7.2 Siting the outdoor unit
The outdoor units are painted with UV resistant paint.
Note
When the heat pump is installed in a corrosive atmosphere, the
ambient air and the air drawn in by the heat pump contain substan-
ces such as ammonia, sulphur, chloride, salts, etc. These substan-
ces can cause internal and external damage to the heat pump.
Viessmann heat pumps for outdoor installation are designed for
operation in moderately aggressive atmospheres. This makes them
suitable for installation in urban and industrial environments as well
as in coastal areas.
Higher corrosive loads can cause visual defects on the casing or
affect operation. The service life of the heat pump may be short-
ened.
Installation in coastal areas: Distance < 1000 m
In coastal areas salt and sand particles in the air increase the likeli-
hood of corrosion:
■ Site the heat pump where it is protected from direct onshore wind.
■ If necessary provide a wind break on site. Observe the minimum
clearances to the heat pump: See following chapters.
Requirements of the installation location
■ Select a site with good air circulation, so that the cooled air can
dissipate and be replenished by warm air.
■ Never install in the corners of rooms, in recesses or between
walls. This could result in an "air short circuit" between the air
being discharged and the air being drawn in.
■ When siting the unit where it is exposed to wind, ensure that the
wind cannot influence the fan area. This could result in an "air
short circuit" between the air being discharged and the air being
drawn in. Strong wind can have a negative influence on the evapo-
rator ventilation.
– An air short circuit in
heating mode
can result in reduced appli-
ance efficiency and defrosting problems.
– An "air short circuit" during
cooling mode
will result in the
heated, discharged air re-entering the unit. This can lead to high
pressure faults.
■ Select an installation location where the evaporator cannot be
blocked by leaves, snow, etc.
■ Select the installation site giving due consideration to the physical
laws concerning the propagation and reflection of sound: See
"Heat pump principles".
■ Never install next to or below bedroom windows.
■ Never install closer than 3 m to pathways, downpipes or sealed
surfaces. The cooled air in the discharge area creates a risk of ice
forming when outside temperatures are below 10 °C.
■ The installation site must be easily accessible, e.g. for mainte-
nance work.
Minimum clearances: See page 100.
Installation information
■ Floorstanding installation:
– Use supports for floorstanding installation (accessories): See
– Where such supports cannot be used, install the outdoor unit
freestanding on a solid base of at least 100 mm height.
– In difficult climatic conditions (temperatures below zero, snow,
humidity) install the appliance on a plinth of approx. 300 mm
height.
– Take account of the weight of the outdoor unit: See "Specifica-
tion".
■ Wall mounting:
– Use the bracket set for wall mounting (accessories): See
– The wall must meet the structural requirements.
■ Siting:
– Never install with the discharge side facing the main wind direc-
tion.
■ Weather influences:
– Observe wind loads when installing the unit on sites exposed to
the wind.
Where outdoor units are installed on a flat roof, considerable
wind loads may occur, depending on the relevant wind load zone
and height of the building. For such installation situations we rec-
ommend having the substructure sized by a design engineer in
accordance with DIN 1991-1-4.
– Provide thermal insulation of sufficient thickness on the pipework
to the outdoor air: See following table.
Pipework internal
7
Min. thickness of thermal insulation
layer with λ = 0.035 W/(m·K)
≤ 22 mm
40 mm
> 22 mm
60 mm
λ Thermal conductivity
– Incorporate the outdoor unit into the lightning protection system.
– Consider the heat emitted by the unit when planning your weath-
erproofing or an enclosure.
Design information
(cont.)
VITOCAL
VIESMANN
99
5831388
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