Heatcraft Refrigeration Products BEACON II H-IM-79E - Manual (Page 17)

17
Electric Defrost Mode
When a defrost is initiated, the EEV closes, the
compressor is allowed to pumpdown and shut off. The
evaporator fans are cycled off and the defrost heaters
are energized.
On multiple evaporator systems, all controllers must
terminate their defrost, either on temperature or fail-safe
time, before the master controller will end the defrost
cycle.
There is a 2 minute condensate drain-down period after
which the compressor is started for a refreeze period.
The evaporator fan stays off (fan delay). The refreeze
period will last until the evaporator suction temperature
is at 28°F or 3 minutes has elapsed. After this sequence,
the system is back in the refrigerating mode and
evaporators fans are now running.
Air Defrost Mode
The sequence is the same as for electric defrost except
that there are no heaters and the evaporator fans run
continuously. If the air defrost for motors are wired
through the fan relay on the board, they will remain
energized during defrost mode.
Alarms
Beacon II provides a set of dry contacts for use in
signaling an alarm. These contacts can be connected
to a light, a buzzer, a bell etc., which will be activated
when an alarm condition occurs. When the Beacon II is
energized, the alarm contacts are OPENED. When an
alarm condition is detected, the contacts are CLOSED.
Conditions under which the alarm contacts will close are:
• High Box Temperature – LED Display:
A 1 - Room temperature has exceeded
the Alarm High ALH value for the Alarm
time ALt, programmed.
Defrost / Alarms
Clearing Alarms
Alarms A1 – High Box Temperature and A2 – Low
Box Temperature will clear automatically if the Box
Temperature decreases or increases to below or above
the Alarm setpoint temperature. Placing the system in
the
“SERVICE MODE” or turning off power will clear the
A3 Alarm. Replacing the Room Sensor, Suction Sensor
or Pressure Transducer will clear the A4 Alarm.
• Low Box Temperature - LED Display:
A 2 - Room temperature has dropped
below the Alarm Low ALL value for the
Alarm time ALt, programmed
• System Start-up failure – LED Display:
A 3 - Compressor pumps down and tries
to restart after 4 minutes. After 4
unsuccessful attempts to restart, the
alarm code A 3 is displayed. System
continues trying to restart.
• Input Fault – LED Display: A 4 - Box
Temp., Suction Temp., Pressure
Transducer open or not installed.
• Power failure – Loss of power to the
Evaporator
Alarm Codes
A 1 High Box Temp
A 2 Low Box temp
A 3 System Start-up failure
Compressor pumps down and tries to
restart after 4 minutes
A 4 Input Fault
Box Temp., Suction Temp., Pressure
Transducer open or not installed
Power Failure