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EN/06.2016/i09 © STULZ S.p.A. – all rights reserved
WSA ExplOrEr OriginAl inStructiOnS
6.3 refrigerant circuit
As a protection against over pressure the refrigerant circuit is equipped with a safety valve on
the pressure side of the compressor.
When attaching any pipework to a relief valve the pipes must be of a sufficient diameter so as
not to cause resistance to the operation of the valve. For critical or complex installations refer to
EN 378, unless it is not specified by local regulations, the internal diameter can be calculated
using the following formula:
D
5
= 1.447
x
l
D
: Minimum pipe internal diameter in centimetres
l
: Length of pipe in meters
6.4 External water circuit
The evaporator water circuit of the chiller contains an evaporator, a differential pressure switch,
temperature sensors in the inlet and outlet, a pressure gauge and vent valves.
For a detailed overview, please take a look at the circuit diagram in chapter “4.5 Hydraulic dia-
grams” at page 31.
On the evaporator side a frost protection sensor measures the temperature of the liquid and
reports it to the controller in which a threshold for an antifreeze alarm is defined. This value is
adjusted on 4°C in the factory. Below this water inlet temperature it releases a frost protection
management by the controller, which may lead to an antifreeze alarm. The adjusted value of 4°C
can be modified and has to be adapted to the local conditions (glycol content).
If the water temperature passes under 5°C or if the outside temperature is less than 2.5°C, we
recommend to add the following quantities of Ethylen glycol (indicated as percentage of weight
of the water quantity):
Ethylenic glycol
External temp.
%
from +5 to -5°C
10
from -5 to -10°C
20
from -10 to -15°C
28
from -15 to -20°C
35
from -20 to -25°C
40
inFOrMAtiOn
Establish the required water/glycol mixture outside of the chilled water circuit and fill the
circuit later.
WArning
Do not add any other fluids or additives to the filling liquid except those provided. Do not
mix any products and/or additives of different brands
