Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 95

ITEM
CCN CCN CONFIGURATION
CCNA CCN Address
CCNB CCN Bus Number
BAUD CCN Baud Rate
BROD CCN BROADCST DEFINITIONS
TM.DT
CCN Time/Date Broadcast
OAT.B CCN OAT Broadcast
ORH.B CCN OARH Broadcast
OAQ.B CCN OAQ Broadcast
G.S.B Global Schedule Broadcst
B.ACK CCN Broadcast Ack'er
SC.OV
CCN SCHEDULES-OVERRIDES
SCH.N Schedule Number
HOL.T Accept Global Holidays?
O.T.L. Override Time Limit
OV.EX Timed Override Hours
SPT.O SPT Override Enabled?
T58.O
T58 Override Enabled?
GL.OV Global Sched. Override?
EDT Low Alert Limit/Occ (SA.L.O)
If the space temperature is below the configurable occupied
evaporator discharge temperature (EDT) Low Alert Limit
(SA.L.O), then Alert 302 will be generated and cooling opera-
tion will be stopped, but heating operation will continue. The
alert will automatically reset.
EDT High Alert Limit/Occ (SA.H.O)
If the space temperature is above the configurable occupied
EDT High Alert Limit (SA.H.O), then Alert 303 will be gener-
ated and heating operation will be stopped, but cooling opera-
tion will continue. The alert will automatically reset.
EDT Low Alert Limit/Unocc (SA.L.U)
If the space temperature is below the configurable unoccupied
EDT Low Alert Limit (SA.L.U), then Alert 302 will be gener-
ated and cooling operation will be stopped, but heating opera-
tion will continue. The alert will automatically reset.
EDT High Alert Limit/Unocc (SA.H.U)
If the space temperature is above the configurable unoccupied
EDT High Alert Limit (SA.H.U), then Alert 303 will be gener-
ated and heating operation will be stopped, but cooling opera-
tion will continue. The alert will automatically reset.
RAT Low Alert Limit/Occ (RA.L.O)
If the return-air temperature is below the configurable occu-
pied RAT Low Alert Limit (RA.L.O), then Alert 304 will be
generated and internal routines will be modified. Unit opera-
tion will continue, but VAV heating operation will be disabled.
The alert will automatically reset.
RAT High Alert Limit/Occ (RA.H.O)
If the return-air temperature is above the configurable occupied
RAT High Alert Limit (RA.H.O), then Alert 305 will be generated
and operation will continue. The alert will automatically reset.
RAT Low Alert Limit/Unocc (RA.L.U)
If the return-air temperature is below the configurable unoccu-
pied RAT Low Alert Limit (RA.L.U), then Alert 304 will be
generated. Unit operation will continue, but VAV heating oper-
ation will be disabled. The alert will automatically reset.
RAT High Alert Limit/Unocc (RA.H.U)
If the return-air temperature is above the configurable unoccu-
pied RAT High Alert Limit (RA.H.U), then Alert 305 will be
generated. Operation will continue. The alert will automatical-
ly reset.
Table 61 — CCN Configuration
EXPANSION
1 to 239
0 to 239
1 to 5
Off/On
Off/On
Off/On
Off/On
Off/On
Off/On
0 to 99
No/Yes
0 to 4
0 to 4
No/Yes
No/Yes
No/Yes
RANGE UNITS
CCNADD
CCNBUS
CCNBAUDD
CCNBC
OATBC
OARHBC
OAQBC
GSBC
CCNBCACK
SCHEDNUM
HOLIDAYT
HRS OTL
HRS OVR_EXT
SPT_OVER
T58_OVER
GLBLOVER
OAT Low Alert Limit (OAT.L)
If the outside-air temperature measured by the OAT thermistor
is below the configurable OAT Low Alert Limit (OAT.L), then
Alert T316 will be generated.
OAT High Alert Limit (OAT.H)
If the outside-air temperature measured by the OAT thermistor
is above the configurable OAT High Alert Limit (OAT.H), then
Alert T317 will be generated.
RARH Low Alert Limit (R.RH.L)
If the unit is configured to use a return air relative humidity
sensor (Configuration  UNIT  SENS  RRH.S), and the
measured level is below the configurable RH Low Alert Limit
(R.RH.L), then Alert 308 will occur. The unit will continue to
run, and the alert will automatically reset.
RARH High Alert Limit (R.RH.H)
If the unit is configured to use a return air relative humidity
sensor (Configuration  UNIT  SENS  RRH.S), and the
measured level is above the configurable RARH High Alert
Limit (R.RH.H), then Alert 309 will occur. The unit will con-
tinue to run, and the alert will automatically reset.
OARH Low Alert Limit (O.RH.L)
If the unit is configured to use an outdoor air relative humidity
sensor (Configuration  ECON  ORH.S) and the measured
level is below the configurable OARH Low Alert Limit
(O.RH.L), then economizer operation will be disabled. The
unit will continue to run, and the alert will automatically reset.
OARH High Alert Limit (O.RH.H)
If the unit is configured to use a return air relative humidity
sensor (Configuration  ECON  ORH.S) and the measured
level is above the configurable OARH High Alert Limit
(O.RH.H), then economizer operation will be disabled. The
unit will continue to run, and the alert will automatically reset.
Supply Duct Pressure Low Alert Limit (SP.L)
If the unit is a VAV unit with a supply duct pressure sensor and the
measured supply duct static pressure is below the configurable SP
Low Alert Limit (DP.L), then Alert 310 will occur. The unit will
continue to run, and the alert will automatically reset.
Supply Duct Pressure High Alert Limit (SP.H)
If the unit is a VAV unit with a supply duct pressure sensor and the
measured supply duct static pressure is above the configurable SP
High Alert Limit (SP.H), then Alert 311 will occur. The unit will
continue to run, and the alert will automatically reset.
95
CCN POINT DEFAULT
1
0
3
On
Off
Off
Off
Off
Off
1
No
1
0
Yes
Yes
No