A2.5.3 Re-adjustment of oil pressure regulator (re-
fer to fig. A2.1)
Re-adjustment procedure:
a) Run the compressor for 15 minutes until the
crankcase oil is at its stable operating temperature [Toil].
b) Determine the oil pressure difference (difference
between the pressure gauges of the oil and suction
or [dOil]).
c) After approx. 15 minutes of operatinf and an oil
temperature of 50 °C, the oil pressure difference
should be approx. 2.0-2.5 bar.
During these first minutes the pressure should be
slightly higher.
d) Remove the cap nut (3) with alu ring (2), of the oil
pressure regulator if the pressure needs to be
re-adjusted.
e) Turn the slotted pin (1) with a screwdriver clockwise
or counter clockwise for a higher or lower oil
pressure respectively, until the required oil pressure
differences has been achieved.
f) Replace the cap nut (3) with alu ring (2).
Settings of compulsory pressure safeties
Read-out
Monitron
1
)
Description Min. value Max. value (pre)-Setting
Psuc Suction pressure 0.3 bar (4.4 psia) NH3 6.2 bar (90 Psia)
R22 6.8 bar (99 Psia)
R134a 6.2 bar (90 Psia)
R404A 6.0 bar (87 Psia)
R507 5.8 bar (84 Psia)
5 °C (9 °F) below design
evaporating temperature
Pdis Discharge pressure > Psuc 26.0 bar (377 Psia) 5 °C (9 °F) above design
condensing temperature
Pdis-Psuc > 0 bar 24.0 bar (348 Psia) < 24.0 bar (348 Psia)
dPoil Lubrication oil
pressure difference
1.5 bar (22 Psia) 2.5 bar (36 Psia) The oil pressure
regulator is adjusted at
the works, but it may
occur that this setting
should be corrected
during the initial run
(see A2.5.3)
1
)In case of Monitron the values are measured via pressure transducers, otherwise protection via switches is compulsory.
Fig. A2.1 Oil pressure regulator
1 slotted pin
2 alu ring
3 cap nut
4 return from oil separator
or oil rectifier
5 oil pressure regulator
Refrigeration Division
Grasso
A: INSTALLATION AND PREPARATIONS FOR USE
v001.99.01.en Installation and Maintenance Manual RC(U)6 A2.3
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