Daikin EWWD VZ Series, Installation, Maintenance And Operating Manual

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Evaporator frost protection
1. If the machine is idle during the winter, drain and rinse the evaporator and chilled water pipes with glycol.
Drain and air vent connections are included on the evaporator for this purpose.
2. We recommend adding glycol in proper proportion to the condenser cooling system. The freezing
temperature, of the water-glycol solution, must be at least 6° C lower than the expected minimum ambient
temperature.
3. Insulate pipes especially chilled water ones to avoid condensation.
Note: Damage caused by freezing is not covered by warranty, therefore, Daikin Applied Europe SpA
cannot be held liable.
Condenser protection and design considerations
If lake, river or ground water is used as the cooling fluid and the water valves have a leak, the condenser and
liquid refrigerant line temperatures could drop under room temperature when the machine is off. This problem
occurs when cold water circulates through the condenser and the unit remains off waiting load. If this happens:
1. Turn off the condenser water pump when the compressor is off.
2. Check that the liquid line expansion valve is working properly.
Condensation control with evaporative cooling tower
The minimum condenser inlet water temperature should not be less than 20° C at full water tower flow rate.
If the water temperature must be lower, even the water flow must be reduced proportionately.
To modulate the water flow to the condenser, install a three-way by-pass valve. The figure shows how the three-
way valve is applied to cool the condenser. The three-way valve can be activated by a pressure actuator which
guarantees proper condensing pressure in the case where the water temperature entering the condenser is less
than 20° C.
In place of a valve with pressure actuator you might use a three-way servo-operated valve or a circulation pump
controlled by an inverter. Both of these two devices may be controlled by an analog 0-10 Vdc signal issued by
the machine's electronic controller according to the water temperature entering the condenser.
Fig. 3
– Condenser control scheme with cooling tower
1
2
1
– Cooling Tower
2 - Condenser