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UNIT ON/OFF SWITCH, SYSTEM SWITCHES
FIG. 35 – UNIT ON/OFF SWITCH
UNIT ON/OFF SWITCH
A master UNIT ON/OFF switch is located on the keypad.
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:
U N I T
S W I T C H
T H E
O F F
P O S I T I O N
SYSTEM SWITCHES
SYSTEM SWITCHES 1 - 4 are located on the
Microprocessor Board (See Fig. 36). 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 the right) for the system to operate.
Whenever a switch is placed in the OFF position, a
STATUS message is displayed indicating that the
YORK INTERNATIONAL
AND OTHER CONTROLS
I S
I N
system does not have a Run Permissive signal. An
example of this message is shown below:
S Y S
1
S Y S
S Y S
2
S Y S
NOTE: This message will not appear if the Anti-recycle
or Anti-coincident timers are in effect and are
being displayed.
ALARM CONTACTS (ANNUNCIATION ALARM)
"Dry" contacts connected to terminals 23 and 24 of TB1
(Fig. 37) are supplied which will transition to function as
a warning whenever a fault lock-out 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.
When a fault occurs or power is lost, the contacts open.
A 28VDC or 120VAC external alarm circuit (supplied by
others) may be wired into the YORK supplied alarm
contacts. Any inductive load devices (relay or contactor)
supplied by the user, which are connected to the dry alarm
FORM 201.10-NM1
UNIT
ON / OFF
SWITCH
28164A
S W I T C H
O F F
S W I T C H
O F F
125
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