Daikin EWAD620-C17C-SL, Service Manual

Page: 84 / 304

General Outline ESIE10-01
1–78 Part 1 – System Outline
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11
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1.27 Water Content in Cooling Circuits
The cooled water distribution circuits should have minimum water content to avoid excessive
compressors start and stop. In fact, each time the compressor starts up, an excessive quantity of oil
goes from the compressor sump and simultaneously there is a rise in the temperature of the
compressor motor’s stator due to the inrush current during the start-up.
To prevent damage to the compressors, we have envisaged the application of a device to limit frequent
stops and restarts.
During the span of one hour there will be no more than 6 starts of the compressor. The plant side
should therefore ensure that the overall water content allows a more constant functioning of the unit
and consequently greater environmental comfort.
The minimum water content per unit should be calculated using this simplified formula:
Q
For 2 compressors unit:
M (litres) = ( 0.1595 x
Δ
T(°C) + 3.0825 ) x P(kW)
Q
For 2 compressors unit:
M (litres) = ( 0.1595 x
Δ
T(°C) + 3.0825 ) x P(kW)
where:
Q
M Minimum water content per unit expressed in litres
Q
P Cooling Capacity of the unit expressed in kW
Q
Δ
T Evaporator entering / leaving water temperature difference expressed in °C
This formula is valid for standard microprocessor parameters.
For more accurate determination of quantity of water, it is advisable to contact the designer of the
plant.