• 12 • Installation - Operation - Maintenance manual (IOM) • AIR COOLED CHILLERS & SPLIT UNITS - 0105-E
A main isolator switch must be inserted between the end of the power supply cable and the unit to enable total
isolation of the latter when necessary. Chillers are supplied as standard without a main isolator switch. This is
available as an option.
WARNING
Wiring must conform to applicable regulations. The type and location of fused isolators must also conform
with regulations. For the sake of safety, install them where they can be seen and in easy reach of the unit.
Units must have full earthing continuity.
IMPORTANT
Operation of a unit with the wrong power supply or with excessive phase imbalance constitutes abuse and
is not covered by the LENNOX warranty. If phase imbalance exceeds 2 % for voltage and 1 % for current,
contact your local electricity company immediately before powering up the unit.
3.6 - SOUND LEVELS
Liquid chillers are a significant source of noise in refrigeration and air conditioning systems.
Account is taken of technical constraints, both in design and manufacturing, sound levels cannot be improved much
further than specified.
Sound levels must therefore be accepted for what they are, and the area surrounding the chillers should be treated
as necessary. The quality of installation can either improve or decrease initial sound characteristics: it may be
necessary to provide further treatment such as sound-proofing or installation of screens around units installed
externally. The choice of the location for the installation can be of great importance : reflection, absorption,
transmission of vibrations.
The type of unit support is also very important : inertia of the room and the structure of the walling, interfere with
the installation and its behaviour.
Before taking any other steps, first determine whether the sound level is compatible or not with the environment,
what it is perfectly justifiable and that these measures envisaged will not cause unreasonable cost.
Determine what level of sound proofing is necessary on the equipment, the installation (silencer, vibration isolators,
screens) and on the building (reinforcement of flooring, false ceilings, wall coverings).
It may be necessary to contact an engineering office that specialises in sound abatement.
3.7 - CONNECTION OF SPLIT UNITS
Connections between the unit and the condenser must be made by a qualified refrigeration engineer and require
several important precautions.
In particular, the shape and dimensions of the hot gas lines must be carefully designed to ensure proper oil return
in all cases and prevent liquid from returning into the cylinder heads when the compressor is stopped.
On units fitted with capacity reducers, the piping sizes must be calculated so that gas velocity is sufficiently high
when the unit is operating on capacity reduction.
Non application of these precautions will cancel the compressor warranty.
We recommend to follow ASHRAE recommendations.
3.7.1 - Liquid line sizing
Determine the size of liquid lines using :
1) Operating conditions at full load.
2) Maximum pressure drop of 100 kPa
3) Liquid velocity under 2 m/s (to avoid liquid slugging).
4) For liquid risers, make sure that liquid subcooling is sufficient to counteract the loss of static pressure and
prevent gas flashing.
3.7.2 - Discharge lines and suction lines
Calculate these to obtain a gas velocity in vertical sections that enables compressor oil migration and steady return
to the compressor (tables C and D - page 15).
Determine the dimensions of vertical lines using the following tables.
Horizontal lines may be bigger in order to compensate pressure drop in vertical lines.
The total pressure drop in the piping has to be lower or equal to 1°C at saturation pressure on the suction side.
INSTALLATION - TRANSPORT - HANDLING
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