89 • dap4 User Manual
COMPRESSOR SHORT-CYCLE ALARM
1. Compressor shot-cycle alarm is programmable (See Menu K – Alarms and Limits). A compres-
sor short-cycle alarm will activate if the compressor has been energized ten (10) times in a one
(1) hour period.
2. The alarm is a warning only. Compressor operation will continue.
3. One cycle is a combination of compressor starts for cooling or dehumidification functions.
4. If the compressor is started ten (10) times in a one (1) hours period, the alarm will be activated
and the message “Comp Short- Cycle” will be displayed on the display module.
5. The compressor short-cycle time delay will be increased from five (5) to six (6) minutes for the
next hour.
6. The short-cycle alarm will not clear until a one (1) hour period has passed with less than ten
(10) compressor starts.
POWER PROBLEM or RESTART MODE
The Power Problem or Restart Mode is programmable (See Menu K – Alarms and Limits). There
are three available selections:
1. “Auto, No Alarm” (Automatic: No Message or Alarm). The unit will automatically start after a
power failure or reset. No audio alarm will sound. No message will be displayed on the display
module.
2. “Auto, With Alrm” (Automatic: Message, Audio Alarm & Relay). The unit will automatically re-
start after a power failure or reset. The audio alarm will be activated and the message “ Power
Failure Restart” will be displayed on the display module.
3. “Man, Clr Alarm” (Manual: Message, Audio Alarm & Relay). The unit will NOT automatically
restart after a power failure or restart.
FAN FAILURE ALARM IN CHILLED WATER SYSTEM
Chilled water unit with dap4 controller and plug fans currently has eight different fan speed control
modes. Each mode is modified to add the following fan speed control logic when a Fan Failure
alarm is detected. Fan failure alarm will be detected by fan alarm contact; this sends an alarm
signal to digital input DI12 of the dap4.
When a Fan Failure alarm is detected, the fan speed will automatically ramp up to 100%. If dap4
is programmed to constant speed mode or to maximum speed if dap4 is programmed to other
fan speed control modes. While the Fan failure alarm is active, the audio alarm will sound and an
alarm message “Fan Fails, Check fans” display on dap4 LCD screen. The reheat and humidifier
will be inhibited during fan failure alarm but the chilled water valve will continue to operate. The
fan speed control should automatically go back to the normal operation mode when fan failure no
longer exists.
Note: This logic does not affect any menu settings
