Configuration/Setup - York YK-EP B Operation & Maintenance Manual

FORM 160.87-OM1
ISSUE DATE: 8/24/2018
or +5VDC signal. In some displays, the backlight turns
ON when this signal transitions from low to high; oth-
ers turn OFF when it transitions from high to low. The
position of Program Jumper JP3 determines the transi-
tion that will occur when the microboard outputs the
Backlight Enable signal. JP3 must be positioned ac-
cording to the display manufacturer's requirement.
The microboard controls the backlight brightness via
the Lamp Dimmer circuit output at J6-7. In order to
extend the life of fluorescent Backlight lamps, the
brightness is driven to 50% after 10 minutes of Key-
pad inactivity. At this brightness level, the graphics are
still visible. When Keypad activity is detected (a key is
pressed), the lamp is driven back to full (100%) bright-
ness. Some display manufacturers require a variable
voltage to vary the brightness; others require a vari-
able resistance. Program Jumpers JP7 and JP8 must be
configured to enable the appropriate technique. The
Lamp Dimmer is an integrated circuit that is the elec-
trical equivalent of a 10K ohm potentiometer with 100
positions or steps. The Lamp Dimmer controls the po-
sition of the potentiometer. The Lamp Dimmer varies
the brightness of the backlight by applying a variable
voltage (0 to 5.0VDC) or a variable resistance (0 to
10K ohms) to the Backlight Inverter Board (If applica-
ble). If Program Jumpers JP7 and JP8 are installed, the
Lamp Dimmer output is a variable voltage; if both are
removed, the output is a variable resistance. The Lamp
Dimmer outputs "Brightness Control Wiper" (J6-7) to
the Backlight Inverter Board. If configured for variable
voltage output, the voltage between J6-7 and J6-8 can
be varied from 0VDC (100% brightness) to 5.0VDC
(0% brightness). If configured for variable resistance,
the resistance between J6-6 and J6-7 varies from 0
ohms (0% brightness) to 10K ohms (100% brightness).
Remote Setpoints
Remote Leaving Chilled Liquid Temperature and Cur-
rent Limit setpoints can be input via the RS-232 SC-
EQ communications interface at J2 or directly to the
microboard at J22 using a hardwired analog signal.
The inputs at J22 are configured with Program Jump-
ers JP23 and JP24 to accept these inputs in either 0 to
10VDC, 2 to 10VDC, 0 to 20mA or 4 to 20mA form.
JOHNSON CONTROLS

CONFIGURATION/SETUP

The following functions are entered as setpoints on the
SETUP Screen.
Chilled Liquid Pump Operation – Determines
Chilled Liquid Pump control contacts (I/O Board TB2-
44/45) operation when chiller shuts down on cycling
shutdowns. Selections are:
1. Standard – Contacts open at completion of System
Coastdown after all shutdowns except LEAVING
CHILLED LIQUID – LOW TEMPERATURE.
On this shutdown, they remain closed, causing
the pump to continue to run while the chiller is
shutdown.
2. Enhanced – Contacts open at completion of Sys-
tem Coastdown after all shutdowns except LEAV-
ING CHILLED LIQUID – LOW TEMPERA-
TURE, MULTI-UNIT CYCLING – CONTACTS
OPEN and SYSTEM CYCLING – CONTACTS
OPEN. On these shutdowns, they remain closed,
causing the pumps to continue to run while the
chiller is shutdown.
Motor Drive Type – Configures the program for the
applicable Primary compressor motor drive type. Se-
lections are:
1. EM – Electromechanical Starter
2. SSS-Mod A – Style A Solid State Starter
3. SSS-Mod B – Style B Solid State Starter
4. VSD-60Hz – Variable Speed Drive, 60Hz
5. VSD-50Hz – Variable Speed Drive, 50Hz
6. MVVSD – Medium Voltage VSD
7. MVSSS – Medium Voltage Solid State Starter
Anti-recycle – Enables or Disables the Anti-recycle
timer. Selections are:
1. Enabled – Enables the anti-recycle timer. Solid
State Starters and electromechanical starter appli-
cations cannot be started at intervals shorter than
once every 30 minutes. VSD applications can be
started at the completion of System Coastdown
up to 5 times. On the 5th shutdown, a 10-minute
timer is started and restart is inhibited until the
timer has elapsed.
2. Disabled – Disables the anti-recycle timer. Chill-
er can be started at the completion of System
Coastdown, regardless of how long the chiller had
been running.
SECTION 5 - SERVICE
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