Carrier 50LC 07, Инструкции по обслуживанию и техническому обслуживанию, Страница: 56 / 100

56
Table 20 – 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 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.
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 Supply
Air Temperature (SAT)?
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.
I am using enthalpy sensors. Why did
the control ask me to input a dry bulb
changeover temperature?
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.
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 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.
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 completely.
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 values 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.