The electric heater is activated by the start output of the Access controller. The electric heater is activated when demand for heating arises or with additional condition of minimal airflow - "flow interlock".

Flow interlock - the heater is only started if the fan has reached the minimal airflow required for fan run indication.

It is recommended to use heater with internal overheat protection. The output of the thermostat is captured by the input of the controller and is interpreted as an overheat alarm in case of tripping.

The table below shows a configuration example of the single stage electric heater with an alarm feedback.


Available options & Selection


Sequence selection

Configuration > Functions > Function activation > Heating/Cooling sequence setup

Sequence for heating

| SEQ-A Heating |...|

Sequence settings

Configuration > Functions > Function activation > Heating/Cooling sequence setup > Heating

Type of sequence

|Cooling | Exchanger | Heating | Damper | Fan setpoint compensation |

Type of heater

| Water | Electric | DX | Combi coil |

Type of feedback

| None | Alarm | Run indication |

Digital start output

| No | Yes | Yes with flow interlock* |

Sequence output when recirculation/support

| 0% | 100% | Auto |

Sequence output min limit


Sequence output max limit


Sequence output when the unit is stopped


PID Settings

Configuration > PID controllers > Heating


10 oC

PID settings for the sequence


100 s


0 s

Hardwired interface to the heater

Configuration > I/O allocation settings >

Digital inputs > Overheated electric heater

Any available I/O

Overheat thermostat of the heater. AL-63 is activated on DI tripping

Digital inputs > Feedback sequence

Input for the pressure guard to give alarm if the airflow is insufficient (Topvex units)

Digital outputs > Heating start (SEQ-A)

Start and capacity control signal outputs

Analog outputs > Heating (SEQ-A)

Heater starting and stopping

Data & Settings > Temperature control > Heating

Digital start output start point


Output of the sequence to start and stop the heater (switching points for DO: Heating start)

Digital start output stop point


Graphical representation


90% - indication of sequence output

*Yes with flow interlock - The electric heater can only be activated if supply air fan is running (min flow for indication is reached)