77
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
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.
SN.1.4
Econ 1 Out Ser Number 4
0-254
ECN1_SN4
0
C.A.L1
Ecn1 Out Ctl Angl Lo Lmt
0-90
ECONCALM
85
SN.2.1
Econ 2 Ret Ser Number 1
0-9999
ECN2_SN1
0
SN.2.2
Econ 2 Ret Ser Number 2
0-6
ECN2_SN2
0
SN.2.3
Econ 2 Ret Ser Number 3
0-9999
ECN2_SN3
0
SN.2.4
Econ 2 Ret Ser Number 4
0-254
ECN2_SN4
0
C.A.L2
Ecn2 Ret Ctl Angl Lo Lmt
0-90
ECN2CALM
85
SN.3.1
Econ 3 Out Ser Number 1
0-9999
ECN3_SN1
0
SN.3.2
Econ 3 Out Ser Number 2
0-6
ECN3_SN2
0
SN.3.3
Econ 3 Out Ser Number 3
0-9999
ECN3_SN3
0
SN.3.4
Econ 3 Out Ser Number 4
0-254
ECN3_SN4
0
C.A.L3
Ecn3 Out Ctl Angl Lo Lmt
0-90
ECN3CALM
85
T.24.C
TITLE 24 CONFIGS
LOG.F
Log Title 24 Faults
No/Yes
T24LOGFL
No
EC.MD
T24 Econ Move Detect
1 to 10
T24ECMDB
1
EC.ST
T24 Econ Move SAT Test
10 to 20
T24ECSTS
10
S.CHG
T24 Econ Move SAT Change
0 to 5
T24SATMD
0.2
E.SOD
T24 Econ RAT-OAT Diff
5 to 20
T24RATDF
15
E.CHD
T24 Heat/Cool End Delay
0 to 60
T24CHDLY
25
ET.MN
T24 Test Minimum Pos.
0 to 50
T24TSTMN
15
ET.MX
T24 Test Maximum Pos.
50 to 100
T24TSTMX
85
SAT.T
SAT Settling Time
10 to 900
SAT_SET
240
AC.EC
Economizer Deadband Temp
0 to 10
AC_EC_DB
4
E.GAP
Econ Fault Detect Gap
2 to 100
EC_FLGAP
5
E.TMR
Econ Fault Detect Timer
10 to 240
EC_FLTMR
20
X.CFM
Excess Air CFM
400 to 4000
EX_ARCFM
800
X.TMR
Excess Air Detect Timer
30 to 240
EX_ARTMR
150
AC.MR
T24 AutoTest SF Run Time
1 to 10
T24ACMRT
2
AC.SP
T24 Auto-Test VFD Speed
10 to 50
T24ACSPD
20
AC.OP
T24 Auto-Test Econ % Opn
1 to 100
T24ACOPN
30
VF.PC
T24 Auto-Test VFD % Chng
1 to 20
T24VFDPC
10
EC.DY
T24 Econ Auto-Test Day
0=Never,
1=Monday,
2=Tuesday,
3=Wednesday,
4=Thursday,
5=Friday,
6=Saturday,
7=Sunday
T24_ECDY
6=Saturday
EC.TM
T24 Econ Auto-Test Time
0 to 23
T24_ECTM
2
Table 54 —
Economizer Configuration Table (cont)
ITEM
EXPANSION
RANGE
UNITS
CCN POINT
DEFAULT
Содержание WeatherExpert 48N2
Страница 135: ...135 Fig 18 48 50N Typical Power Schematic Nominal 075 Ton Unit Shown ...
Страница 136: ...136 Fig 19 48 50N Typical Power Schematic Nominal Ton 90 150 Units Shown ...
Страница 137: ...137 Fig 20 48 50N Main Base Board Input Output Connections ...
Страница 138: ...138 Fig 21 48 50N RXB EXB CEM Input Output Connections a48 9307 ...
Страница 139: ...139 Fig 22 48 50N EXV SCB Input Output Connections a48 9308 ...
Страница 140: ...140 Fig 23 48N Typical Modulating Gas Heat Unit Control Wiring ...
Страница 141: ...141 Fig 24 50N Typical Electric Heat Unit Control Wiring ...
Страница 144: ...144 Fig 27 48N Typical Gas Heat Section Wiring Nominal Ton 120 to 150 Units ...
Страница 145: ...145 Fig 28 48 50N Typical Power Component Control Wiring 460 v ...
Страница 146: ...146 Fig 29 48 50N Component Control Wiring 575 v Nominal Ton 075 to 150 Units ...
Страница 147: ...147 Fig 30 48 50N Component Arrangement Power Box ...
Страница 148: ...148 Fig 31 48 50N Component Arrangement Control Box ...
Страница 168: ...168 Fig 47 Sensor and Ignition Position Fig 48 Combustion Blower Details SENSOR DETAILS IGNITION DETAILS ...
Страница 240: ...240 APPENDIX D VFD INFORMATION CONT Fig G VFD Bypass Wiring Diagram WHEN USED ...