off
If, during cooling, the temperature of the out-flowing water reaches or drops below 5°C, the
heat pump will turn itself off until the water temperature reaches or exceeds 7°C.
4.7 Anti-frost protection during winter
This protection can only be activated if the heat pump is in STANDBY.
4.8 First anti-frost protection
If the filter pump is controlled by the heat pump (regardless of the value set for parameter 9),
when the water temperature is between 2 and 4°C, and the air temperature is lower than 0°C,
the filter pump will be automatically turned on to prevent the water in the pipes from freezing.
This protection is deactivated when the temperature rises again.
4.9 Second anti-frost protection
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