27
OPERATION
Cooling, Unit with EconoMi$er X
For occupi ed mode operation of EconoMi$er X, there
must be a 24V signal at termi nals R and OCC. Removing
the signal at OCC places the EconoMi$er X control in
unoccupi ed mode.
During occ upied mode operation, indoor fan operation
will be accompanied by economizer dampers moving to
minimum position setpoint for ventilation. If indoor fan i s
off, dampers will close. During unoccupied mode
operation, dampers will remain closed unless a cooling
(by free cooling) or DCV demand is received.
When free cooling using outside air is not available, the
unit cooling sequenc e will be controlled directly by the
space thermostat. Outside air damper position will be
closed or minimum position as determined by occupancy
mode and fan signal.
When free cooling is available as determined by the
appropria te changeover command, a call for cooling (Y1
closes at the thermostat) will cause the economizer control
to modulate the dampers open a nd closed to maintain the
unit supply air temperature. Default supply air
temperature is 53° F with a range of 38° to 70° F.
If 100% outside air is not capable of satisfying t he
setpoint, space temperature will rise until Y2 is closed.
The economizer control will call for PMV operation.
Dampers will modulate to maintain SAT setpoint
concurre nt with PMV operation.
When space temperature demand is satisfied (thermostat
Y1 opens), dampers return to minimum damper position if
indoor fan is running or fully closed if fan is off.
Damper movement from full closed to f ull open (or vice
versa) will take between 1 - 1/2 and 2- 1/2 minutes.
Heating with EconoMi$er X
During occ upied mode operation, indoor fan operation
will be accompanied by economizer dampers moving to
minimum position setpoint for ventilation. If indoor fan i s
off, dampers will close. During unoccupied mode
operation, dampers will remain closed unless a DCV
demand is received.
When the room temperature calls for heat (W1 closes), the
heating controls are energized.
TROUBLESHOOTING
Power Loss (Ou tage or Brownout)
All setpoints and advanced set tings are restored aft er a ny
power loss or interruption as all settings are stored in the
Economizer controller’s non- volatile flash memory.
NOTE: If the power falls below 18 VAC, the W7220
controller module assumes a power loss and the five
minute power up de lay will become funct ional when
power returns above 18 VAC.
Alarms
The Economizer modul e provide s alarm messages that
display on the 2- line LCD.
NOTE: When the unit is power on, the module waits
several seconds before checking for alarms. Thi s allows
time for all 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 five minutes, the alarms menu
displays and cycles through the active alarms. You can
also navigate to the alarms menus at any time. See Table 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 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 five seconds.
40QQ
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