FORM 201.25-NM1 (302)
25
YORK INTERNATIONAL
Chilled Liquid Pump (CLP)
Terminals 5 and 6 (XVFT) close to start the chilled
liquid pump. These terminals can be used as a master
start/stop for the pump in conjunction with the daily start/
stop schedule. If no schedule is set, and the customer
has master control of the pump, the terminals must be
used to override the customer master start/stop so that
the unit can start the pump in the event of a low liquid
temperature condition.
Common Run Signal (CRS)
Terminals 3 and 4 close to indicate that a system is
running. These terminals may be used to start the cool-
ing liquid pump(s) for the condenser.
System Alarm (SA)
Terminals 1 and 8 (system 1) and 1 and 7 (system 2)
close to indicate an alarm condition whenever a system
locks out, or there is a power failure.
CONTROL PANEL WIRING
All wiring to the control panel terminal block (XTB1)
(nominal 30VDC) must be run in screened cable, with
the screen earthed at the panel end only. Run screened
cable separately from mains cable to avoid electrical
noise pick-up.
The voltage free contacts connected to XTB1 must be
suitable for 30VDC (gold contacts recommended). If
the voltage free contacts form part of a relay or contactor,
the coil of the device must be suppressed using a stan-
dard R/C suppressor. The above precautions must be
taken to avoid electrical noise which could cause a mal-
function or damage to the unit and its controls.
The length of cable to these terminals
must not exceed 24 ft. (7.5 m).
Flow Switch (SF)
A chilled liquid flow switch of suitable type must be
connected to terminals 24 and 13 to provide adequate
protection against loss of liquid flow.
Control Transformer Primary Voltage Tappings
It is important to check that the correct primary tapping
has been used on the control transformer:
• With the supply to the unit isolated remove the lid to
the transformer box.
• Check that the tapping used conforms to the site
supply voltage. The two tappings are 342-424V and
360-440V.
Remote Emergency Stop Device (QRRSB)
A remote emergency stop device may be wired into
the unit. This device should be rated at 8 amps, 230V,
AC-15 and is protected by a maximum fuse size of 8
amps class gG.
The emergency stop device should be wired into termi-
nals 3 and 4 of the door interlocked emergency stop
device located in the common input section after re-
moving the link.
COMMON INPUT SECTION WIRING
All wiring to the customer relay board (ACRB) volt
free contacts (XVFT) require a supply, maximum 254V,
provided by the customer. The customer must take par-
ticular care deriving the supplies for the volt free termi-
nals with regard to a common point of isolation. These
circuits when used must be fed via the common point
of isolation so that the voltage is removed when the
common point of isolation to the unit is opened.
In accordance with National Electri-
cal Code (N.E.C.) it is recommended
that the customer wiring to these ter-
minals uses orange wires. This will
ensure that circuits not switched off
by the supply disconnecting device are
distinguished by color so that they can
easily be identified as live even when
the disconnecting device is off.
The volt-free contacts are rated at 125VA. All inductive
devices (relays) switched by the volt-free contacts must
have their coil suppressed using standard R/C suppressors.
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