69
© STULZ S.p.A. – all rights reserved EN/06.2016/i01
WPA ExPlOrEr OrIGINAl INSTrUCTIONS
8.3.2 Quantity
To be checked: charge of refrigerant
An overfilling of the circuit makes the condensation pressure rise and by that the power con-
sumption of the compressor. In the extreme the HP-switch triggers.
8.3.3 Tightness of refrigerant circuit
To be checked: pipes, connections, valves
According to article 3 of the EC regulation No. 842/2006 the operator must check the refriger-
ant circuit of the chiller every 6 months for leaks. In the chillers described here, no more than
200 kg (2 x 100 kg) refrigerant R410A are used.
After repairing a leak, the refrigeration circuit must be checked on tightness within one month.
The following information must be recorded by the operator in writing:
• quantity and type of the used refrigerant
• refilled refrigerant quantity
• recycled refrigerant quantity
• companies or persons which have carried out maintenance
• dates and results of inspections
8.3.4 Purity
To be checked: sight glass, filter drier
At full cooling capacity, 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 or purple to blue
ok
• Yellow or rose to red
humidity critical
With too much humidity in the circuit, the expansion valve can freeze. In addition to this the ester
oil in the compressor, which comes in touch with the refrigerant, takes up humidity and loses its
ability to lubricate.
Take an oil sample, determine the humidity content and exchange the oil in
case of excessive humidity content.
In this case the refrigerant must be completely evacuated and recharged by
new refrigerant according to the above described instruction.
