Leaving Condenser Liquid Temperature (Heat Pump Mode) - Johnson Controls YORK OPTIVIEW YK Series Service Instructions Manual

FORM 160.54-M1
For example, if the input is 8mA, and the Remote Reset
Temperature Range setpoint is programmed for 10°F
and the Local Leaving Chilled Liquid Temperature
setpoint is programmed for 40°F, the setpoint would be
set to 42.5°F as follows:
Offset (°F) = (8–4)(10)
16
= (4)(10)
16
= 40
16
= 2.5°F
Setpoint (°F) = 40 + 2.5
= 42.5
PWM
The Pulse Width Modulation input is in the form of a 1
to 11 second relay contact closure that applies 115VAC
to the I/O Board TB4-19 for 1 to 11 seconds. As shown
in Figure 26 on Page 76, connect dry closure relay
contacts between I/O Board TB4-19 (input) and TB4-1
(115VAC). A contact closure time (pulse width) of 1
second produces a 0°F offset. An 11 second closure
produces the maximum allowed offset above the Local
Setpoint value (as allowed by the Remote Reset Tem-
perature Range setpoint). The relay contacts should
close for 1 to 11 seconds at least once every 30 minutes
to maintain the setpoint to the desired value. If a 1 to
11 second closure is not received within 30 minutes
of the last closure, the setpoint is defaulted to the Lo-
cal setpoint value. A closure is only accepted at rates
not to exceed once every 70 seconds. This input will
only be accepted in Digital Remote Mode. Calculate
the setpoint for various pulse widths as follows:
Offset (°F) =
(pulse width in seconds – 1)(Remote Reset Temp Range)
10
Setpoint (°F) = Local Setpoint + Offset
For example, if the relay contacts close for 5 seconds
and the Remote Reset Temperature Range setpoint is
programmed to 10°F and the Local Leaving Chilled
Liquid Temperature setpoint is programmed for 40°F,
the setpoint would be set to 44°F as follows:
JOHNSON CONTROLS
SECTION 21 - REMOTE SETPOINTS
Offset (°F) = (5 – 1)(10)
= (4)(10)
= 40
= 4°F
Setpoint (°F) = 40 + 4
= 44°F
RS-232
As shown in Figure 14 on Page 44, a setpoint can be
received in serial data form at the microboard COM 4B
serial port (J2) from the E-Link Gateway.
LEAVING CONDENSER LIQUID TEMPERATURE
(HEAT PUMP MODE)
(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 using
the Heat Pump Operational setpoint. In Cooling Mode,
the chiller controls the Leaving Chilled Liquid to the
leaving Chilled Liquid Temperature setpoint. In Heat-
ing Mode, the chiller controls the Leaving Condenser
Liquid Temperature to the Leaving Condenser Liq-
uid Temperature setpoint. These two setpoints share a
single remote input that resets the appropriate setpoint
based on the Heat Pump Operational Mode. When in
Cooling Mode, the signal on this input sets the Leaving
Chilled Liquid Temperature setpoint. When in Heating
Mode, this signal sets the Leaving Condenser Liquid
Temperature setpoint.
The Cooling Mode remote reset of the Leaving Chilled
Liquid Temperature setpoint is explained under "Leav-
ing Chilled Liquid Temperature" above.
The Heating Mode remote reset of the Leaving Con-
denser Liquid Temperature setpoint can be accom-
plished by supplying (by others) a 0 to 10VDC, 2
to 10 VDC, 0 to 20mA, 4 to 20mA or a Pulse Width
modulated (PWM) signal to the same inputs as used
for the Leaving Chilled Liquid Temperature setpoint
inputs as explained above. The Leaving Condenser
10
10
10
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