11
TROUBLESHOOTING
Power Loss (Outage or Brownout)
All setpoints and advanced settings are restored after any
power loss or interruption, as all settings are stored in the
Economizer controller’s non--volatile flash memory.
NOTE
: If the power goes below 18 Vac, the W7220
controller module assumes a power loss and the 5 minute
power up delay will become functional when power
returns above 18 Vac.
Alarms
The Economizer module provides alarm messages that
display on the 2--line LCD.
NOTE
:
Upon power up, the module waits several
seconds before checking for alarms. This allows time for
all the configured devices (e.g. sensors, actuator) to
become operational.
If one or more alarms are present and there has been no
keypad activity for at least 5 minutes, the Alarms menu
displays and cycles through the active alarms.
You can also navigate to the Alarms menus at any time.
See Table 2 on page 6 for the Alarms menu.
Clearing Alarms
Once the alarm has been identified and the cause has been
removed (e.g. replaced faulty sensor). the alarm can be
cleared from the display.
To clear an alarm, perform the following:
1. Navigate to the desired alarm.
2. Press the
button.
3. ERASE? displays.
4. Press the
button.
5. ALARM ERASED displays.
6. Press the
(Menu up/Exit) button to complete the
action and return to the previous menu.
NOTE
: If the alarm still exists after you clear it, it is
redisplayed within 5 seconds.
Table 9 – 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 Mixed Air
Temperature (MAT)?
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.
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.
LLECO
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