90•dap4UserManual
NO AIRFLOW ALARM
1.Whennoairowisdetectedviatheairowswitchorcurrentsensingrelay,thecooling,re-
heat,humidicationanddehumidicationfunctionsarelockedoutuntilthealarmconditionis
corrected. Menu K – Alarms and Limits, allows adjustment of the alarm delay from 5 to 180
seconds in 5 second increments. Adjustment is to minimize false alarms due to air turbulence.
2. On chilled water units a “FAN FAILURE” alarm is included in addition the NO AIRFLOW
ALARM. On units with multiple plug fans, if a fan failure alarm is detected, the speed of the
remaining motors will ramp up to 100%, if the dap4 is programmed to constant speed mode.
Ifprogrammedtooneoftheotherfanspeedcontrolmodes,thefanswillrampuptomaximum
speed.Reheatandhumidieroperationswillbeinhibitedduringafanfailurealarm.The
chilled water valve will continue to modulate, the remaining fans will continue to run and the
unit continue to cool. The fan speed control will automatically return to normal operation mode
when the fan failure is corrected.
DIRTY FILTER ALARM
Whenadirtylterisdetected(throughtheunitmountedpressuredifferentialswitch),theaudio
alarm is activated and a “Dirty Filter” message will be displayed on the display module until the
condition is corrected.
FIRESTAT TEMPERATURE ALARM
1.Therestattemperaturealarmisprogrammablefrom100to150°F(SeeMenuK–Alarmsand
Limits).
2.Ifthereturnairtemperaturereachestherestattemperaturealarmlimit,theblower,cooling,
reheat,humidicationanddehumidicationfunctionsareimmediatelyterminated.
3. The audio alarm is activated and “Firestat Tripped – Unit Shutdown” message will be displayed
on the display module until the condition is corrected.
4. The alarm will prevent the unit from operating until the alarm is corrected.
HIGH TEMPERATURE ALARM LIMIT
1. The high temperature alarm limit is programmable (See Menu K – Alarms and Limits). The
range is from 70 to 90°F. It can also be disabled.
2. If the alarm is not disabled and the return air temperature rises above the high temperature
alarm limit, the audio alarm is activated and a “High Return Air Temperature” message is dis-
played on the display module.
3. The audio alarm is a warning only and will not prevent any of the unit functions form operating.
4. The alarm will remain until the alarm condition is corrected.
LOW TEMPERATURE ALARM LIMIT
1. The low temperature alarm limit is programmable (See Menu K – Alarms and Limits). The
range is from 55 to 75°F. It can also be disabled.
2. If the alarm is not disabled and the return air temperature falls below the high temperature
alarm limit, the audio alarm is activated and a “Low Return Air Temperature” message is dis-