Installation manual

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Air-to-Water Heat Pumps 2.2.1
2 Air-to-Water Heat Pumps
2.1 The Air as Heat Source
Area of application of air-to-water heat pumps
-25 °C... + 35 °C
Availability of outside air as a heat source
 Unlimited
Types of operation
 Mono energy
 Bivalent-parallel (partial-parallel)
 Alternative bivalent mode
 Bivalent-renewable mode
Buffer tank
The integration of the 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.
Installation of a buffer tank connected in series also lengthens
the runtimes of the heat pump during periods of reduced heating
demand (see Chap. 8.5 on p. 180).
Condensate outflow
Condensed water that forms during operation must be drained
off frost-free. The heat pump must be mounted on a level plane
to guarantee proper drainage. The condensed water pipe must
have a minimum diameter of 50 mm and should be fed into the
sewer for rain water to ensure that large quantities of water can
be drained off. Defrosting takes place up to 16 times daily, with
up to 3 litres of condensed water being produced each time.
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.
Recommended Installation
The air-to-water heat pump should preferably be installed
outdoors. 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 ducting. 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.
ATTENTION!
The intake air must not contain ammonia. The use of air from animal
stables is therefore not permitted.
2.2 Air-to-Water Heat Pumps for Indoor Installation
Costs for indoor installation
 Air circuit (e.g. ducting)
 Wall openings
 Condensate outflow
General information
An air-to-water heat pump should not be installed in the living
quarters of a building. In extreme circumstances, outside air as
cold as -25 °C may pass through the heat pump. This can lead to
the formation of condensation in the area around wall openings
and air duct connections in rooms with high humidity, e.g.
kitchens and laundry rooms, eventually resulting in damage to
the building. The formation of condensation cannot be avoided
(evenwith good thermal insulation) if the ambientair humidity
exceeds 50 % and the external temperature is below 0 °C.
Therefore, unheated rooms such as cellars, storerooms, and
garages are more suitable installation locations.
NOTE
For a higher degree of sound protection, the air outlet should be over a
90° bend or outdoor installation should (Chap. 2.4 on p. 24) be selected.
If the heat pump is installed on an upper storey, the load-bearing
capacity of the ceiling should be checked. Installation on a
wooden floor is not recommended.
NOTE
If the heat pump is installed above inhabited rooms, constructional
measures for solid-borne sound insulation are required.
Air circuit
Air-to-water heat pumps installed indoors must be supplied with
a sufficient air volume flow to ensure efficient and smooth
operation. This is based primarily on the heat output of the heat
pump and is between 2,500 and 9,000m
3
/h (see Chap. 2.6 on p.
28). The minimum dimensions for the air ducting must be
observed.
Air circulation from the air intake through the heat pump to the air
outlet should be as unhindered as possible so that any
unnecessary air resistance is avoided (Chap. 2.3 on p. 21).
2.2.1 Requirements placed on the installation location
Ventilation
The room in which the heat pump is installed should preferably
be ventilated with outside air so that the relative humidity level
remains low and the formation of condensate is avoided.
Condensate can form on cold components in particular during
start-up of the system and when the building is being dried out.
ATTENTION!
The heat pump must not be operated without appropriate air circulation
because of the risk of injury caused by rotating parts (ventilator).