131
Outside Air Temperature Reset — The 38AP units are
shipped with an outside air sensor, so no additional sensors are
required.
To use Outside Air Temperature Reset, four variables must
be configured. In
Configuration
o
RSET
, set these items:
• Cooling Reset Type (
CRST
): Configure for the type of
reset desired, Outside Air Temperature
• Remote – No Reset Temp (
RM.NO
): Set to the tempera-
ture that no reset should occur
• Remote – Full Reset Temp (
RM.F
): Set to the tempera-
ture that maximum reset is to occur
• Remote – Degrees Reset (
RM.DG
): Set to the maximum
amount of reset desired
The Outside Air Temperature Reset example shown in Table
60 and Fig. 151 and 152 provides 0° F (0° C) reset to the
Active Set Point (
Run Status
o
VIEW
o
SETP
) if Outside Air
Temperature (
Temperatures
o
UNIT
o
OAT
)=85 F (29.4 C)
and 6 F (3.3 C) reset if
OAT
=55 F (12.8 C). Using these val-
ues, if
SETP
=55 F (12.8 C) and
OAT
=55 F (12.8 C) or less,
the Control Point (
Run Status
o
VIEW
o
CTPT
) will reflect
6° F (3.3° C) reset or 61 F (16.1 C). If
OAT
=85 F (29.4 C) or
more, the control point
Run Status
o
VIEW
o
CTPT
will
reflect 0° F (0.0° C) reset or 55 F (12.8 C). Between
OAT
=55 F (12.8 C) and
OAT
=85 F (29.4 C) a proportional
reset amount will be applied to
CTPT
.
Table 60 — Configuring Outside Air Temperature Reset
*Not supported.
CONFIGURATION
o
OPT2
ITEM
EXPANSION
COMMENTS
EXAMPLE VALUE
C.TYP
Machine Control Type
Range: 1 to 9
1 (VAV)
3 (Tstat Multi)
4 (Tstat 2stg)
5 (SPT Multi)
7 (PCT Cap)
8 (Dual Tstat)
9 (VAV Setpoint)
Default: 4
Value must be set to 1, 3, 5 or 9
1, 3, 5 or 9
CONFIGURATION
o
RSET
CRST
Cooling Reset Type
0=No Reset (Default)
1=4-20 Input
2=Out Air Temp
3=Return*
4=Space Temp
2
RM.NO
Remote – No Reset Temp
Range: 0.0 to 125.0 F
(–17.8 to 51.7 C)
Default: 125.0 F (51.7 C)
85.0 F (29.4 C)
RM.F
Remote – Full Reset Temp
Range: 0.0 to 125.0 F
(–17.8 to 51.7 C)
Default: 0.0 F (–17.8 C)
55.0 F (12.8 C)
RM.DG
Remote – Degrees Reset
Range: –30.0 to 30.0
'
F
(–16.7 to 16.7
'
C)
Default: 0.0
'
F (0.0
'
C)
6.0
'
F
(3.3
'
C)
