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© STULZ GmbH – all rights reserved EN/09.2019/G41
cybercool 2 screw original insTrUcTions
Screw compressor
In the screw compressor, there are three components which require inspection and maintenance. 1. the pres
-
sure relief valve, 2. the check valve, 3. the roller bearing. The integrated oil filter is maintenance-free.
1. Pressure relief valve
The pressure relief valve has a response pressure difference of 28 bar and is maintenance-free. Repeated
opening of the valve due to abnormal operating conditions, however, may result in steady leakage. This can be
detected by a reduced output and a high discharge gas temperature. If this the case, replace the valve.
2. Check valve
To protect the compressor against reverse rotation during standstill, a check valve is installed under the dis
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charge shut-off valve resp. below the pipe connection. If the compressor runs in reverse direction for more
than aproximately 5 sec. after the cut-off, the valve may be defective and must be replaced. A reverse rotation
of the compressor can be detected by an abnormal sound.
3. Roller bearing
The screw compressors are equipped with fatigue endurable roller bearings. The bearings can be checked
by means of a sound analysis. If the bearings must be replaced, also the rotors, the housing and the discharge
flange should be checked visuallly. In case of severe scores or abnormal abrasion, a major overhaul of the
compressor or its replacement is advisable .
(2) oil service valve
(1) oil drain plug
(3) oil sight glass
oil heater
hot gas line connection
suction line connection
Screw compressor, sectional view
Component
Inspection intervall
Replacement intervall
Pressure relief valve
h
only if damage is suspected
100.000
Check valve
h
5.000*
20.000 ... 40.000
Roller bearing
h
10.000
50.000
*at least yearly check
