Manual Override Key - York YCAS Series Installation Operation & Maintenance

Air-cooled screw liquid chillers
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If an error is made while programming or a change is
required, press Cancel. This will clear the programmed
(*) "Holiday" days (the "0" key will not cancel out a
" * " and cannot be used for correcting a programming
error).
7.4

MANUAL OVERRIDE KEY

When the Manual Override key is pressed, the Daily
Schedule programmed into the chiller is ignored and
the chiller will start up when water temperature is above
the high limit of the Control Range, the Chiller ON/OFF
switch is ON, remote cycling devices are CLOSED, and
system switches permit.
Normally this key is only used for ser vic ing when the
chiller is required to run, but the Daily Sched ule is in
an OFF period. This key avoids the need to reprogram
the Daily Schedule. Once activated, Manual Over ride is
only active for a period of 30 min utes and the fol low ing
sta tus message will be ob served:
M A N U A L
O V E R R I D E
YORK INTERNATIONAL
FORM 201.19-NM8 (804)
If a Warning – Low Battery fault
mes sage appears on the display, the
in ter nal clock, cal en dar, and pro-
gram set tings cannot be relied on for
accuracy. Default val ues are loaded
into the mi cro pro ces sor mem o ry and
the Man u al Over ride key can be used
to zero out the daily sched ule and al-
low un lim it ed operation re gard less
of the time on the internal clock.
Re pro gram ming of the setpoints and
cut out values may also be nec es sary.
When the MAN U AL OVER RIDE key
is pressed, the low bat tery mes sage will
disappear. If a power fail ure should
again occur, the above pro cess will
again need to be re peat ed to bring the
chill er back on line. See also Section
2.3, page 149.
8
177

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