The Access utilizes up to two temperature controller at a time. The combination is control mode dependent. It can be:


Supply air controller - keeping stable supply air temperature.


Supply air controller is the top level regulator for all heating & cooling sequences.

The controller is regulating supply air temperature toward "Actual setpoint supply air" within settable minimal and maximal temperature limits.


The user can set desired supply air temperature directly in the following control modes:


1. Supply air

2. Supply air outdoor compensated

5. Room (summer) else outdoor compensated supply air

6. Extract air (summer) else outdoor compensated supply air


The supply air controller in these modes can also be enhanced with neutral zone function.

In the rest of the control modes the setpoint of the Supply air controller is set indirectly (by Room or Extract air controller).



Room controller and Supply air controller - keeping stable room temperature while supply air temperature varies.


The Room controller monitors dynamics of temperature changes of the room. The temperature value is compared to the actual setpoint for the room and that calculates the setpoint for the supply air controller.

Room controller has its own PI settings for adjustment of responsiveness.



Extract air controller and Supply air controller - keeping stable extract air temperature while supply air temperature varies.


The extract air controller monitors dynamics of temperature changes of the extract air. The temperature value is compared to the actual setpoint for the room and that calculates the setpoint for the supply air controller.

Extract air controller has its own PI settings for adjustment of responsiveness.


Related topics:

Neutral zone

Zone control