Description; General; Refrigerant Circuit (Heat Pump Operating Principle - Dimplex DHW 300D Installation And Operating Instructions Manual

tive). It is thus also intended for use by non-professionals for
heating shops, offices and other similar working environ-
ments, agricultural establishments and hotels, guesthouses
and other residential buildings.
ATTENTION!
Work on the domestic hot water heat pump is to be performed by
qualified personnel only!
Observe accident prevention regulations!
2

Description

2.1 General

The domestic hot water heat pump is a ready-to-use heating de-
vice whose main components are a domestic hot water cylinder,
the components of the refrigerant, air and water circuits and the
control, regulation and monitoring devices required for automatic
operation.
The domestic hot water heat pump is supplied with electrical en-
ergy and uses the heat stored in the intake air for domestic hot
water preparation. The optional internal heat exchanger can be
connected to additional heat generators such as boilers and
solar energy systems. The devices are equipped with an electric
flange heater (1.5 kW) as standard.
The temperature of the drawn-in air (the heat source) serves as
the reference value for the energy consumption, the domestic hot
water preparation heat-up time and domestic hot water tempera-
ture.
For this reason, an air duct system (DN 160, max. length 10 m)
can be connected to the standard spigot of the domestic hot
water heat pump for targeted waste heat recovery. For the heat
pump to be operated effectively, air short-circuits between the
drawn-in air and the blown-out air must always be avoided. This
can, for example, be achieved through the use of a bend on the
intake and outlet side.
Falling outlet air temperatures reduce the heat pump's heat out-
put and increase the heat-up time. In order for the heat pump to
be operated economically, the air intake temperature should not
fall below 15 °C for an extended period.
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The flange heater fulfils four functions:
 Supplementary heating
The heat-up time is approximately halved by switching on
the flange heater in addition to the heat pump.
 Frost protection
If the air intake temperature falls below -7 ±1.0 °C, the
flange heater switches on automatically and (nominally)
heats the water up to the domestic hot water set tempera-
ture.
 Emergency heating
In the event of a heat pump fault, the domestic hot water
supply is maintained by the flange heater.
 Preventative thermal disinfection
Using the operator panel keypad, domestic hot water tem-
peratures above 60 °C (up to 65 °C) can be programmed via
the "preventative thermal disinfection" menu. These temper-
atures are achieved through the flange heater above 60 °C.
NOTE
When the domestic hot water temperature reaches > 60 °C, the heat
pump switches off and the domestic hot water preparation is heated
solely by the flange heater. The factory setting for the heating element
controller is 65 °C.
2.2 Refrigerant circuit (heat pump
operating principle)
The refrigerant circuit is a closed system in which the R134a re-
frigerant is the work material. The finned heat exchanger extracts
heat from the drawn-in air at a low evaporation temperature, and
transfers it to the refrigerant. The vaporous refrigerant is taken in
by a compressor, where it is compressed to a higher pressure
and temperature level before being transported to the liquefier,
where the heat absorbed in the evaporator and part of the com-
pressing energy is transferred to the water. Subsequently, the
high condensation pressure is lowered to the evaporation pres-
sure by a throttle mechanism (expansion valve), and the refriger-
ant can again extract heat from the intake air in the evaporator.
451905.66.02 · FD 9506
DHW 300D - DHW 300D+
EN-3