Daikin EWWD VZ Series, Installation, Maintenance And Operating Manual

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Minimum water content in the system
For correct EWWDxxxVZ machine operations and the necessary operating stability, it is important to ensure a
minimum water content in the system. An accumulation tank with suitable volume may be required for this
purpose.
The minimum water content must be calculated by considering the following specifications:
Application EWWD 450÷C11 EWWD C13÷C21
Conditioning 3.3 lt/kW 2.5 lt/kW
Process 6.6 lt/kW 5.0 lt/kW
Variable capacity 6.6 lt/kW 5.0 lt/kW
Note: The EWWD450 ÷ C11 units are machines with a single compressor
The EWWDC13 ÷ C21 units are machines with two compressors
Calculation example for EWWDC11VZ XS units
Cooling capacity at 100% = 1053 kW
Minimum system volume for conditioning: 1053 x 3.3= 3475 lt
Minimum system volume for processing: 1053 x 6.6= 6950 lt
Minimum system volume at variable capacity: 1053 x 6.6= 6950 lt
Note: The calculation formula described above, takes into account several factors such as the compressor stop
time and the admissible temperature difference between the last compressor stop and start. In this regard, the
minimum water content calculated refers to the machine operations in a normal climate control system. If the
machine is used for process activities or if higher operating stability is required, we recommend doubling the
calculated water content. In very simple systems, an inertial accumulation tanks may be necessary on the
hydraulic circuit to reach the required minimum water volume. Adding this component must guarantee correct
water mixing and, therefore, we recommend you select a tank that includes an internal diaphragm for this
purpose.
Note: If the evaporator water circuit operates in a variable flow system, the minimum water flow rate must not be
less than 50% of the water flow rate at nominal conditions and the variation should not be greater than 10% of
the nominal flow per minute.
Note: If the evaporator water circuit operates in a variable flow system, the minimum water flow rate must not be
less than 50% of the water flow at nominal conditions, and the variation should not be greater than 10% of the
nominal flow per minute.