56
YORK INTERNATIONAL
UNIT ON/OFF SWITCH
A master UNIT ON/OFF switch is located on the key-
pad. This rocker switch allows the operator to turn the
entire chiller OFF if desired. The switch must be placed
in the ON position for the chiller to operate.
Whenever the switch is placed in the OFF position, a
STATUS display indicating the condition will be displayed.
This message is shown below:
SYSTEM SWITCHES
SYSTEM SWITCHES 1-4 are located on the Micropro-
cessor Board (See Fig. 21). These allow the operator to
selectively turn a given system on or off as desired. On
a 2 system chiller, switches 3 & 4 should be OFF. The
System Switch for a designated system must be ON
(Switch to right) for the system to operate.
Whenever a switch is placed in the OFF position, a STA-
TUS display indicating the condition will be displayed
indicating that the system does not have a Run Permis-
sive signal. A sample of this message is
shown below:
NOTE: This message will not appear if Anti-recycle or
Anti-coincident timers are in effect and are be-
ing displayed.
ALARM CONTACTS (ANNUNCIATION ALARM)
“Dry” contacts connected to terminals 23 and 24 (Fig. 22)
are supplied, which will transition to function as a warn-
ing whenever a fault shutdown occurs on any system or
if power is lost to the control panel. The dry contacts are
normally open (N.O.) and will close when control power
is applied to the panel, if no fault conditions are present.
If power is lost or a fault lockout occurs, the contact will
open.
A 28VDC or 120VAC external alarm circuit (by others)
may be wired into the YORK supplied alarm contacts.
Any inductive load devices (relay, contactor), supplied
by the user which are connected to the dry contacts,
MUST be suppressed at the load. Use YORK P/N 031-
00808-000 suppressor (not supplied). Failure to do this
will result in nuisance faults and possible damage to the
chiller.
CAUTION: If the alarm circuit is applied in an application
used for critical duty (such as process duty
or cooling other critical equipment) and the
alarm circuit should fail to function, YORK
will not be liable for damages.
MEMORY BATTERY BACK-UP
The Microprocessor board contains a Real Time Clock
(RTC) I.C. Chip with an internal battery back-up. The bat-
tery 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 power failure occurs regardless of the time
period.
U N I T S W I T C H I S I N
T H E O F F P O S I T I O N
“UNIT” ON/OFF SWITCH
S Y S # 1
N O R U N P E R M
S Y S # 2
N O R U N P E R M
26572A(D)
UNIT ON/OFF SWITCH
