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© STULZ S.p.A. – all rights reserved EN/06.2016/i09
WSA ExplOrEr OriginAl inStructiOnS
inFOrMAtiOn
R134a must be charged in a liquid state.
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 increases. In the extreme case 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 refrig-
erant circuit of the chiller every 6 months for leaks. In the chillers described here, no more than
400 kg (2 x 200 kg) refrigerant R134a 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
Bubbles in the sight glass indicate that the charge is unsufficient 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 addi-
tion to this the compressor oil, 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 evacuation instruction.
8.3.5 Exchange of filter drier
To be checked: filter drier, shut-off valve RU1-RG2
