64
EN/06.2016/i01 © STULZ S.p.A. – all rights reserved
WPA ExPlOrEr OrIGINAl INSTrUCTIONS
WArNING
All power switches are already set or adjusted by the manufacturer. Do not turn the
adjustment screw.
• Switch on the control-circuit fuses and the power switches of the condenser fans in sequence.
The compressor power switches may not be switched on, yet.
• Switch on the chiller unit at the master switch
The crankcase heater and the controller are now supplied with power, so you can use it for
adjustments.
7.2.1 Oil preheating
To preheat the oil, the chiller must be supplied with voltage, the circuit breakers of the compres-
sors must be switched off for safety reasons. In normal operation of the chiller, the oil heater
is always in operation when the compressor is switched off. The control (Start/Stop key on the
controller) should also remain switched off during the oil preheating.
According to the specification of the compressor manufacturer the oil must have a minimum
temperature of 20°C and be at least 20 K above the outdoor temperature. Above an outside
temperature of 10°C the oil preheating should be launched 8 hours before the first start of the
compressor. Below an outside temperature of 10°C, the chiller requires an oil preheating time of
24 hours. During the oil preheating time the compressor cabinet should be kept closed.
7.2.2 Commissioning of the chilled water circuit
WArNING
Ensure that the water system has been sufficiently filled and that all stop valves are open.
With external pump
:
• check the sense of rotation and start the pump
• check that the water flow guaranteed by the pump respect the nominal flow rate indicated in
the data sheet of the chiller
• check that the inlet-outlet temperature difference (ΔT) is between 4 and 8K (with all the com-
pressors running at the maximum power)
• check the correct functionality of the differential pressure switch or the flow switch (option)
turning off the pump and check if the chiller is 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
With internal pump
:
• check at the pressure gauge that the pressure delivered by the pump is aligned to the data
sheet of the chiller and the pump is working within its performance curve limits
• check the correct functionality of the differential pressure switch or the flow switch (option)
turning off the pump (use the contactor in the electrical cabinet) and checking if the chiller is
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
