York MILLENNIUM Manual page 5

mand exists, after five minutes. The chiller will con-
tinue to run until demand shuts it off or until commu-
nication is re-established. When communication re-
turns, the chiller will shut down, honoring the remote
shutdown that was commanded prior to the communi-
cations loss. The ability to do this is built into the chiller
micro, which remembers the setpoints/control com-
mands established before the communications loss.
A LOSS OF COMM LINK TO AC SCREW PANEL
message indicates that the communications link be-
tween the chiller MicroComputer Control Center and
the Remote Control Center has been lost. This loss of
YORK INTERNATIONAL
RCC HARDWARE AND SETUP – CONT'D
communications can be the result of a disconnect in
the communications cable between the two panels; the
loss of power to the chiller control panel; or a faulty
communications driver chip. These driver chips are lo-
cated on the chiller microboard at location U24, and
on the RCC microboard at location U15. On the chiller,
RS-485 and RS-232 driver chips at U24 and U59 re-
spectively, can be interchanged when the RS-232 printer
port is not being utilized. At RCC, board replacement
is required. If communications are lost and not re-estab-
lished after 5 minutes, local chiller setpoints (those pro-
grammed at the chiller panel) will command the chiller.
FORM 201.18-NM1.2
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