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EN/05.2019 © STULZ GmbH – all rights reserved
CYBERHANDLER 2 INSTALLATION, OPERATION AND MAINTENANCE MANUAL
Quantity
– Check the
HP switch
An overfilling of the circuit makes the condensation pressure rise and by that the power
consumption of the compressor. In the extreme the HP-switch triggers.
Purity
– Check the
sight glass
and the
filter drier
.
Bubbles in the sight glass indicate that the charge is insufficient or that the filter drier is
clogged.
A pollution of the filter drier, whose origin task is to clear the refrigerant from impurities and
humidity, can be detected by a temperature difference upstream and downstream the filter
drier.
Compare the colour indicator in the centre of the sight glass with the outer ring scale.
green → ok.
yellow → humidity critical.
With too much humidity in the circuit, the expansion valve
can freeze. In addition to this the ester oil in the compres-
sor, which comes in touch with the refrigerant, takes up
humidity and loses its ability to lubricate.
In this case the refrigerant must be completely evacuated
and recharged according to the above described evacua-
tion instruction.
Sight glass
Compressor
In the compressor there is an ester oil charge, which does not have to be renewed under normal
operation conditions and holds out for the unit’s lifetime. However, it is possible that the ester
oil, as it reacts hygroscopically, has taken up humidity of the air after repeated recharging of
the refrigerant circuit due to repair works. The interaction between ester oil and water results
in the formation of acid. Owing to a hyperacidity, corrosive processes take place inside the
compressor. In this case the ester oil should be exchanged.
The oil level can be checked by looking at the sight glass of the compressor.
Units with a speed controlled compressor are not equipped with an oil sight glass. For
these units it is not allowed to recharge oil in case of refilling a refrigeration circuit
after a leakage. In such cases the compressor has to be exchanged.
