Unit installation

Use and Maintenance Manual Air-cooled water chillers and Heat Pumps R-PAE/R-PAH/EAH Rev. 1 del 03/09
Picture 39
4.6.5 Phases sequence in the power supply line
The rotation direction of all electric motors installed on the unit (compressors, fans, pumps) are checked and
harmonized during the operational test performed by the manufacturer (at the exception of units supplied with
arrangements for special power supply tension). In case of three-phase power supply, when connecting the unit to
the power supply, it is necessary to check that the phases are connected in the correct sequence. On this purpose,
make sure that all electric motors rotation is right: for pumps and fans, refer to the information indicated on the
component itself; for scroll compressors, follow the instructions as described at Par. 5.1.
If the rotation of any component is wrong, two out of three phases must be inverted in the terminals of the main
switch (do not unplug the neutral). If some components go on rotating in the wrong direction, check the conductors
sequence of each 3-phase component and correct it, if needed.
4.6.6 Application
The nominal water flow capacity refers to a temperature difference of 5°C between the inlet and outlet depending on
the supplied cooling capacity. The maximum allowed capacity is equal to 1,2 times the above mentioned value
(higher flow rates could cause noise and vibrations with consequent damage to the evaporator).
The minimum allowed flow capacity is equal to 0,8 times the nominal value (lower flow rates might cause a too low
outet water temperature thus involving the safety device activation and the unit stop).
WORKING LIMITS
Unit Water temperature Air temperature
Water chiller min evaporator outlet H
2
O Temp = 5° C
(4)
max evaporator inlet H
2
O Temp = 20° C
ext. Air Temp: varies between +15 and
+40° C
(1)
Heat pump min condenser inlet H
2
O Temp = 25° C
(2)
max condenser outlet H
2
O Temp = 50° C
(3)
There are no special limits, but the
operation with low T° (below 0°)
reduces significantly the unit
performance.
tab. 10
(1) for different applications, contact the Customer Service
(2) lower temperatures can cause unit malfunctioning
(3) higher temperatures can enable the safety device and stop the unit
(4) if the unit works with water temperatures lower than 5°C (on the evaporator outlet), besides using a water/ethylene
glycol mixture, it is necessary to reset the anti-freeze thermostat (always 4° C above the mixture freezing point) and the
set-point according to the desired temperature and to the temperature difference to the evaporator.
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