25
TROUBLESHOOTING
For a list of common operating issues and concerns, see
Table 15.
Power Loss (Outage or Brownout)
All set points and advanced settings are restored after any pow-
er loss or interruption, as all settings are stored in the Econo-
mizer 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 devic-
es (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.
The Alarms menus can be navigated at any time. See Table 11
for the Alarms menu.
CLEARING ALARMS
Once the alarm has been identified and the cause has been re-
moved (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 an alarm still exists after it has been cleared, it will re-
display within 5 seconds.
Table 15 — 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
recalibrate it?
The sensor is not able to be re-calibrated in the field. However, there is a menu item
under the ADVANCED menu to input a limited offset in temperature and humidity for
each sensor that is connected to the economizer.
Can I go back to factory defaults and start over?
Under the SYSTEM SETUP menu, you can change the set points 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 set point for the Mixed Air Temperature
(MAT)?
The Mixed Air Temperature is the temperature of air to supply to the space. In a
commercial building, this is between 50°F and 55°F (10°C and 13°C). Mixed air is the
combination of return air and outdoor air.
I am using enthalpy sensors. Why did the control ask me to
input a dry bulb changeover temperature?
If 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 when using a CO
2
sensor?
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 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).
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.
