IDEC FL1E SmartRelay - Manual (Page 290)

Applications
276 IDEC SmartRelay Manual 
8.3 Air-conditioning system
8.3.1 Requirements for an air-conditioning system
The air-conditioning system supplies fresh air to a room or
exhausts the contaminated air from a room. Let us examine
following example:
Fresh-air fan
Flow sensor
Flow sensor
Exhaust fan
• The room is equipped with an exhaust fan and a fresh-air
fan.
• Both fans are monitored by means of a flow sensor.
• An excess atmospheric pressure may never develop in
the room.
• The fresh-air fan must only be switched on if safe
functioning of the exhaust fan is signaled by the flow
sensor.
• A warning lamp indicates failure of a fan.