6.1 Controlling Optima 251
Regulation of room temperature
There are 3 methods of regulation – see service menu item
19. If the supply air regulation has been selected, the
controller will blow in air with the temperature set,
provided that a reheater is fitted to the system. The
supply air temperature is regulated by the supply air
sensor T1.
It is recommended to configure the supply air temperature
2-3 °C below the room temperature.
Relay R8
When the system is running at levels 1, 2, 3 or 4, the relay
will be turned on. This function can be used to e.g. control
the fresh air damper or the exhaust air damper.
6.2 Extra capacity
Water reheating
For systems with water reheaters the motor-operated
reheater will begin to regulate (PI regulation) when the
temperature has fallen 1 °C below the temperature set.
Electrical reheating on / off version
For systems with electrical reheaters the reheater will
connect when the temperature has fallen 1 °C below the
temperature set. If the regulation time is set to e.g. 3
minutes, the temperature sensor T1 will measure if the
temperature is now above or below the temperature set
after 3 minutes. If the temperature is still below the
temperature set, the reheating will keep running. When the
temperature reaches the value set, the electrical reheater
will disconnect.
Electrical reheater (modulating)
For systems with the modulating electrical reheater.
The electrical reheater will automatically adapt to changes
in airflow and temperatures - maintining a constant
temperature according to the requested setpoint.
The controller will be adjusting the electrical output of the
reheater automatically.
Extra cooling
If an extra cooling device is fitted to the system, this will
turn on when the bypass motor is open completely and
turn off again when the bypass motor begins to turn off
again.
Systems with an electrical preheater will regulate in the
same way as an electrical reheater.
6.3 Operating reliability
Safety thermostat
If an error occurs on an electrical heater, the safety
thermostat will disconnect.
The heater is equipped with a fire thermostat that
automatically cuts off the power supply, if the
temperature exceeds 80 °C. If the temperature decreases,
the heater automatically re-engages.
As an additional security there is a built-in thermal cut-
out, which disengages if the temperature exceeds 110 °C.
Re-engaging must be done manually.
Does not apply to PTC electrical heaters.
Remember to disconnect the power to the system before
performing any service on the ventilation system.
6. FUNCTION
17
