York YCAZ33BA3, Руководство пользователя, Страница: 63 / 88

FORM 150.44-NM4
63
YORK INTERNATIONAL
on the Microprocessor of the lead compressor is placed
in the OFF position.
The “dry” contact for manual lead/lag selection is wired
into terminals 13 and 19. The location of these con-
tacts is shown below in Fig. 23.
FIG. 23 – LEAD/LAG CONTACT CONNECTION
LOCATION
MEMORY BATTERY BACK-UP
The Microprocessor board contains a Real Time Clock
(RTC) I.C. Chip with an internal battery back-up. The
battery back-up assures that any programmed values,
clock, all fault information, accumulated information
such as starts/run time, etc. stored in the RTC memory
is not lost when a powerfailure occurs regardless of
the time period.
The battery is a 10-year lithium type. The life of the
battery with power removed will depend upon whether
the Real Time Clock’s internal clock circuit is energized.
With the clock OFF, approximately 10 years can be
expected, with the clock ON, approximately 5 years.
The clock is turned ON and OFF by a jumper on the
Microprocessor Board. While a chiller is operating, the
clock must be ON. Otherwise the internal clock on the
microprocessor will not be active and the micro cannot
keep track of time, although all other functions will op-
erate normally. This could result in the chiller not start-
ing due to the time frozen on the clock falling outside
the START/STOP time window that is programmed in
the DAILY SCHEDULE.
If the chiller is shut-down for extended periods of
months, it may be desirable to disable the clock to save
battery life. The clock can then be reactivated and re-
programmed when the chiller is returned to service.
NOTE: ALL PROGRAMMED VALUES AND STORED
DATA, OTHER THAN THE INTERNAL CLOCK
TIME-KEEPING, WILL BE MAINTAINED IN
MEMORY REGARDLESS OF WHETHER THE
CLOCK IS ON OR OFF AND REGARDLESS
OF THE LENGTH OF THE POWER FAILURE.
To disable the clock, place the jumper (Fig. 24) in the
OFF positions. To activate it, place the jumper in the
ON position.
On power-up, the microprocessor will check the Real
Time Clock (RTC Chip) battery to assure that the inter-
nal battery is still operational. This is accomplished by
performing an RTC RAM location check. As long as
the battery checks out, the microprocessor will con-
tinue on with business without interruption.
If a check is made and the battery has failed, the mi-
croprocessor will not allow the chiller to run and the
following STATUS message will appear:
The only way to run the chiller is to press the MANUAL
OVERRIDE key. Under low battery conditions, the man-
ual override key will function differently than it normally
does in service situations where it overrides the daily
schedule for only 30 min. In a low battery condition,
the MANUAL OVERRIDE key will zero out the daily
schedule to allow unlimited operation regardless of the
time on the internal clock. Default values will also be
loaded into memory for all setpoints and cut-outs. These
may require reprogramming to assure they meet chiller
LD02005
26001A
FIG. 24 – CLOCK JUMPER
CLOCK JUMPER
! ! W A R N I N G ! !
! ! L O W B A T T E R Y ! !