Override control on/off
Fig. 18: Override control
When using a 24 V AC supply voltage, special operating
states, so-called override controls, can alternatively be
activated.
For this purpose, it is necessary to have a different cir-
cuit with a diode circuit and volt-free switch contacts,
provided by others.
Switch S2 closed - CLOSED (closed position)
Switch S3 closed - OPEN (open position)
Note
: this functionality is only available with AC supply
voltage.
All override controls can be combined both with each
other and with the different switching options. When
combining several override controls the switches must
be interlocked to prevent short-circuits.
With activation of the override control "damper blade
CLOSED", the VAV terminal unit is put into the closed
position. Depending on the design of the VAV terminal
unit, residual leaks may remain, or an air-tight shut-off
can be achieved. For more detailed information, see
technical data of the VAV terminal unit.
Control V
min
... V
max
with 20 mA control signal
Fig. 19: Variable volume flow
The connection of a reference signal from 0 to 20 mA is
also possible. For this purpose, a resistance of 500 Ω is
placed between the ground and input (w). The actual
value output (U) is always available as voltage signal
0–10 V DC.
Wiring
Connection diagrams
Control component Easy for VAV terminal units
20
