User manual

transferring heat to the refrigerant circuit, which is then given off in the
air heat exchanger.
If the hot water heater is installed the control unit will alternate
between cooling and hot water production with prioritisation for the
hot water requirement.
3.1.7 Speed controlled fan
The fan starts at a nominal speed, which differs depending on the size of
output. The fan speed is adjusted up or down as required which is
determined by the temperatures in the refrigerant circuit.
3.1.8 Electronic expansion valve
When the refrigerant passes the expansion valve the pressure and tem-
perature of the refrigerant are reduced. In this way the energy in the
outdoor air is available to the refrigerant circuit. By regulating the open-
ing degree of the expansion valve one can optimise the flow in the
refrigerant circuit in different operating conditions. Control of the elec-
tronic expansion valve is based on the measurements of temperatures
and pressures in the refrigerant circuit and outside air.
3.1.9 Auxiliary heat
The auxiliary heater is included in DHP-AQ Midi and DHP-AQ Maxi and is
available as an accessory for DHP-AQ Mini. An auxiliary heater consists
of an immersion heater, which is located on the supply pipe ahead of
the reversing valve.
If the auxiliary heater is installed it engages AUTO mode automatically
when the heat demand is greater than the heat pump’s capacity.
Immersion heaters in DHP-AQ series intended for 400V voltage supply
have three heating elements (AUX. HEAT 1, 2 and 3) and can be control-
led in five power stages. Products for 230V have two heating elements
(AUX. HEAT 1 and 2) and are controlled in three power stages. The two
stages 4 and 5 cannot be engaged when the compressor is in operation
as opposed to stages +4 and +5 where it is possible.
230V 400V
Step 1 3 3
Step 2 6 6
Step 3 9 9
Step 4 12
10 – User manual VUGFB102