Water Heat Exchanger Maintenance; Unit Maintenance; Refrigerant Volume - Riello NexPolar Series Installation And Technical Service Instructions

MAINTENANCE
5.5

Water heat exchanger maintenance

Check that:
— The insulating foam is intact and remains firmly in position.
— The BPHEs and the electric pipe heaters are functioning prop-
erly and are correctly positioned in a secure manner.
— The connections on the water side are clean and do not show
any signs of leaks.

5.6 Unit maintenance

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Prior to performing any intervention upon the unit, make sure
that the circuit has been isolated and that no electrical volt-
age is present. It should be noted that the circuit's condensers
could take up to 5 minutes to completely discharge after the
circuit has been isolated. Work upon the VFD must only be car-
ried out by qualified personnel.
In the event of an alarm or a persistent problem relating to the VFD,
contact the technical support service.
VFDs equipped with units do not require an isolation test, even if
they are replaced; in fact, they are systematically inspected prior to
delivery. Furthermore, the filtering components installed in the VFD
can distort the measurements and can also be damaged. If the iso-
lation of the device's components (fan and pump motors, cables,
etc.) needs to be verified, the VFD must be disconnected from the
power circuit.
5.7

Refrigerant volume

The unit must be activated in cooling mode in order to determine
whether the unit load is correct, by checking the actual subcooling.
A small refrigerant leak with respect to the initial load will be evi-
dent in cooling mode, and will affect the subcooling value obtained
at the output of the air heat exchanger (capacitor), but will not be
visible in heating mode.
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It is therefore not possible to optimize the refrigerant load in
heating mode following a leak. The unit must be activated in
cooling mode in order to determine whether an additional
load is required.
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