Pre-Rotation Vanes Position; I/O Board; Stall Transducer; Stall Detector Board - Johnson Controls YORK OPTIVIEW YK Series Service Instructions Manual

FORM 160.54-M1

PRE-ROTATION VANES POSITION

The Pre-rotation Vanes position, as used by the VGD
control, is provided by a potentiometer mounted to the
PRV control arm. The potentiometer interface varies
according to how the chiller is equipped as follows:
• If the chiller is equipped with a Compressor Mo-
tor Variable Speed Drive, the potentiometer is
connected to either the Adaptive Capacity Control
(ACC) Board or the microboard, depending on
where the ACC function is performed. If the ACC
Board is present, the potentiometer is connected
to the ACC Board J4. In applications where the
ACC functionality is contained in Microboard
031-02430-001 (ACC Board not used), the poten-
tiometer is connected to the microboard J7.
• If the chiller is not equipped with a Variable Speed
Drive, but is equipped with the Hot gas bypass
option, the PRV potentiometer is connected to ei-
ther the Analog I/O Board or Microboard depend-
ing on which I/O Board is present. If Analog I/O
Board 371-02514-000 is present, it is connected
to this board at P1. If I/O Board 031-02895-000 is
present, it is connected to the microboard J7.
• If the chiller has neither a Variable Speed Drive
nor the Hot gas option, the potentiometer is con-
nected directly to the microboard at J7.

I/O BOARD

Chillers equipped with this feature are supplied with
and require I/O Board 031-01743-002. This board is
populated with the required triacs Q3 and Q4 that ap-
ply the open and close signals to the VGD actuator. I/O
Board 031-01743-001 does not contain required triacs
Q3 and Q4.

STALL TRANSDUCER

Detects stall noise as high frequency pressure fluctua-
tions in the discharge scroll of the compressor. It con-
verts the pressure pulsations to DC voltage pulsations
and applies them to the Stall Detector Board. Early
vintage chillers were shipped with Stall Transducer
025-39464-000. Later chillers are shipped with Stall
Transducer 025-40088-000. These transducers require
different wiring connections at the transducer. Check
the part number of the replacement transducer and make
connections at the transducer connector as follows:
JOHNSON CONTROLS
SECTION 25 - VARIABLE GEOMETRY DIFFUSER
Transducer 025-39464-000
pin 1 - signal out - WHT
pin 2 - ground - BLK
pin 3 - +5VDC supply voltage - RED
Transducer 025-40088-000
pin 1 - +5VDC supply voltage - RED
pin 2 - ground - BLK
pin 3 - signal out - WHT

STALL DETECTOR BOARD

The Stall Detector Board (031-02418-000) converts
the Stall Transducer DC voltage pulsations to an analog
DC voltage output (J2-4) that represents the magnitude
of stall noise and applies it to the microboard (J7-23).
This board also provides a path for the Stall Transducer
unprocessed DC voltage pulsations output to be con-
nected from J2-2 to the microboard (J8-1). This output
is used for the Stall Sensor Validation feature.
There are two versions of the Stall Detector Board as
follows:
031-02418-000
Supplied in new production chillers and as replace-
ment part until June 2007.
031-02418-001
Supplied in new production chillers and as replace-
ment part after June 2007. This board contains a filter
that removes the noise associated with high gas flow/
low head conditions and thus prevents VGD closing in
response to conditions that are not true stall conditions.
Shunt jumper JP1 allows operation with or without the
filter. With JP1 in the ENHANCED position (on pins 1
and 2), the filter is engaged. With it in the STANDARD
position (on pins 2 and 3), the filter is not engaged and
would operate the same as the -000 board above. Use
the following guidelines:
• ENHANCED Mode – The board is shipped con-
figured in this mode. In this mode, it filters the
noise associated with high gas flow/low head con-
ditions and thus prevents VGD closing in response
to conditions that are not true stall conditions. The
presence of this filter could require adjustment of
the setpoints as follows: The Stall Detector Board
outputs an analog voltage (displayed as STALL
DETECTOR VOLTAGE on the VGD Screen)
that represents the magnitude of stall noise pres-
25
201