York YK-EP B Operation & Maintenance Manual page 174

SECTION 3 - DISPLAY MESSAGES
shutdown is performed and this message is displayed.
This is generally indicative of a wiring problem be-
tween the Control Center and the VSD.
VSD – Serial Communications
This message is generated when communications be-
tween the Control Center Microboard and the VSD
Logic Board is disrupted. This is generally indicative
of defective wiring.
Harmonic Filter – Logic Board or
Communications
This message is generated when communications be-
tween the Harmonic Filter and the VSD Logic Board
is disrupted. The communications must be interrupted
for 10 continuous communications cycles (20 seconds)
before the shutdown will occur.
Harmonic Filter – High DC Bus Voltage
The Harmonic Filter's DC Link Voltage is continu-
ously monitored and if the level exceeds 860VDC,
this shutdown is performed. The Harmonic Filter has
its own DC bus as part of the filter power assembly,
and this DC Link is not connected in any way with
the VSD's DC link. If this shutdown occurs, it will be
necessary to look at the level of 460VAC applied to the
Harmonic Filter. The specified voltage range is 414 to
508. If the incoming voltage is in excess of 508, steps
should be taken to reduce the level to within specified
limits. The cause of this message is typically high line
voltage or a surge on the utility supply.
Harmonic Filter – High Phase A Current
The maximum instantaneous Harmonic Filter current
is monitored and compared to a preset limit. If this
limit is exceeded, a shutdown is performed and this
message is generated. The filter current is monitored
using two DCCT's and these signals are processed by
the Filter Logic Board. The preset limits are as follows:
• 351/292 HP equals 356 Amps
• 503/419 HP equals 496 Amps
• 790/658 HP equals 745 Amps
• 1048/917 HP equals 385 Amps
If the VSD automatically restarts after this shutdown
and continues to operate properly with the filter oper-
ating, it is likely the filter tripped due to a sag or surge
in the voltage feeding the VSD. If this message reoc-
curs, preventing the chiller from starting, the VSD will
require service.
174
Harmonic Filter – High Phase B Current
See Harmonic Filter – High Phase A Current message
above.
Harmonic Filter – High Phase C Current
See Harmonic Filter – High Phase A Current message
above.
Harmonic Filter – Phase Locked Loop
This shutdown indicates that a circuit called Phase
Locked Loop on the Filter Logic Board has lost syn-
chronization with the incoming power line. This is
usually indicative of an open fuse in one of the filter's
incoming power line. Filter power fuses 11FU, 12FU
and 13FU should be checked.
Harmonic Filter – Precharge – Low DC Bus
Voltage
During pre-charge, the Filter's DC link must be equal
to or greater than 50VDC (41VDC for 50 Hz) within
1/10 second after the pre-charge relay is energized. If
this condition is not met, a shutdown is performed and
this message is generated.
VSD – Harmonic Filter-Precharge-Low DC
Bus Voltage
(575V/60 Hz applications)
If the DC Link Voltage does not reach at least 60VDC
(within 100 milliseconds) or at least 630VDC (within
5 seconds) after the filter precharge command has been
received, this shutdown is performed.
Harmonic Filter – Low DC Bus Voltage
The Harmonic Filter generates its own Filter DC link
Voltage by switching its IGBT's. This DC level is ac-
tually higher than the level that one could obtain by
simply rectifying the input line voltage. Thus, the
Harmonic Filter actually performs a voltage BOOST
function. This is necessary in order to permit current to
flow into the power line from the filter when the input
line is at its peak level. This shutdown occurs when the
Filter's DC Link Voltage decreases to a level less than
60VDC below the Filter DC Link Voltage setpoint.
This Setpoint is determined by the Filter Logic Board
via the sensing of the three phase input line-to-line
voltage. This setpoint is set to the peak of the sensed
input line-to-line voltage plus 32 volts, not to exceed
760 volts and it varies with the input line-to-line volt-
age. If this shutdown occurs occasionally, the likely
cause is a severe sag in the input line voltage.
FORM 160.87-OM1
ISSUE DATE: 8/24/2018
JOHNSON CONTROLS