EU heat pumps
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5. Protection systems
EU heat pumps are equipped with the following standard protection systems:
5.1 Water pressure switch
Thanks to this pressure switch, the heat pump will not work 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.
5.2 Refrigerant gas high and low pressure protection
The high pressure protection makes sure the heat pump is not damaged in case of overpressurisation of the gas.
The low pressure protection emits a signal when refrigerant is escaping from the conduits and the unit cannot be
kept running.
5.3 Overheating protection on the compressor
This protection protects the compressor from overheating.
5.4 Automatic defrost control
When the air is very humid and cold, ice can form on the evaporator. In that event, 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
has become too low, automatic defrost control will be activated, which will reverse the heat pump cycle so that
hot refrigerant gas is sent through the evaporator during a brief period of time to defrost it.
5.5 Temperature difference between inflowing and outflowing water
During normal operation of the heat pump, the temperature difference between inflowing and outflowing water
will approximate 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 outflowing water will always detect a rise in temperature. As
soon as the temperature difference between inflowing and outflowing water exceeds 13 °C, the heat pump will
be automatically turned off.
5.6 Low temperature cut-out
If, during cooling, the temperature of the outflowing water reaches 5 °C or drops below this temperature, the
heat pump will turn itself off until the water temperature reaches or exceeds 7 °C again.
