A2.6 Checking direction of rotation of motor shaft
Prior to installing the intermediate coupling element
or V-belts, the direction of rotation of the motor
shaft must be checked either by bumping the
electrical drive motor or by measuring the rotation
of the field (direction of rotation normally counter
clockwise when facing compressor shaft end).
A2.7 Installing the (drive) guards (if present)
Only after the compressor is ready for the initial
startup! Refer to the drive guard installing
procedures included in the order documentation.
A2.8 Initial oil warm up
Prior to the initial start-up (refer to §A2.9), the
crankcase heater (if present) must be energized. For
the min. oil temperature (min. [Toil]) refer to page VII.
A2.9 Initial start-up
A2.9.1 Limitations of part load operation and
start-up
The capacity control serves to adapt the compressor
capacity at any moment as closely as possible to the
refrigerating capacity. In order to adapt the capacity,
a number of cylinders can be put in or out of action
either individually or collectively.
Due to start-up limitations and to
limitations of part load operation it may
be that not all available part load steps
are allowed under certain conditions.
Use of incorrect control steps can
damage compressor and/or components.
In the case of a Monitron Controller, all these
limitations will be checked automatically.
For a detailed description about these start-up
and part load limitations refer to the "Engineering
Data".
A2.9.2 Pre-start check list
The following Paragraph covers only the initial
start of the compressor and not the complete
refrigeration plant.
Be sure that all necessary system valves are open
and that the refrigeration system is ready for start
up. Use the following check to guarantee that no
items of importance regarding the compressor
(package) have been overlooked.
a) System is charged with refrigerant.
b) Monitron (if present) is properly installed (refer to
the Monitron Instruction Manual).
c) Settings of safety limit switches are adjusted properly.
d) Direction of rotation of compressor crankshaft is
correct.
e) Oil level established in sight glass.
f) Stop valves to the pressure gauges are open (if
present).
g) Suction stop valve is closed (in case the evaporating
temperature is much higher than the design
evaporating temperature) and the discharge stop
valve is open.
h) Stop valve in the oil return line of the oil separator
(if present) is closed.
When all items a) through h) are verified, the
compressor (package) is ready for the start-up.
A2.10 Starting and stopping procedures
When starting the compressor a distinction should
be made between:
A2.10.1 Starting for the very first time (between
brackets [ ] are Monitron units)
a) Notice §A2.9.2 "Pre-start check list", consult also the
plant manual and verify the following items:
- Check the oil temperature [Toil] (refer to the
"Engineering Data").
- Check crankcase oil level (refer to §B4.1).
b) Start the compressor and check whether the oil
pressure [Poil] increases.
Maximum 6 starts per hour and at least 2
minutes between stopping and starting
and at least 10 minutes between starting
and re-starting
Refrigeration Division
Grasso
A : I N S T A L L A T I O N A N D P R E P A R A T I O N S F O R U S E
A2.4
Installation and Maintenance Manual RC(U)6
v001.99.01.en
