Supply air unit VEKC - Integrated Control Equipment Curo
22
FläktGroup DC_9965GB_20190124_R3
Specifications are subject to alteration without notice
5.1 HEATING AND COOLING
The unit is configured differently regarding to heating and cooling,
see below.
HEATING
• No heater
• Electrical post heater
• Hot water coil
COOLING
• No cooling
• Water
• DX, On/Off
CONTROL FUNCTION
The control function works as follows:
Regardless of control mode the unit tries to achieve the desired
setpoint.
This is done by the unit depending on the needs, demand for heat
recovery, heating or cooling. Built into the system is also a dead
zone. The dead zone function (usually 2°C) acts as a temperature
zone between heat recovery and cooling where neither calls for
heat recovery or cooling.
Figure 1. The figure shows the controller’s output signals to the various com-
ponents at different temperatures. The zone between T1 and T2 is
called the dead zone.
5. CONTROL FUNCTIONS
Heating
Cooling
Control signal, %
Sequence control
Temperature, °C
100
50
T0
T1
T2
T3
5.2 TEMPERATURE CONTROLS
VEKA has two temperature control options, supply air, and room
control.
In addition it is possible to use outdoor temperature compensa-
tion. This control mode cannot be combined with room control.
To obtain other control modes, first the controller must be chang-
ed from standard mode to cascade mode. Then control mode is
selected by changing the cascade reference to room control (0)
or outdoor temperature compensation (1). Below is a description
of the different control modes.
SUPPLY AIR CONTROL
To maintain a constant supply air temperature, the controller
works with the setpoint and the supply air temperature. Based on
these parameters, the current heating and cooling sequences are
controlled.
ROOM CONTROL
Room control gives the best control of temperature in a specific
room and is used when only one unit serves this room. This
method works best for larger premises.
This enables the unit to regulate the supply air temperature in a
way that maintains the room temperature at a desired level.
Limitation of the supply air temperature (min. temp. and max.
temp.) ensures that the supply air temperature is maintained
within the set range.
DEFAULT PARAMETERS FOR ROOM CONTROL
1. Controller = 2
Selects cascade control
2. Cascade reference = 0 Selects room control
3. Cascade A = 0.5
When the sensor gets colder than gi-
ven setpoint value
4. Cascade B = –0.5
When the sensor gets warmer than
given setpoint value
5. Min. temp. = 15°C
Sets lowest supply air
temperature
6. Max. temp. = 25°C
Sets highest supply air temperature
EXAMPLE
1. Setpoint = 18°C
2. Room temperature = 22°
This means that the new calculated setpoint for the supply air
controller is:
Calculated setpoint = se (setpoint – room air temperature)
x cascade B = 18 – (18 – 22) x (–0.5) = 16°C.
