The Cold Leaving Liquid Temperature Set Point and
Range (cooling) are used to ensure that whilst the
capacity step of the systems/compressors is set to meet
the heating demand too low a cold liquid temperature
will first prevent further loading, leaving liquid cold
temperature in cooling range, and if necessary unload
the systems/compressors, if leaving liquid cold
temperature is below cooling range.
The change in unload timing as error increases still
applies as described in the standard chiller section of
the manual. TEMP ERROR in heatpump represents
Leaving Liquid Temperature Hot error not Leaving
Liquid Temperature cold error.
The existing programmed RATE CONTROL TEMP and
RATE SENSITIVITY are common to both cooling and
heatpump modes. There are two rate of change
displayed one for the COLD liquid, one for the HOT
liquid under oper data key.
The setpoint adjust feature (as descried in Section 2)
works as in the cooling mode but the heating setpoint
low limit is lowered by up 10°C to a minimum of 25°C.
Any adjustment value in excess of the value taking the
Setpoint Low Limit to 25°C is added to the Setpoint High
Limit.
15.5 BAS/EMS Temperature Reset - Voltage /
Current Signal
If the EMS-PWM feature has been activated, no
message REMOTE TEMP RESET INPUT is visible
under the OPTION key and the following feature is
disabled. Contact Johnson Controls York Product
service if you require the following feature.
In the heating mode the hot liquid setpoint can be reset
downwards from the manually entered setpoint by using
a remote 0 - 10 Vdc or 2 - 10 Vdc or 0 - 20 ma or a 4 - 20
mA signal connected to terminal block -XTBC1
terminals A- and A+.
Whenever a reset is called for by the remote signal, the
change may be viewed by pressing the 'SETPOINTS'
key four times. The new value will be displayed as 'REM
H SP = XXX °C'. The analogue input is only read for a
fixed interval. This is normally factory set to 5 minutes.
15.5.1 0-10 Vdc Remote Signal
Jumper JP on the I/O board must be set to 10 V.
To calculate the reset hot liquid setpoint for values
between 0 Vdc and 10 Vdc use the following formula:
Setpoint = Local Hot Liquid Setpoint - °C Reset
°C Reset = (DC voltage signal) x *Max Reset Value)
10
Example:
Local Hot Liquid Setpoint = 50.0°C
*Max Reset Value = 10°C
Input Signal = 6 Vdc
°Reset = (6 Vdc x 10. 0 °C) = 6.0 °C Reset
10
New Setpoint = 50.0 °C - 6.0 °C = 44.0 °C
15.5.2 2-10 Vdc Remote Signal
Jumper JP on the I/O board must be set to 10 V.
To calculate the reset hot liquid setpoint for values
between 2 Vdc and 10Vdc use the following formula:
Setpoint = Local Hot Liquid Setpoint - °C Reset
°C Reset = ((DC voltage signal - 2) x *Max Reset Value)
8
Example:
Local Hot Liquid Setpoint = 45.0 °C
*Max Reset Value = 10 °C
Input Signal = 6 Vdc
°C Reset = ((6 Vdc - 2) x 10. 0 °C) = 5.0 °C Reset
8
New Setpoint = 45.0 °C - 5.0 °C = 40.0 °C
15.5.3 0-20 mA Remote Signal
Jumper JP on the I/O board must be set to 20 mA.
To calculate the hot liquid setpoint for values between
0 mA and 20 mA use the following formula:
Setpoint = Local hot Liquid Setpoint - °C Reset
°C Reset = (mA signal x *Max Reset Value)
20
Example:
Local Hot Liquid Setpoint = 50.0 °C
*Max Reset Value = 5.0 °C
1
-
47
Form 201.26.OI1(11/09)
T E M P
R A T E
C O L D
7 . 6
H O T
=
3 . 6 ° C / M I N
