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72
Recommended Applications — This control scheme is rec-
ommended for constant volume applications and is compatible
with both standard and digital compressor operation. Minimum
Load Control is supported by this control scheme; however,
Minimum Load Control and digital compressor operation can-
not be supported simultaneously.
Hardware Requirements
• space temperature sensor
• return/mixed air sensor
• supply air sensor
This control scheme requires a supply air sensor and a re-
turn air sensor or mixed air sensor. In lieu of wiring sensors to
the 38AP unit, both values can be communicated via CCN to
the 38AP unit. For information on broadcasting values, see
Thermistors on page 28. The Supply Air Thermistor (
Configu-
ration
o
OPT1
o
SAT.T
) and Return Air Thermistor (
Configu-
ration
o
OPT1
o
RAT.T
) must be configured for either
0
(5
k
:
) or
1
(10 k
:
) type sensors, whether they are hard wired or
their values are communicated to the controller.
A space temperature sensor must be installed (T55, T56 or
T59) and enabled (
Configuration
o
OPT1
o
SPT.S
). If a T56
or T59 sensor with space temperature offset is installed with
the space temperature offset slider, it must be enabled
(
Configuration
o
OPT1
o
SP.O.S
) to affect the unit control.
If a T56 or T59 space temperature offset sensor is in-
stalled, it is possible to configure the range of the slider by ad-
justing this range configuration, Space Temperature Offset
Range (
Configuration
o
OPT1
o
SP.O.R
). The range for this
item is 1 to 10° F (0.6 to 5.6° C); the factory default is 5° F
(2.8° C). With the slider in the neutral position, no offset
is applied.
Required Configurations — Table 31 lists the configurations
required for proper operation.
Recommended Settings — With this Control Type,
CSP.2
should be set to the design Supply Air Temperature.
CSP.1
will
depend on the application. The difference between the default
values for
CSP.1
and
CSP.2
is 5° F (2.8° C). In most cases, the
default differential is acceptable, but the application may
require a smaller or larger difference. For example, a face split
coil may require a larger differential.
CSP.1
should be set to a
value that allows the unit to operate without rapid cycling.
CSP.1
should be greater than
CSP.2
to allow the unit to pro-
duce a lower supply air temperature when a call for High Cool
is made, if the unit has the available capacity.
Space Temperature Cool Set Point (
SPS.P)
should be the
desired room temperature.
Wiring — See Fig. 83.
Table 31 — C.TYP=5 (SPT Multi) Required Configuration
*If equipped.
CONFIGURATION MODE
SUBMODE
ITEM
DISPLAY
ITEM DESCRIPTION
COMMENT
OPT1
SPT.S
ENBL/DSBL
Space Temp Sensor
Default: DSBL
Set to ENBL. Cannot be enabled until
C.TYP=5. If C.TYP=5, this item is auto-
matically enabled.
SPT.O.S
ENBL/DSB
Space Temp Offset
Enable
Default: DSBL
Set to ENBL if T56 Thermostat is
installed and temperature offset is to be
used.
SPT.O.R*
XX
ǻ
F (
ǻ
C)
Space Temp Offset
Range
Range: 1 to 10
ǻ
F (0.6 to 5.6
ǻ
C)
Default: 5
ǻ
F (2.8
ǻ
C)
RAT.T
X
RAT Thermistor Type
Default: 0
Range: 0 to 2
Must be set for appropriate value:
0 = 5 k
:
1 = 10 k
:
2 = None
SAT.T
X
SAT Thermistor Type
Default: 0
Range: 0 to 2
Must be set for appropriate value:
0 = 5 k
:
1 = 10 k
:
2 = None
OPT2
C.TYP
X
Machine Control Type
Default: 4
Range: 1 to 9
Set Item to 5 (SPT Multi)
SETPOINTS MODE
COOL
CSP.1
XX.X
Cooling Setpoint 1
Default: 60.0 F (15.6 C)
Range: 40.0 to 80.0 F (4.4 to 26.7 C)
CSP.2
XX.X
Cooling Setpoint 2
Default: 55.0 F (12.8 C)
Range: 40.0 to 80.0 F (4.4 to 26.7 C)
SPS.P
XX.X
Space T Cool Setpoint
Default: 78.0 F (25.6 C)
Range: 65.0 to 80.0 F (18.3 to 26.7 C)
L.C.ON
X
Lo Cool On Setpoint
Default: 1
'
F (0.6
'
C)
–1 to 2
'
F (–0.6 to 1.1
'
C)
H.C.ON
Hi Cool On Setpoint
Default: 3
'
F (1.7
'
C)
0.5 to 20
'
F (0.3 to 11.1
'
C)
L.C.OF
Lo Cool Off Setpoint
Default: 0.5
'
F (0.3
'
C)
0.5 to 2
'
F (0.3 to 1.1
'
C)