York YK Style H Operation Manual page 177

FORM 160.76-O2
issue date: 6/15/2015
• Plugged Heat-exchanger – In cases where the
strainer plugs frequently, the heat-exchanger may
eventually plug or become restricted to the point
of reduced flow. At this point, we suggest you
back-flush the heat-exchanger by reversing the
two rubber hoses which supply condenser water
to-from the heat-exchanger. If the rust cannot be
back-flushed, the heat-exchanger might have to be
replaced.
• Low Condenser Flow – The VSD system requires
8 feet of pressure drop across the heat exchanger
to maintain adequate GPM. If the pressure drop is
less than 8 feet, it will be necessary to correct the
flow problem or add a booster pump as is applied
on retrofit chillers.
VSD – Invalid Current Scale Selection
Since the part number of the VSD Logic Board is the
same on all horsepower sizes, the position of Program
Jumpers tells the Logic Board the size of the VSD
employed. This allows the VSD to properly scale the
output current. If the jumper configuration is invalid, a
shutdown is performed and this message is generated.
Refer to Variable Speed Drive – Service Instructions
(Form 160.00-M1).
VSD – Low Phase A Inverter Heatsink
Temperature
(Style D VSD)
A heatsink temperature sensor indicating a temperature
less than 37°F will cause the chiller to shut down and
display this message. In most cases, the problem will
be an open transmitter or broken wiring to the transmit-
ter. The normal transmitter resistance is 10K ohms at
77°F.
VSD – Low Phase B Inverter Heatsink
Temperature
(Style D VSD)
See Low Phase A Inverter Heatsink Temperature mes-
sage above.
VSD – Low Phase C Inverter Heatsink
Temperature
(Style D VSD)
See Low Phase A Inverter Heatsink Temperature mes-
sage above.
JOHNSON CONTROLS
SECTION 3 - DISPLAY MESSAGES
VSD – Low Converter Heatsink Temperature
If VSD part number is 371-02767-XXX (60Hz) or 371-
03700-XXX (50Hz), a heatsink temperature sensor in-
dicating a temperature of less than 37°F will cause the
chiller to shutdown and display this message. In most
cases, the problem will be an open transmitter or bro-
ken wiring to the transmitter. The normal transmitter
resistance is 10K ohms at 77°F.
VSD – Low Phase A Inverter Baseplate
Temperature
(VSD part number 371-03789-xxx (503 HP 60Hz; 419
HP 50Hz)
The chiller has shutdown because the baseplate tem-
perature has decreased to less than 37°F.
VSD – Low Phase B Inverter Baseplate
Temperature
(VSD part number 371-03789-xxx (503 HP 60Hz; 419
HP 50Hz)
The chiller has shutdown because the baseplate tem-
perature has decreased to less than 37°F.
VSD – Low Phase C Inverter Baseplate
Temperature
(VSD part number 371-03789-xxx (503 HP 60Hz; 419
HP 50Hz)
The chiller has shutdown because the baseplate tem-
perature has decreased to less than 37°F.
VSD – Precharge – Low DC Bus Voltage
During pre-charge, the DC link must be equal to or great-
er than 50VDC (41VDC for 50Hz) within ½ second and
500VDC within 15 seconds after the pre-charge relay is
energized. If this condition is not met, a shutdown is per-
formed and this message is generated.
VSD – Precharge – Low DC Bus Voltage
(575V/60Hz applications)
If the DC Link Voltage does not reach at least 60VDC
(within 4 seconds) or at least 600VDC (within 20 sec-
onds) after the precharge command has been received,
this shutdown is performed.
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