Cycling Shutdowns - York MILLENNIUM YIA-ST-1A1 Operation Manual

After it has been determined that crystallization has not
occurred during the shutdown, the unit can be restarted.
To restart unit, press UNIT switch to STOP/RESET po-
sition, then press the WARNING RESET key in SER-
VICE mode, and then initiate a start.
SUN 12:00 AM HIGH STEAM SUPPLY PRESSURE
(Steam Units Only; not applicable to units equipped with
EPROM version A.02F.02 or later) )
Unit has shut down because the steam supply pressure,
as sensed by Transducer PT2, has increased to 29.0
PSIA (199.9 kPa). The unit will be allowed to restart when
pressure decreases to 28.9 PSIA (199.2 kPa). To restart
unit, press the UNIT switch to STOP/RESET position,
then to START position.
SUN 12:00 AM – MCFL – CHK FOR CRYSTALLIZATION
(Units equipped with Franklin pumps only)
(MCFL = Motor Coolant Float Switch)
This message indicates the unit is prevented from start-
ing because the Strong Solution Temperature (as mea-
sured by Thermistor RT3) decreased to < 136°F (57.7°C)
before the Motor Coolant Float Switch reclosed during a
"Motor Coolant Switch" safety shutdown.
A dilution cycle is not initiated on "Motor Coolant Float
Switch" safety shutdowns until the float switch recloses.
However, if the Strong Solution Temperature has de-
creased to < 136°F (57.7°C) before the switch closes, a
dilution cycle is not initiated because crystallization might
have occurred during the shutdown. This message ad-
vises the operator to check for crystallization prior to
starting the unit.
After it has been determined that crystallization has not
occurred during the shutdown, the unit can be restarted.
To restart unit, press UNIT switch to STOP/RESET po-
sition, then press WARNING RESET key in SERVICE
mode and then initiate a start.
SUN 12:00 AM – PF – CHK FOR CRYSTALLIZATION
(PF = Power Failure)
This message indicates the unit is prevented from start-
ing because a power failure interrupted a dilution cycle
or prevented a dilution cycle from being initiated and
when power was restored, the Strong Solution Tempera-
ture (as measured by Thermistor RT3) was >136°F
(57.7°C).
Since a dilution cycle cannot be performed during a
110
power failure, and the Strong Solution Temperature has
decreased to <136°F (57.7°C) during the power failure,
crystallization might have occurred. This message is ad-
vising the operator to check for crystallization prior to
starting the unit. After it has been determined that crys-
tallization has not occurred, the unit can be started. To
start unit, press UNIT switch to STOP/RESET position,
press WARNING RESET key in SERVICE mode, then
initiate a start.

CYCLING SHUTDOWNS

SUN 12:00 AM COND FLOW SWITCH – AUTO START
Condenser flow switch has opened for 30 consecutive
seconds while unit was running or did not close within
30 seconds of the condenser water pump starting at unit
start. The unit will automatically restart when the flow
switch closes.
SUN 12:00 AM POWER FAILURE – AUTO START
A power failure has occurred with the Control Center
operating in "Auto-Restart After Power Failure Mode"
(Micro Board program jumper J50 in IN). If the unit is
running when the power failure occurs, it will automati-
cally restart when power is restored.
SUN 12:00 AM LOW WATER TEMP – AUTO START
The leaving chilled water temperature has decreased to
2°F (0.5°C) below the LEAVING CHILLED WATER
TEMP set-point. The unit will automatically restart when
the water temperature increases to 2°F (0.5°C) above
the setpoint. If the setpoint is increased while the unit is
running, the shutdown threshold is the previous thresh-
old for 30 minutes to eliminate nuisance trips.
SUN 12:00 AM LVG WATER TEMP < SETPOINT
The unit is shut down for any reason other than
SUN 12:00 AM LOW WATER TEMP – AUTO START
ing chilled water temperature is less than the LEAVING
CHILLED WATER TEMP setpoint. It will be allowed to
start when the water temperature is equal to or greater
than the setpoint. If a start signal is applied while shut-
down with this condition, the unit will automatically start
when the condition clears.
NOTE: This check is not performed if the unit has shut
down on
SUN 12:00 AM LOW WATER TEMP – AUTO START
and the leav-
. If
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