Carrier WeatherExpert 50LC Installation Instructions Manual page 45

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 the LCD
screen when it is in the unit?
What is a good setpoint for the
Supply Air Temperature (SAT)?
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 16 – Operating Issues and Concerns
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.
The sensor are 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 offset 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 supply 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 supply air is the mixing of the return air and the
outdoor air.
In the event 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.
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 Controlled Ventilation. The VENTMAX position
is set the same 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 settings 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).
Yes, once the changes are stored in the controller they will be stored until they are changed by the
operator.
The unit will remain in checkout for 10 minutes, then return to normal operation.
Fig. 53 - - Typical EconoMi$er
Possible Cause and Remedy
R X Wiring Diagram
45
a48--- 9390