Safety Shutdown Messages - York YK-EP B Operation & Maintenance Manual

FORM 160.87-OM1
ISSUE DATE: 8/24/2018
Harmonic Filter – DC Bus Voltage Imbalance
The Filter DC link is filtered by large, electrolytic ca-
pacitors, rated for 450VDC. These capacitors are wired
in series to achieve a 900VDC capability for the DC
link. It is important the voltage is shared equally from
the junction of the center or series capacitor connec-
tion, to the negative bus and to the positive bus. This
center point should be approximately ½ of the total DC
Link Voltage.
VSD – Harmonic Filter-DC Bus Voltage
Imbalance
(575V/60 Hz applications)
If the Half DC Link Voltage does not remain within
plus or minus 63VDC of the DC Link Voltage divided
by 2, this shutdown is performed.
Harmonic Filter – Input Current Overload
The three phases of RMS Filter current are monitored.
If any one of the three phases continuously exceeds a
given threshold for 7 seconds, a chiller shutdown is
performed and this message is displayed. The maxi-
mum permissible continuous RMS current ratings for
the Harmonic Filter are:
• 351/292 HP equals 128 Amps
• 503/419 HP equals 176 Amps
• 790/658 HP equals 277 Amps
• 1048/917 HP equals 385 Amps
Harmonic Filter – Logic Board Power Supply
The low voltage power supplies on the Filter Logic
Board have decreased below their permissible operat-
ing range. The Filter Logic Board receives its power
from the VSD Logic Board via the ribbon cable, con-
necting the two boards.
Harmonic Filter – Run Signal
When a digital run command is received at the Filter
Logic Board from the VSD Logic Board via the 16 po-
sition ribbon cable, a 1/10 second timer is started. If a
redundant run command does not occur on the serial
data link from the VSD Logic Board before the timer
expires, a shutdown is performed and this message is
generated.
Harmonic Filter – DC Current Transformer 1
During initialization, with no current flowing through
the DC Current Transformers (DCCT's), the DCCT
output voltages are measured and compared with a
JOHNSON CONTROLS
SECTION 3 - DISPLAY MESSAGES
preset limit via the Filter Logic Board. If the measured
values exceed the preset limits, the DCCT's are pre-
sumed to be defective and this shutdown is generated.
Harmonic Filter – DC Current Transformer 2
See Harmonic Filter – DC Current Transformer 1 mes-
sage above.

SAFETY SHUTDOWN MESSAGES

Evaporator – Low Pressure
The Evaporator Pressure, as sensed by the Evapora-
tor transducer, has decreased to the safety shutdown
threshold. For water cooling applications, the safety
shutdown threshold is a fixed value for the respective
refrigerant. For Brine cooling applications, the safety
shutdown threshold varies according to the concentra-
tion of the Brine solution. The Brine shutdown thresh-
old is programmed at the YORK Factory. It should not
be changed by anyone other than a qualified Service
Technician following instructions in OptiView Con-
trol Center – Service Instructions (Form 160.54-M1).
The chiller can be started after the Evaporator Pressure
increases to the restart threshold and the Compressor
Switch is placed in the Stop-Reset (O) position.
SHUTDOWN
Water Cooling - R22
- R134a
Brine Cooling - R22
as programmed
- R134a
as programmed
Evaporator – Low Pressure - Smart Freeze
Smart Freeze protection is activated and has shutdown
the chiller because the evaporator temperature has been
below the Smart Freeze threshold for greater than the
allowable number of seconds. If the Evaporator Refrig-
erant Temperature sensor RT7 is enabled, (using pro-
cedure in OptiView Control Center – Service Instruc-
tions (Form 160.54-M1)), this parameter is used as the
Evaporator Refrigerant Temperature and the freeze
threshold is 32.8°F. If RT7 is not enabled, the Evapo-
rator Refrigerant Temperature used is the Evaporator
Saturation Temperature, derived from the Evaporator
Pressure transducer and the freeze threshold is 34.0°F.
RESTART
(PSIG) (PSIG)
54.3 54.4
25.0 25.1
+0.1 more
25.0 to 54.3 than
Shutdown
threshold
+0.1 more
than
6.0 to 25.0
Shutdown
threshold
175
3