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© STULZ S.p.A. – all rights reserved EN/06.2016/i09
WSA ExplOrEr OriginAl inStructiOnS
turned off
• keep the pump running for 8 hours and clean the implemented filter (recommended part of
the external circuit) after this lapse of time
7.2.3 commissioning of the refrigerant circuit
• Switch on the circuit breakers of the compressors.
• Adjust the desired set point of the water temperature in the controller
• Start the chiller unit by pressing the Start/Stop-key on the controller.
• Check after 20 minutes operation, whether gas bubbles are visible in the sight glass of the liq-
uid line. If this is the case, refrigerant might have escaped by a leak.
Check the circuit on leakages, eliminate them and fill the circuit with R134a in accordance to
the chapter “8 Maintenance” at page 73.
• Check the current consumption of the compressors comparing it with the values in the techni-
cal data.
• Check the oil level at compressors respects the right level. The oil sight glass is installed at the
compressor. The oil level should be between the lower quarter and the upper quarter of the
sight glass.
• Connect gauges at the high pressure and low pressure side and verify by reading the pres-
sures, that the saturation temperatures for evaporation (low pressure side) and condensation
(high pressure side), which correspond to the measured pressures, are within the following tol-
erances during the operation.
High pressure side
: max. 7 K above the water intake temperature of the condenser
low pressure side
: 3 to 7 K beneath the chilled water flow temperature
The pressure gauges feature a scale on the innermost ring indicating the saturation tempera-
tures belonging to the pressures.
Example:
Measured on the high pressure side: 13 bar (rel.) (= 14 bar abs.) corresponding saturation tem-
perature at the dew point according to scale for R134a: 52,5°C measured air intake tempera-
ture at the condenser: 35°C
t
cond
- t
air
= 52.5°c - 35°c = 17.5 K
ok
measured on the low pressure side: 2.5 bar (rel.) (= 3.5 bar abs.) corresponding saturation tem-
perature at the dew point according to scale for R134a: 5.0°C measured flow water temperature
at the evaporator outlet: 12°C
t
flow
- t
evap
= 12°c - 5,0°c = 7 K
ok
If the tolerances (18 K at the condenser, 7 K at the evaporator) are exceeded, there is a problem
of heat transmission. The probable cause is the pollution of the heat exchange surfaces. Also
the super-heating may be set too high.
