York YCAV0569, Installation Operation & Maintenance

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162
JOHNSON CONTROLS
FORM 201.21-NM2 (616)
REMOTE CURRENT LIMIT RESET CONTROL
Remote Current Limit Reset
Remote Current Limit Reset is used to reset the actual
current limit setpoint used in current limit control. There
are several ways to change the current limit setpoint.
The first is by reprogramming the Local Current Limit
Setpoint under the PROGRAM key. This is the value
the unit will control the current limit to if neither of the
other methods is active.
Remote Current Limit Reset is only possible if the op-
tion is enabled by both the OPTIONS Key selection
and in the factory programmable password protected
Unit Setup Mode.
Remote ISN Current Limit Setpoint
The ISN Current Limit Setpoint can be set via the ISN
comms. The control panel will only accept a Current
Limit Setpoint from the ISN if the control panel is in Re-
mote Control Mode (under the OPTIONS KEY). If the
control panel is in Local Control Mode, the ISN setpoint
will be ignored. The minimum and maximum allowable
values will be the same as the minimum and maximum
allowable reset values for the Current Limit Setpoint
under the PROGRAM key. If these values are exceeded,
the minimum or maximum value will be used.
Contact a local YORK ISN Representative for details
on ISN controls and capabilities.
Remote Current Limit Reset
The Current Limit Setpoint can be set reset via the
Remote Current Limit analog input. A zero signal
input (0% input) equates to the maximum current limit
setpoint as defined under the PROGRAM key Current
Limit Setpoint. A full scale signal input (100% input)
equates to the minimum current limit setpoint as defined
under the PROGRAM key Current Limit Setpoint. The
current limit value is linear and may be adjusted any-
where between the maximum and minimum points of 0
(no offset) and 100% (max. current limiting).
This input may be used either in Local or Remote Con-
trol Mode. This input will be ignored if the Remote
Current Limit is disabled under the OPTIONS key. Once
a change to the input is registered, a timer is set to the
value of the Remote Inputs Service Time as program-
mable under the Unit Setup Mode at the factory for the
default value of 15 minutes. The low limit is 5 minutes
and the high limit is 60 minutes. The Remote input will
be ignored until this timer expires. The timer assures
that rapid changes in a remote reset signal don’t result
in poor temperature control or excessive compressor
cycling. In most instances, this timer will not need to
be changed, since reset more often than 15 minutes will
create problems with chilled liquid temperature control.
Factory Service should be contacted if a timer change
is required.
Control board jumper JP5 must be positioned correctly
to receive either a voltage (0-10VDC or 2-10VDC) or
current (0-20mA or 4-20mA) signal. Place the jumper
in the “V” position for a voltage signal or mA for a
current signal (See FIG. 14, P106). The software must
be configured under the OPTIONS key for the type of
input signal to be used.
The minimum current limit setpoint is achieved at either
10 VDC or 20 mA. Sending the minimum signal (0
VDC, 2 VDC, 0 mA, or 4 mA based on the OPTIONS
key setting) causes the current limit to revert back to its
maximum value.
OPERATION