Technical data
18 | Project planning manual for heat pumps for heating and domestic hot water preparation | 01.2012 www.dimplex.de
2 Air-to-water heat pumps
2 Air-to-water heat pumps
2.1 Air as heat source
Area of application of air-to-water heat pumps
General information on the operating limits of air-to-water heat
pumps is not possible. The operating limits may differ due to dif-
ferent components in the heat pump or different refrigerants.
Areas of application include:
LA ..TAS of -25 °C to +35 °C
LIA ..IM of -20 °C to +35 °C
NOTE
The operating limits of the different heat pumps can be found in the de-
vice information in the attachment.
Availability of outside air as a heat source
Unlimited
Types of operation
Mono energy
Bivalent-parallel (partial-parallel)
Alternative bivalent mode
Bivalent-renewable
Buffer tank
The integration of an air-to-water heat pump requires a buffer
tank connected in series to ensure that the evaporator (finned
heat exchanger) is defrosted by means of reverse circulation. In-
stallation of a buffer tank connected in series also lengthens the
runtimes of the heat pump during periods of reduced heating de-
mand (see Chapt. 8.6 on page 103).
Condensate drain
Condensate that forms during operation must be drained off
frost-free. To ensure proper drainage, the heat pump must be
mounted horizontally. The condensate pipe must have a mini-
mum diameter of 50 mm and must be fed into a sewer in such a
way that it is safe from frost. If the condensate is to be fed into
sewers where sewer gases may occur, the evaporator must be
protected from sewer gases with a siphon. Defrosting takes
place up to 16 times per day, with up to 10 litres of condensate
being produced each time (see Fig. 2.1 on page 18).
Fig. 2.1: Foundation plan heat pump with condensate drain
NOTE
The frost line can vary according to the climatic region. The regulations
of the countries in question must be observed.
ATTENTION!
If the condensation is fed into clearing tanks and sewage systems, a
siphon is required in order to protect the evaporator from damaging
vapours.
ATTENTION!
The district heating line must be laid so that no water can enter the line
via the foundation of the outdoor unit. To this end, the district heating line
must be fed approx. 2 - 3 cm out of the foundation.
Recommended Installation
The air-to-water heat pump should preferably be installed out-
doors. This is a simple, economical installation option because
the requirements placed on the foundations are minimal and this
set-up avoids the need for air ducts. Installation is to be done in
compliance with the regulations set down in the relevant federal
building codes. If outdoor installation is not possible, it should be
kept in mind that condensation can form on the heat pump, on air
ducts and especially around wall openings when the heat pump
is installed in rooms with high humidity.
Frost protection
The heat circulating pump is activated automatically and as re-
quired by an integrated frost protection sensor to prevent the
heat pump from freezing when it is not in service (Chapt. 8.2 on
page 94).
ATTENTION!
The intake air must not contain ammonia. The use of exhaust air from
animal stables is therefore not permitted.
Maintenance information
To guarantee safe operation of the heat pump, maintenance
work must be carried out on the pump at regular intervals. The
following work can be carried out with no special training:
Cleaning the ribs on the evaporator
Cleaning inside the heat pump
Cleaning the condensate tray / condensate drain
Cleaning the air ducts (air inlet and outlet)
The heat pump must also be checked for leaks and the function
of the refrigerant circuit checked at regular intervals.
NOTE
Further information of country-specific standards relating to leakage
tightness tests on heat pumps is available at www.dimplex.de/dichtheits-
pruefung.
ATTENTION!
Work on components carrying refrigerant may only be carried out by a
trained cooling technology specialist.
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