Johnson Controls YORK YK MaxE, Operation Manual

Page: 155 / 184

FORM 160.54-O1
155
JOHNSON CONTROLS
2
“ VSD – HIgH InTERnAL AMBIEnT
TEMPERATURE
”
The ambient temperature monitored is actually the
temperature detected by a component mounted on the
VSD logic board. The high ambient trip threshold is set
for 140°F. Some potential causes for this shutdown are:
internal VSD fan failure, VSD water pump failure or an
entering condenser water temperature that exceeds the
allowable limit for the job. Additional causes for the
shutdown are:
•
Plugged Strainer – The standard 1.5” Y-strainer
contains a woven mesh element with 20 stainless
steel wires per inch. This has been found to work ad-
equately on most applications. Some users may have
very dirty condenser water, which can cause the
strainer to plug. Locations with special conditions
may want to consider a dual strainer arrangement
with quarter turn valves, to permit cleaning of one
strainer with the unit still on line.
•
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 YORK VSD Service manual 160.00-M1.
“ VSD – LOW PHASE A InVERTER HEATSInK
TEMPERATURE ”
(Style D VSD)
A Heatsink temperature sensor indicating a temperature
<37°F will cause the chiller to shut down and display
this message. In most cases, the problem will be an
open thermistor or broken wiring to the thermistor. The
normal thermistor resistance is 10K ohms at 77°F.
“ VSD – LOW PHASE B InVERTER HEATSInK
TEMPERATURE
”
(Style D VSD)
See “Low Phase A Inverter Heatsink Temperature”
message above.
“
VSD – LOW PHASE C InVERTER HEATSInK
TEMPERATURE ”
(Style D VSD)
See “Low Phase A Inverter Heatsink Temperature”
message above.
“ VSD – LOW COnVERTER HEATSInK TEM-
PERATURE”
If VSD part number is 371-02767-XXX (60 Hz) or
371-03700-XXX (50 Hz), a heatsink temperature sen-
sor indicating 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 thermistor or
broken wiring to the thermistor. The normal thermistor
resistance is 10K ohms at 77°F.
“VSD – LOW PHASE A InVERTER BASEPLATE
TEMPERATURE”
(VSD part number 371-03789-xxx (503 HP 60 Hz; 419
HP 50 Hz) (Flash Memory Card version C.MLM.01.08
and later)
The chiller has shutdown because the Baseplate tem-
perature has decreased to less than 37 ºF.
“VSD – LOW PHASE B InVERTER BASEPLATE
TEMPERATURE”
(VSD part number 371-03789-xxx (503 HP 60 Hz; 419
HP 50 Hz) (Flash Memory Card version C.MLM.01.08
and later)
The chiller has shutdown because the Baseplate tem-
perature has decreased to less than 37 ºF.
“VSD – LOW PHASE C InVERTER BASEPLATE
TEMPERATURE”
(VSD part number 371-03789-xxx (503 HP 60 Hz; 419
HP 50 Hz) (Flash Memory Card version C.MLM.01.08
and later)
The chiller has shutdown because the Baseplate tem-
perature has decreased to less than 37 ºF.
“
VSD – PRECHARgE – LOW DC BUS
VOLTAgE ”
During Pre-charge, the DC link must be equal to or
greater than 50VDC (41VDC for 50 Hz) within ½ second
and 500VDC within 15 seconds after the Pre-charge re-
lay is energized. If this condition is not met, a shutdown
is performed and this message is generated.