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If for any reason the rotor is blocked, the motor will electronically switch o. Before looking for blockage
make certain to remove power from the unit. Once the blockage is cleared the motor will automatically
restart when powered on.
If there is an alarm condition indicated as “NO AIRFLOW”, all active functions (cooling, heating and
humidication will stop until the alarm is cleared.
EC motors have an under voltage protection. If the power supply voltage falls below 150 VAC/3Ø
(for 230 volt motors) 290 VAC/3Ø (for 460 motors) for a minimum of ve (5) seconds, the motor will
automatically switch o and an alarm condition (NO AIRFLOW) will be energized and displayed. If the
power supply voltage returns to the correct values, the motor will automatically restart.
NOTE: The unit’s control panel (dap4™) has a time delay before the NO AIRFLOW
alarm is energized. It is adjustable from 5 to 180 seconds (in 5 second increments). On
site where a voltage problem is known to exist, the delay can be adjusted to eliminate
“nuisance” alarms until the problem is corrected.
8.6.2 TESTING
To test the plenum fan modules in manual mode, wire a 9 volt battery across the plug fan control signal
(see schematic for wiring details). Be certain to disconnect both terminals (+ and -) from the analog
output. This will enable the fan control signal at approximately 90%. The fans will spin at near full
speed if the contactors are enabled.
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