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© STULZ S.p.A. – all rights reserved EN/06.2016/i09
WSA ExplOrEr OriginAl inStructiOnS
4.2 intended use
This chiller is intended for the chilled water production and for the chilled water control. TThe
chiller is designed for outdoor installation on the roof of a building or at the ground level. Any
use beyond this is not intended. STULZ is not liable for any damage resulting from such misuse.
The operator alone bears the risk. The chiller must not be used for the warming of water.
4.3 chiller Design
4.3.1 general
The chillers of the Explorer WSA series with screw compressors exist in 5 construction sizes
which differ by their dimensions and cooling capacity. The chiller consists of two separate refrig-
erant circuits with one semi-hermetic screw compressors in each circuit, a single shell & tube
evaporator, air cooled condensers and an electronic expansion valves in each refrigerant circuit.
After assembling the chiller each unit is pressure tested, evacuated and fully factory charged
with R134a and oil in each of the independent refrigerant circuits. The end of line test also
includes an operational test with water flowing through the evaporator to ensure that each
refrigerant circuit operates correctly.
4.3.2 Versions
The standard version for water cooled chillers with screw compressors has a unit designation
which takes the following pattern: WSA _ _ _ 2 CN _ . There is one more version which will be
described in the following.
Free cooling Version
The free cooling version is available for all the sizes. This Version additionally contains free cool-
ing coils positioned directly in front of the condensers and therefore in W-shape. .
During free cooling mode two motor-driven 2-way-valve directs the water volume completely
through the free cooling coils.
low noise version
With the low noise version of the Explorer WSA chillers you have the possibility to reduce the
noise emissions to up to –10dB.
There are two main sources which are responsible for the noise. One is the fan section and the
other one is the compressors. To reduce the noise caused by the fans the fan speed of the low
noise version is reduced by changing the electrical connections from delta to star. This occurs in
a reduction of the fan speed of approx. 30%.
To reduce the noise emitted by the compressors they are installed in a completely insulated
compressor compartment.
4.3.3 refrigerant circuit
Two independent refrigerant circuits are provided. Each circuit uses copper refrigerant pipes that
are formed on computer controlled bending machines where possible to reduce the number of
single point of failures and to provide a reliable and leak resistant system.
An electronic expansion valve is also a part of the standard equipment as well as a filter dryer
