Danfoss DHP-AT, Installation Manual

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4.2.1 Accessories
The following accessories are available for the product:
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External electrical heater
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Circulation pump
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Reversing valve hot water
4.3 Principle function description
The heat pump can provide the following main functions:
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House heating
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Cooling
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Domestic Hot Water (DHW)
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Defrosting
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Legionella prevention
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Frost protection
To support these functions a suitable system solution, with the required components, is selected at installation. An example is shown in
the System Solution illustration.
By default, the heat pump operation is house heating/DHW AUTO which is the recommended configuration. This means that DHW is
prioritized before house heating or cooling. When the water tank temperature drops below the set point, the heat pump will switch to
DHW and heat the tap water until the temperature in the tank has reached its setting again. The unit will then switch back to house
heating or cooling.
The user can change the operation from AUTO to MANUAL mode and manually control some of the functions from the operator panel.
4.3.1 Operating heat pump in AUTO mode
House heating
In AUTO mode, the water temperature is adjusted by the control system according to the selected heat curve, the desired room temper-
ature, and the outside air temperature (if it is within the heat pump´s working range between -15°C to +43°C). The compressor stops
when the water temperature has reached the set point in the control system.
The heat pump has an internal electrical heater (3kW) for backup in situations where the compressor has stopped for other reasons.
According to the default settings in the control system, the internal electrical heater will start running in the following conditions:
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The control system discovers insufficient heating due to low outside air temperature (below -15°C).
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The heat pump stops working as a protective measure and at the same time, the water temperature has not reached its setpoint.
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The heat pump is defrosting.
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Freeze protection (step 2)
Start and stop conditions, internal electrical heater
The internal electrical heater will start in any of the following conditions:
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During defrosting cycle (assuming that the parameter value in Menu 13 is set to 1= turned on).
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During freeze protection (step 2)
Installation Guide DHP-AT
VMGFI302 Danfoss Heating Solutions
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