Lennox ROOFTOP FLEXY FXK 100, Installation, Operating And Maintenance, Page: 31 / 110

IOM – FLEXY II – 1007 – E Page 29
ECONOMISER
Free cooling can be provided through the use of fresh air which is more appropriate
than excessiv e cooling amounts of return air.
The economiser is f actory fitted and tested prior to shipment.
It includes two dampers operating f rom a 24V actuator
RAIN HOOD
It also includes a factory f itted rain hood. Hoods is f olded during transportation to limit
risks of damage and must be unf olded on site as shown on f ig. 9
EXTR ACTION
Installed with economiser assembly, the gravity exhaust dampers reliev e the pressure
when outside air is introduced into the system.
When large amount of f resh air is introduced into the system power exhaust fans can be used to equalise the pressures.
The extraction fan runs when return air dampers are being closed and supply air blower is in operation. The extraction f an runs
when outdoor air dampers are at least 50% open (adjustable value). It is overload protected.
NOTE: When horizontal flow configuration is required, the multidirectional roof curb will be installed.
0-25% FRESH AIR MANUAL
It is enough to loosen the mobile grid's screws and to make it slip.
0%: screw into limit stop on the right
25%: screw into limit stop on the left
F LEXY II PRINCIPLE SKETCH
M ULTIDIRECTIONAL ROOFCURB
PRINCIPLE SKETCH
E NERGY RECOVERY MODULE PRINCIPLE SKETCH R ETURN ROOFCURB PRINCIPLE SKETCH
F
RESH
A
IR
R
ETURN
A
IR
E
XHAUST
A
IR
S
UPPLY
A
IR
ECONOMISER AND EXTRACTION
Fig. 9