Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 77

ITEM
SN.1.4
Econ 1 Out Ser Number 4
C.A.L1
Ecn1 Out Ctl Angl Lo Lmt
SN.2.1 Econ 2 Ret Ser Number 1
SN.2.2 Econ 2 Ret Ser Number 2
SN.2.3 Econ 2 Ret Ser Number 3
SN.2.4 Econ 2 Ret Ser Number 4
C.A.L2
Ecn2 Ret Ctl Angl Lo Lmt
SN.3.1
Econ 3 Out Ser Number 1
SN.3.2 Econ 3 Out Ser Number 2
SN.3.3 Econ 3 Out Ser Number 3
SN.3.4 Econ 3 Out Ser Number 4
C.A.L3 Ecn3 Out Ctl Angl Lo Lmt
T.24.C
TITLE 24 CONFIGS
LOG.F
Log Title 24 Faults
EC.MD T24 Econ Move Detect
EC.ST T24 Econ Move SAT Test
S.CHG T24 Econ Move SAT Change
E.SOD T24 Econ RAT-OAT Diff
E.CHD
T24 Heat/Cool End Delay
ET.MN
T24 Test Minimum Pos.
ET.MX T24 Test Maximum Pos.
SAT.T SAT Settling Time
AC.EC Economizer Deadband Temp
E.GAP Econ Fault Detect Gap
E.TMR Econ Fault Detect Timer
X.CFM
Excess Air CFM
X.TMR Excess Air Detect Timer
AC.MR T24 AutoTest SF Run Time
AC.SP T24 Auto-Test VFD Speed
AC.OP T24 Auto-Test Econ % Opn
VF.PC T24 Auto-Test VFD % Chng
EC.DY T24 Econ Auto-Test Day
EC.TM T24 Econ Auto-Test Time
ECONOMIZER OPERATION
Is Economizer Enabled?
If an economizer is not being used or is to be completely dis-
abled, the configuration option EC.EN may be set to NO. Oth-
erwise the economizer enabled configuration must be set to
YES. Without the economizer enabled, the outdoor-air damp-
ers will open to minimum position when the supply fan is run-
ning. Outdoor-air dampers will spring-return closed upon loss
of power or shutdown of the supply fan.
What is the Economizer Minimum Position?
The configuration option EC.MN is the economizer minimum po-
sition. See the section on Indoor Air Quality for further informa-
tion on how to reset the economizer even further to gain energy
savings and to more carefully monitor "indoor IAQ problems."
What is the Economizer Maximum Position?
The upper limit of the economizer may be clamped if so de-
sired via configuration option EC.MX. It defaults to 98% to
avoid problems associated with slight changes in the econo-
mizer damper's end stop over time. Typically this will not need
to be adjusted.
What is Economizer Trim for Sum Z?
A strange title, but a simple explanation. Sum Z stands for the
adaptive cooling control algorithm used for multiple stages of
compression. The configuration option E.TRM is typically set to
Table 54 — Economizer Configuration Table (cont)
EXPANSION RANGE UNITS
0-254
0-90
0-9999
0-6
0-9999
0-254
0-90
0-9999
0-6
0-9999
0-254
0-90
No/Yes
1 to 10
10 to 20
0 to 5
5 to 20
0 to 60
0 to 50
50 to 100
10 to 900
0 to 10
2 to 100
10 to 240
400 to 4000
30 to 240
1 to 10
10 to 50
1 to 100
1 to 20
0=Never,
1=Monday,
2=Tuesday,
3=Wednesday,
4=Thursday,
5=Friday,
6=Saturday,
7=Sunday
0 to 23
Yes, and allows the economizer to modulate to the same control
point "Sum Z" uses to control compressor staging. The advan-
tage is lower compressor cycling coupled with tighter tempera-
ture control. Setting this option to "No" will cause the economiz-
er, if it is indeed able to provide free cooling, to open to the
Economizer Max. Position (EC.MX) during mechanical cooling.
ECONOMIZER CHANGEOVER SELECTION
There are 4 potential elements at play that may run concurrent-
ly, which determine whether the economizer is able to provide
free cooling:
• Dry Bulb Changeover (outside air temperature qualifica-
tion)
• The Enthalpy Switch (discrete switch input monitoring)
• Economizer Changeover Select (E.SEL economizer
changeover select configuration option)
• Outdoor Dewpoint Limit Check (needs an outdoor relative
humidity sensor installed)
Dry Bulb Changeover
Outside-air temperature may be viewed under Tempera-
tures  AIR.T  OAT.
The control constantly compares its outside-air temperature
reading against OAT.L. If the temperature reads above OAT.L,
the economizer will not be allowed to perform free cooling.
77
CCN POINT DEFAULT
ECN1_SN4 0
ECONCALM 85
ECN2_SN1 0
ECN2_SN2 0
ECN2_SN3 0
ECN2_SN4 0
ECN2CALM 85
ECN3_SN1 0
ECN3_SN2 0
ECN3_SN3 0
ECN3_SN4 0
ECN3CALM 85
T24LOGFL No
T24ECMDB 1
T24ECSTS 10
T24SATMD 0.2
T24RATDF 15
T24CHDLY 25
T24TSTMN 15
T24TSTMX 85
SAT_SET 240
AC_EC_DB 4
EC_FLGAP 5
EC_FLTMR 20
EX_ARCFM 800
EX_ARTMR 150
T24ACMRT 2
T24ACSPD 20
T24ACOPN 30
T24VFDPC 10
T24_ECDY 6=Saturday
T24_ECTM 2