Heatcraft Refrigeration Products II - Manual (Page 22)

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Beacon II Controller
Service Mode
A single pole, single throw switch (SPST) is supplied in each condensing unit for shutting off the system.
Closing the “Service” switch in the condensing unit will cause the system to pumpdown and shut off. “Ser” will
be displayed on the Beacon board LED and “SERVIC” is displayed on the Smart Controller LCD display. The
evaporator fan and heaters will be de-eneergized in the Service Mode.
The system will not restart until the
SPST switch is placed in the “NORMAL” or “OFF” position.
or
The system can be pumped down by pressing the “SERVICE” button twice. To restart the system, press the
“CLEAR” button.
or
The system can be pumped down for service by closing the liquid line service valve in the condensing unit,
then closing the suction line service valve when the system trips on the low pressure switch.
Defrost
DEFROST TIMING
When power is first applied to the system, its timer starts counting time. If 4 defrosts are programmed, it will
initiate a defrost every 6 hours from when power was first applied. Beacon II does not have a real time clock.
Beacon II does provide the ability to delay the starting of the first defrost.
DEFROST DELAY START TIME
Example: The system is first powered up at 8:00 AM and is programmed for 4 defrosts per day. The user
would like the first defrost at 10:00 AM. To accomplish this, use the
“PROGRAM REVIEW” button to scroll to
dFS . Use the “SELECTOR” switch to select 2 hours delay start, then press “ENTER” . The first defrost will
now occur at 10:00 AM and then a defrost will occur every 6 hours thereafter.
DEFROST SCHEDULE IN MEMORY
Beacon II does not have a real time clock but it keeps track of the time that has elapsed in its memory. It also
keeps in memory the number of defrosts scheduled and how much time has elapsed between defrosts. If a
power failure occurs, when power is restored Beacon II will remember how many defrosts are scheduled and
it will remember how much time was left until the next defrost. It will then defrost based on this timing. So, if
the power failure lasted 15 minutes, the defrost schedule will be off by 15 minutes.
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.
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 2 minutes has elapsed. After this sequence, the system is back in the refrigerating mode and the
evaporators’ fans are not 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.