Microprocessor Controller for DOAS
26
®
T
HIS
SCREEN
DISPLAYS
THE
E
XHAUST
F
AN
D
ELAY
AND
E
NABLE
BASED
ON
O
UTSIDE
A
IR
D
AMPER
P
OSITION
.
The exhaust fan delay will begin once the damper sequence is complete. This
delay can be used to offset starting times between the supply fan and exhaust
fan. This screen also provides the ability to enable the exhaust fan on a set
outdoor air damper position if the unit is equipped with a modulating outdoor air
damper.
T
HIS
SCREEN
DISPLAYS
M
INIMUM
AND
M
AXIMUM
E
XHAUST
F
AN
S
PEED
P
ERCENTAGES
.
The speed set point is the proportional percentage of the analog output from the
controller to the VFD.
25% Speed = Min speed
100% Speed = Max speed
Possible Setpoint Sources:
Local
–
The fan speed will be constant; set from screen (e.g. 100%).
BMS
–
The BMS can directly control the fan speed (requires BMS communication
option).
Space Pressure
–
Fan speed is determined by building pressure control loop.
Supply Fan Tracking with Offset
–
The exhaust fan will track the supply fan,
between a minimum and maximum position. An offset can be added to achieve
the proper balance.
Outdoor Air Damper Tracking
–
The exhaust fan will proportionally track the
outdoor air damper, between a minimum and maximum position.
Return Duct Static Pressure
–
Fan speed is determined by duct pressure control
loop.
Control Variables
Fan Control
Exhaust Fan Control
The
Exhaust Fan Control
menu allows the user to adjust exhaust control
setpoints.
Menu
