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Issue or Concern
My outdoor temperature reading on the STATUS menu
is not accurate
If my enthalpy sensor drifts in accuracy over time, can I
re - calibrate it?
Can I go back to factory defaults and start over?
Will I be able to see LCD screen when it is in the unit?
What is a good setpoint for Mixed Air Temperature
(MAT)?
I am using enthalpy sensors. Why did the control ask
me to input a dry bulb changeover temperature?
In checkout, the outdoor damper closes when I
command it to open.
How do I set my minimum position?
What if my damper does not go completely closed in
the checkout operation?
How do I set the OCC?
Does the economizer save my program values if the
unit loses power?
If the unit is left in checkout, how long will the unit stay
in checkout mode without input?
Table 12 – Operating Issues and Concerns
Check the sensor wiring:
S
Enthalpy sensors are to be wired to the S - Bus terminals.
S
Temperature sensors are to be wired to the OAT and MAT terminals.
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.
Under the SYSTEM SETUP menu you can change the setpoints to the factory defaults.
The LCD screen has a backlight that is always illuminated.
The mixed air temperature is the temperature of air that you want to supply to the space. In a
commercial building, this is between 50 to 55° F (10 to 13° C). The mixed air is the mixing of the return
air and the outdoor air.
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.
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.
M
inimum position is set using VENTMIN and VENTMAX setup in SETPOINTS menu. VENTMIN is
minimum ventilation required when using an occupancy sensor and VENTMAX is minimum
ventilation when not using an occupancy sensor for Demand Control Ventilation. 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.
Check the damper linkage or hub to make sure the damper is able to close completely.
There are two setting for OCC setting, INPUT and ALWAYS, INPUT is from space thermostat, if it has
an occupancy output. ALWAYS is unit in the occupied mode, if the economizer is powered (fan on).
Yes, once the changes are stored in controller they will be stored until changed by the operator.
The unit will remain in checkout for ten minutes, then return to normal operation.
2500
2000
1500
1000
500
0
0
0.05
0.1
0.15
RETURN DUCT STATIC PRESSURE (in. wg)
Fig. 35 - Barometric Relief Flow Capacity
Possible Cause and Remedy
Small
Cabinet
0.2
0.25
0.3
27
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