Version 5.2_2022 (January 26, 2022)
17
7.
Control Technology
Components for control technology are integrated into the Aqua Cool. The control strategy is determined by
selecting cooling or heating via the software.
For control technology, please refer to the user manual supplied with the product, which can also be found on
our website
In OC Verhulst units that are frequency-controlled or equipped with EC technology, residual current devices,
neutral grounding can be used as extra protection, provided that local safety regulations are observed. A
grounding fault can cause a direct current in the discharge current. Do not use type A residual current devices
as they are not suitable for DC leakage currents. If residual current devices are used, they must comply with
local regulations. The residual current devices used must be suitable for protecting a unit with a direct current
(DC) in the grounding leakage flow (3-phase DC bridge). In addition, they must be suitable for a high leakage
current and for a short discharge current when switched on.
7.1.
Air inlet temperature sensor:
Temperature sensor is mounted in the space between outdoor air inlet dampers and filters.
7.2.
Supply air temperature (internal/external) sensor:
The internal temperature sensor is mounted in the space between the fans and supply dampers. It is also
possible to connect an external temperature sensor via a connection outside the cabinet. When this is
connected, the control strategy automatically changes to external temperature sensor.
7.3.
Fluid supply / return temperature sensor:
For flow control, a temperature sensor is mounted on the supply and return lines of the coil.
7.4.
Dual position switch (start/stop):
The fans and the three-way valve can be switched on or off via the dual position switch. Optionally, it is
possible to control the unit with a time schedule (see defrosting cycle).
7.5.
Control panel:
Everything can be set via the control panel. The main screen contains the most important data. Fan speed,
three-way valve control and temperature setpoint.
7.6.
Fans:
The fans are controlled via a potentiometer (0-100%) and a dual position switch stop /start). The controller
translates this to the EC fan via ModBus and is controlled by it.
7.7.
Three-way valve:
The valve is controlled via 0-10V. The control is based on a PI control with setpoint and supply air
temperature or room temperature.
