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- It is forbidden to access the electrical components without using an insulating
platform. Do not access the electrical components if water and/or moisture
are present.
- All operations on the refrigerant circuit and on components under pressure must
be carried out by qualified personnel only.
- Replacement of a compressor or addition of lubricating oil must be carried out
by qualified personnel only- Sharp edges can cause wounds. Avoid direct contact.
- Avoid introducing solid bodies into the water pipes while the machine is connected to the system.
- A mechanical filter must be installed on the water pipe connected to the heat exchanger inlet.
- The machine is supplied with safety valves, that are installed on both the high
and the low pressure sides of the refrigerant circuit.
In case of sudden stop of the unit, follow the instructions on the Control Manual Operating Manual
which is part of the on-board documentation delivered to the end user with this manual.
It is recommended to perform installation and maintenance with other people. In case of accidental
injury or unease, it is necessary to:
- keep calm
- press the alarm button if present in the installation site
- move the injured person in a warm place far from the unit and in rest position
- contact immediately emergency rescue personnel of the building or if the Health Emergency
Service
- wait without leaving the injured person alone until the rescue operators come
- give all necessary information to the the rescue operators
System Water Volume
All chilled water systems need adequate time to recognize a load change, respond to that load
change and stabilize, without undesirable short cycling of the compressors or loss of control.
In air conditioning systems, the potential for short cycling usually exists when the building
load falls below the minimum chiller plant capacity or on close-coupled systems with very
small water volumes.
Some of the things the designer should consider when looking at water volume are the
minimum cooling load, the minimum chiller plant capacity during the low load period and the
desired cycle time for the compressors.
Assuming that there are no sudden load changes and that the chiller plant has reasonable
turndown, a rule of thumb of "gallons of water volume equal to two to three times the chilled
water gpm flow rate" is often used.
A properly designed storage tank should be added if the system components do not provide
sufficient water volume.
Low Condenser Water Temperature Operation
When ambient wet bulb temperature are lower than design, the condenser water temperature
can be allowed to fall. Lower temperatures will improve chiller performance.
Up to 300 Tons
Daikin centrifugal chillers up to 300 tons are equipped with electronic expansion valves (EXV)
and will start and run with entering condenser water temperatures as low as shown in Figure 3
or as calculated from the following equation on which the curves are based.
12
Centrifugal Chillers
D-EIMWC00804-14EN
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