Innovative ice detection and control - VEX340H
High-efficiency counter flow heat exchangers can suffer icing, especially if the extracted room air is humid. When the energy from this extracted air is used (when the air cools), the moisture condenses to water vapour, which collects in the heat exchanger.
The high efficiency means that some areas inside the heat exchanger become very cold and in these areas condensed water will freeze and form ice. This can block the air flow.
To ensure EXHAUSTO counter flow heat exchangers can operate in areas that have temperatures below -3 °C EXHAUSTO has developed a return air system. When ice begins to form inside the counter flow heat exchanger, the VEX340H control system circulates up to 30 % of the warmed air back into the cold supply air. This raises the temperature of the outdoor air and the problem of icing is reduced.
Return air principle

Frost protection methods
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NB This function is only active for air regulation methods 2 and 5. |
Air regulation – there are seven different air regulation methods:
Airflow control
2. Constant airflow
Constant pressure regulation of extract air
3. Constant pressure-regulated extract air with fixed supply air
5. Constant pressure-regulated extract air with slave-controlled supply air
Constant pressure regulation of supply air
4. Constant pressure-regulated supply air with fixed extract air
6. Constant pressure-regulated supply air with slave-controlled extract air
Constant pressure regulation of both extract air and supply air
7. Constant pressure regulation of both extract air and supply air
8. External control of fan speeds