Our switches all have a similar statement in the installation guide about having 5 inches around the exhaust fans.  I'm not clear what that means.

• Do I leave 1U above and below the switches (5" diameter from the centre of the fans);
• Do I leave 2.5U either side of the switch (5" radius from the centre of the fans);
• Or do I leave 3U above and below the switch (5" from the edge of the fans, so fan radius + 5")?