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11. GENERAL OPERATION
The Zehnder Eversky decentralised dual flow ventilation unit includes the following features as standard:
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Management of the CO₂ content of the ambient air:
The control system continuously adjusts the speed of the supply and exhaust fans to maintain the CO₂ level in the
room or space at a level compatible with comfort and hygiene requirements. As the measured CO₂ level is the image of
the occupancy rate of the room, when the CO₂ level increases, the speed of the fans increases to increase the
renewal, and vice versa. The energy consumed by the fans and the noise level of the unit are thus continuously
optimised.
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Management of thermal energy recovery:
Depending on the (adjustable) temperature setpoint, the control continuously adapts the heat recovery rate of the
recovery unit in order to keep the room warm in cold periods, or cool in hot periods. When the conditions are met, the
unit can deactivate heat recovery and switch to free cooling or free heating mode. The fully configurable night cooling
function allows the air flow to be forced at night to lower the temperature of the room at the beginning of the day, thus
improving thermal comfort and limiting energy consumption linked to the use of any additional devices (air
conditioning, reversible heat pump, etc.).
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Supply air heating management (if equipped with electric or hot water coil) PREMIUM or INFINITE versions):
Optionally, Zehnder Eversky can be fitted with a heating coil to maintain the thermal comfort of the room/place in
which it is installed.
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Protection against icing of the recovery unit by modulating bypass:
At low outside air temperatures, the flow rate of fresh air through the recovery unit is continuously optimised to avoid
the recovery unit icing up and to maximise energy performance.
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Fresh air preheating management (if equipped with a fresh air preheating coil) INFINITE version:
In order to maximise the operating range of energy recovery, especially in the cold season, Zehnder Eversky manages
the preheating of the fresh air to avoid the recovery unit icing up.
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Insulation:
The Zehnder Eversky ventilation unit is equipped as standard with motorised isolation dampers that close when the
unit is switched off or in the event of a power failure to prevent any unwanted air flow between the room/place and the
outside.
11.1. Start-up sequence of the unit
Start-up sequence:
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The return air fan or the VAR pressure control mode starts at the same time as the return air damper.
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The supply air fan or the VAS pressure control mode starts after a preset delay (20s) together with the fresh air
damper.
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The temperature control starts according to the configured control mode. The electric heater (PREMIUM BE or
INFINITE BE version), only starts if the fresh air flow control pressure switch (LIFO) allows it (VAS runback). Pumps that
were not yet activated are switched on.
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After a preset time, the alarm management function is activated. The system is now in normal mode.
The system starts up when one of the following conditions is met:
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The time programme (clock) for normal or low speed is set to "On".
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The unit is started in manual mode from the controller.
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One of the digital inputs for forced operation is activated.
Zehnder Eversky
