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Installation information
4.3.3
Foundation
To obtain the desired vibration damping, the concrete foundation must have the necessary bear-
ing strength and be as plane as possible. Always collect weight information of the chiller unit be-
fore projecting the concrete foundation.
4.3.4
Vibration dampers
The ComPAC unit is placed on vibration dampers. These dampers are calculated to the chiller
weight and designed for minimum 70% vertical isolation (100% capacity) which will be sufficient
for chiller units installed on solid concrete floors.
ComPAC units must be level, and it is therefore recommended to install the unit on machine feet.
The load on the machine feet must be distributed evenly so the deflection will be roughly the same
on each of the feet, see Fig. 17.
Deflection of a machine foot can be adjusted by increasing or reducing the load compared to the
other supports by turning the adjusting rod.
For installation in storey buildings, specially designed vibration dampers are often required. In
such cases, it is recommended to replace the machine feet with specially designed vibration
dampers.
Contact a vibration expert or a Johnson Controls Denmark representative for more information.
U n loa d e d s t a te
Fig. 17: Machine foot
4.3.5
ComPAC with variable speed drive (VSD)
The ComPAC unit is available with:
•
fixed speed
•
variable speed drive (VSD)
The motor for the screw compressor is controlled by a frequency converter. See the Unisab III En-
gineering manual for further description.
For some ComPAC models with screw compressors, mechanical vibrations caused by resonance
may occur in the actual operating range 1000-3600 rpm (6000 rpm for SABflex). This will in some
cases result in an increased vibration level over an interval of approximately 100-150 rpm. As a
rule of thumb, the rpm area is skipped if the vibration level exceeds the recommended maximum
vibration level (see the compressor manual).
All ComPACs are tested from factory. If skipping of rpm is required, this has been done and noted
in the setting list (wirring diagrams).
It is recommended to check the vibration level during pre-start. The resonance rpm area may
change after shipping and installation.
Operating manual - ComPAC
011769 en 2020.03
L o ck n u t
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Lo a d e d s t a te
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