Auxiliary Heat; Important Parameters - Danfoss DHP-AX Installation And Service Instructions Manual

The heat pump unit consists of the following basic units:
1 Heat pump unit
C ompressor
z z z z
2 -way expansion valve
z z z z
C ondenser, stainless steel heat exchanger
z z z z
4 -way valve
z z z z
2 Fan
O ne speed
z z z z
3 Air heat exchanger Exchanger with copper pipes and
hydrophilic aluminium fins.
In addition to these units, there is control equipment (installed indoors),
which controls the heat pump unit's component parts (compressor, cir-
culation pumps, auxiliary heaters and exchange valve) and determines
when to start and stop the pump as well as whether to produce heat for
the house or hot water.
11.4

Auxiliary heat

Auxiliary heater is an option for DHP-AX and consists of an immersion heater,
which is located on the supply pipe ahead of the exchange valve.
The auxiliary heater, which is supplied as an accessory has an integrated power control and is controlled by a
potential free output from the heat pump. In the event of power cuts longer than three minutes, only a 6 kW
output may be connected immediately after power has returned, the remaining output is delayed two hours.
If the auxiliary heater is installed it engages AUTO mode automatically when the heat demand is greater than
the heat pump's capacity.
In the event of alarms that mean that the compressor does not start, hot water will not be produced in order
to indicate to the customer that something is wrong. Heat is produced by the auxiliary heater so that the
house does not become cold.
11.5

Important parameters

11.5.1 Heat production - calculating
The indoor temperature is adjusted by changing the heat pump's heat curve, which is the control system's tool
for calculating what the supply temperature should be for water that is sent out in the heating system. The
heat curve calculates the supply temperature depending on the outdoor temperature. The lower the outdoor
temperature, the higher the supply temperature. In other words, the supply temperature of the water fed to
the heating system will increase exponentially as the outside air temperature falls.
The heat curve will be adjusted in connection with installation. It must be adapted later on, however, to obtain
a pleasant indoor temperature in any weather conditions. A correctly set heat curve reduces maintenance and
saves energy.
11.5.2 CURVE
The control computer shows the value for CURVE by means of a graph in the character window. You can set
the heat curve by adjusting the CURVE value. The CURVE value indicates the supply temperature of the water
to be sent out to the heating system at an outdoor temperature of 0°C.
Value for CURVE is 40...
24 – Service
Supply temperature
Figure 19: Graph showing the set value 40 for CURVE.
...at zero degrees
VMBMH302
3
2
1
Figure 18: DHP-AX's main components.
Maximum supply tem-
perature
Outdoor temperature