Screw Compressor Packages Without Refrigerant Injection; Compressor Units With Refrigerant Injection; Start-Up After Long Standstill Periods; Restarting After Approx. 1 Year Standstill - GEA Grasso M-Series Operating Manual

Start-up
8.5.17.1 Screw compressor packages
without refrigerant injection
The amount of injection oil and the oil temperature
directly influence the discharge temperature of the
compressor. The amount of injection oil is adjusted
under operating conditions through the injection oil
control valve.
Standard values for discharge temperature
t
NH /HP t ≥ t + 20K 30K
3 oil
NH /LP t ≥ t approx. 45 ... 60°C
3 oil
Freon/HD t ≥ t + 15K
oil
R22/LP t ≥ 45 ... 60°C
8.5.17.2 Compressor units with refriger-
ant injection
The oil temperature is changed by setting the injec-
tion oil control valve. The more the shut-off valve is
throttled, the more the oil temperature decreases. If
the oil temperature becomes too low or reaches the
lower range, the setpoint for the discharge tempera-
ture should be set higher accordingly. In the first set-
ting of the oil circuit, the control valve for injection oil
is opened approximately half a turn.
The discharge temperature is then regulated to the
value indicated in the parameter list by means of the
thermostatic expansion valve.
Guide value for compressor end temperature: t
= 60 + 10°C (for NH )
3
Other refrigerants on request.
8.6

Start-up after long standstill periods

1. Inserting the main fuse
2. Switching on the control unit according to the
operating manual.
3. Checking all parameters on the control unit dis-
play. See parameter list.
4. Checking the settings of all control and safety
devices.
64
8.7
•
Change the oil filter inserts (see maintenance
instruction).
•
Switch on the oil heater at least one hour before
starting the screw compressor package/chiller.
•
Open the stop valve on the suction side and the
pressure side (or check valves which can be
shut off).
t
•
max If fitted: Open the stop valves (or shuttable check
valves) in the suction line of the economiser.
95°C
•
If fitted: Open the refrigerant supply to the ther-
mosyphon - oil cooler.
80°C
•
If fitted: Open the manual stop valve of the refrig-
erant injection.
80°C
•
Remove all non-condensable gases by venting.
To this end, check the condensing pressure and
80°C
temperature (see parameter list).
•
Check the oil collection sump and drain if neces-
sary.
•
Switch on the compressor and observe the oper-
ating instructions of the electrical switchgear.
Make a screw compressor package/chiller test
run in order to test the sensor and actor technol-
ogies (for operation and indicating precision).
e
GEA Refrigeration Germany GmbH | P_261511_1 | Generated 01.04.2015
Operating Manual | GEA Grasso M-Series
Screw Compressor Packages
Restarting after approx. 1 year
standstill