EvoControl Ventilation - Light - MPO
Models: A30T G3 Light, A60T G2 Light
6.6.1 VVX Alarm control / Rotor test
The on/off function means that if the heat exchanger (rotor) stops, 3 attempts are made to start it again before the alarm is triggered.
When the temperature is above zero, the control signal to the heat exchanger and the supply air fan is set to 0 for a period of time; the extract air fan continues to operate according to the set value. The heat exchanger is then tested; if it starts to provide heat again, the unit returns to normal operation.
When the outside temperature is below freezing, it is assumed that the heat exchanger has frozen solid. In this case, the control signal to the heat exchanger and the supply air fan is set to 0 for an extended period, whilst the extract air fan runs at a minimum of 50%. The heat exchanger is then tested; if it starts to function again, a 30-minute defrost cycle is carried out before the unit returns to normal operation.