B3 STEPS FOR LONGER SHUT-DOWN PERIODS
(> 6 months)
To shut down a compressor for long term periods,
proceed as follows:
a) Tightly shut both the suction and discharge stop
valves and the stop valve of the oil return line (if
present).
b) Disconnect the power source from the compressor
drive motor and the electrical control cabinet of the
Monitron CR (if present).
c) Place a moisture absorbing compound (eg a
dessicant such as silica gel) inside the control cabinet.
d) Place warning tags on the electric system and all
closed stop valves.
Prior to starting up after a shut down, change the oil
(refer to §B6) and clean or exchange the oil filters (refer
to §B7). Determine the starting and stopping
procedure from §A2.10 prior to start the compressor.
B4 LUBRICATION DATA
Determine max Toil and set this value in the safety
device (Monitron CR, if present).
Change the oil as soon as an oil analysis (refer to
§B2.2 for frequency) indicates contaminated oil.
It is expressly pointed out that it is not
permitted to mix different types of oil. If
another type of oil is used, first remove
all the stale oil in the filters, oil pump,
crankcase, shaft seal, oil separator and
oil drains of the installation.
B4.1 Topping up oil with compressor operating
Topping up oil is permitted during compressor
operation.
Be sure that this oil is the same as in the plant
(refer to §B4).
Without affecting the operation of the compressor,
the oil may be topped up by means of a separate oil
pump. This pump enables the oil to be forced into the
crankcase via the oil charging valve, against suction
pressure. If this oil pump is not available, oil can be
charged by reducing the crankcase pressure to below
atmospheric pressure.
The procedure is as follows:
a) Connect a hose to the oil charging valve after
removing the cap nut.
b) Fill the hose with oil and immerse its loose end in a
reservoir containing sufficient oil.
c) Close the suction stop valve so, that the suction
pressure falls below the atmospheric pressure.
d) Keep the oil charge valve open as long as the oil in
the crankcase has attained the required level again.
Take care that no air is being drawn into the
crankcase.
e) Slowly open the suction stop valve to avoid liquid
hammer which may damage the compressor.
f) Remove the hose and replace the cap nut with
gasket onto the oil charging valve.
Fig. B1 Oil level in compressor sight glass
Refrigeration Division
Grasso
B: INSPECTION, MAINTENANCE
AND TROUBLE SHOOTING
B1.4
Installation and Maintenance Manual RC(U)6
v001.99.01.en
