13
Fig. 15 - Barometric Relief Flow Capacity
0
500
1000
1500
2000
2500
0
0.05
0.1
0.15
0.2
0.25
0.3
R
ELI
EF
F
LO
W
(C
FM
)
RETURN DUCT STATIC PRESSURE (in. wg)
Small
Cabinet
Large and
Extra
Large
Cabinet
Fig. 16 - Return Air Pressure Drop
0
1000
2000
3000
4000
5000
6000
0
0.1
0.2
0.3
0.4
RE
T
URN
AI
R F
L
O
W
(CF
M
)
RETURN DUCT STATIC PRESSURE DROP (in. wg)
Small Cabinet
Large Cabinet
Extra Large Cabinet
Table 12 - Operating Issues and Concerns
Issue or Concern
Possible Cause and Remedy
My outdoor temperature reading on the
STATUS menu is not accurate
Check the sensor wiring:
• Enthalpy sensors are to be wired to the S-Bus terminals.
• Temperature sensors are to be wired to the OAT and MAT terminals.
If my enthalpy sensor drifts in accuracy
over time, can I re-calibrate it?
The sensor is not able to be re-calibrated in the field. However there is a menu
item under the ADVANCED menu where you are able to input a limited off set in
temperature and humidity for each sensor you have connected to the economizer.
Can I go back to factory defaults and start
over?
Under the SYSTEM SETUP menu you can change the setpoints to the factory
defaults.
Will I be able to see the LCD screen when it
is in the unit?
The LCD screen has a backlight that is always illuminated.
What is a good setpoint for the Mixed Air
Temperature (MAT)?
The mixed are temperature is the temperature of air that you want to supply to the
space. In a commercial building, this is between 50 to 55
o
F (10 to 13
o
C). The mixed
are is the mixing of the return air and the outdoor air.
I am using enthalpy sensors. Why did
the control ask me to input a dry bulb
changeover temperature?
In the even the humidity sensor in the enthalpy sensors fails, the backup algorithm in
the control is to default to the temperature sensor in the enthalpy sensor.
In checkout, the outdoor damper closes when
I command it to open.
Check the actuator linkage or rotation. In the CHECKOUT mode, the outdoor damper
should drive open or closed with the return air damper having the opposite effect.
How do I set my minimum position?
The minimum position is set using the VENTMIN and VENTMAX setup in the
SETPOINTS menu. VENTMIN is the minimum ventilation required when using an
occupancy sensor and VENTMAX is the minimum ventilation when not using an
occupancy sensor for Demand Control Ventilation. The VENTMAX position is set the
dame as with the potentiometer on the analog economizers and is the output voltage
to the damper actuator. The range is 2 Vdc closed OA damper and 10 Vdc open OA
damper.
What if my damper does not go completely
closed in the checkout operation?
Check the damper linkage or hub to make sure the damper is able to close com-
pletely.
How do I set the OCC?
There are two setting for the OCC setting, INPUT and ALWAYS, INPUT is from the
space thermostat, if it has an occupancy output. ALWAYS is the unit in the occupied
mode, if the economizer is powered (fan on).
Does the economizer save my program val-
ues if the unit loses power?
Yes, once the changes are stored in the controller they will be stored until they are
changed by the operator.
If the unit is left in checkout, how long will the
unit stay in checkout mode without input?
The unit will remain in checkout for 10 minutes, then return to normal operation.
