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253
FORM 160.54-M1
ISSUE DATE: 10/25/2019
JOHNSON CONTROLS
JCI COMPANY CONFIDENTIAL
31
SECTION 31 - HEAT PUMP DUTY
(SOFTWARE VERSION C.OPT.01.23.307 AND LATER)
Heat Pump is an available option for certain models
of YK chillers. On a Heat Pump equipped chiller,
with Heat Pump Duty enabled, the chiller control can
be switched between Cooling and Heating Mode. In
Cooling Mode, the chiller controls the Leaving Chilled
Liquid to the Leaving Chilled Liquid Temperature
setpoint. In Heating Mode, the chiller controls the
Leaving Condenser Liquid Temperature to the Leaving
Condenser Liquid Temperature setpoint. When Heat
Pump is enabled, certain conditions are automatically
set as described below.
All setpoints pertinent to this feature are maintained on
the HEAT PUMP Screen.
INPUTS/OUTPUTS
Due to the higher temperatures and pressures required
in Heating Mode, the following sensors are changed
from normal operation:
• Leaving Chilled Liquid Temperature Thermistor
– This Thermistor is moved to Microboard jump-
er configurable input connector J7-14. Program
Jumper JP21 must be positioned on pins 2-3. The
new temperature range is 0-136.4°F.
• Entering Chilled Liquid Temperature Thermistor
– This thermistor remains at its normal location,
but the temperature range of this thermistor is in-
creased to 0-133.9°F.
• Evaporator Transducer – Higher range Transducer
025-28678-115 is required. This transducer has a
higher pressure range (0-125 psig).
SETPOINTS
Heat Pump Duty Enable/Disable
If equipped for Heat Pump duty, the feature must be set
to ENABLED on the SETUP Screen using an ADMIN
password, to make the feature operational. The access
level must be ADMIN and the Refrigerant Type must be
set to R-134a (SW1-1) for the setpoint to appear on this
screen. If refrigerant type is changed after Heat Pump
Duty has been enabled, Heat Pump Duty becomes dis-
abled and disappears from the SETUP Screen. When
enabled, the HEAT PUMP Screen is accessible from
the CONDENSER Screen.
Operational Mode
Sets the Heat Pump operation to either COOLING
(default) or HEATING operation. In order to change
this setpoint, the access level must be OPERATOR (or
higher) and the COMPRESSOR switch must be in the
Stop-reset Position.
Heating Sensitivity
Adjusts the sensitivity of the PRV response to changes
in the Leaving Condenser Liquid Temperature in Heat-
ing Mode. Can be set to NORMAL (default), 50%,
30%, 10%. Normal is the standard setting and provides
the longest PRV pulse for a given change. The 50%,
30% and 10% selections provide decreasing pulse du-
rations for the same change in the Leaving Condenser
Liquid Temperature. Select smaller settings, as neces-
sary, to prevent overshoot of the Leaving Condenser
Liquid Temperature setpoint.
Local Leaving Condenser Liquid Temperature
Setpoint
Sets the Local setpoint (entered at the keypad) to which
the Leaving Condenser Liquid Temperature will be
controlled in Heating Mode. Programmable over the
range of 65.0°F to 122.0°F (default 95.0°F). Requires
OPERATOR or higher access level.
Remote Leaving Condenser Liquid
Temperature Setpoint
This setpoint can be set from a remote device as fol-
lows: ISN Mode – setpoint sent via E-Link Gateway
serial communications to COM4B serial port. Digital
Mode – 1-11 second signal that adds offset (over the
range of the Leaving Condenser Liquid Temperature
Range setpoint) to the locally entered value (1S =
0%, 11S equals 100% offset). Analog Mode – 0 to 10
VDC/2 to 10 VDC or 0 to 20mA/4 to 20mA signal that
adds offset (over the range of the Leaving Condenser
Liquid Temperature Range setpoint) to the locally en-
tered value (0V/2V/0mA/4mA equals 0%, 10V/20mA
equals 100% offset).
Leaving Condenser Liquid Temperature
Range
Sets the range over which an analog signal (0 to 20mA,
4 to 20mA, 0 to 10 VDC or 2 to 10 VDC) in Analog Re-
mote Mode or a PWM signal (1-11 seconds) in Digital