100
override. Recovery is automatic. Reason for error is either a
faulty sensor, wiring error, or damaged input on the MBB con-
trol board. This error only occurs when the unit is configured
for minimum position override and a 4-20 mA signal is not
present.
T245 (Outside Air Cfm Sensor Failure) — If the outside air cfm
sensor (Inputs
→
CFM
→
O.CFM) fails, the economizer will de-
fault to discrete positioning of the economizer (Configuration
→
IAQ
→
DCV.C
→
IAQ.M, Configuration
→
Econ
→
EC.MN).
Recovery is automatic. Reason for error is either a faulty sensor,
wiring error, or damaged input on the CEM control board.
T246 (Supply Air Cfm Sensor Failure) — If the supply air
cfm sensor (Inputs
→
CFM
→
S.CFM) fails, fan tracking is not
possible and the system will shut down. Recovery is automatic.
Reason for error is either a faulty sensor, wiring error, or dam-
aged input on the ECB control board.
T247 (Return Air Cfm Sensor Failure) — If the return air
cfm sensor (Inputs
→
CFM
→
R.CFM) fails, fan tracking is not
possible and the system will shut down. Recovery is automatic.
Reason for error is either a faulty sensor, wiring error, or dam-
aged input on the ECB control board.
T300 (Space Temperature Below Limit) — If the space tem-
perature is below the configurable SPT Low Alert Limits (occu-
pied [Configuration
→
ALLM
→
SP.L.O] for 5 minutes or
unoccupied [Configuration
→
ALLM
→
SP.L.U] for 10 min-
utes), then an alert will be broadcast. The alert will automatically
reset.
T301 (Space Temperature Above Limit) — If the space tem-
perature is above the configurable SPT High Alert Limits
(occupied [Configuration
→
ALLM
→
SP.H.O] for 5 minutes or
unoccupied [Configuration
→
ALLM
→
SP.H.U] for 10 min-
utes), then an alert will be broadcast. The alert will automati-
cally reset.
T302 (Supply Temperature Below Limit) — If the supply-air
temperature measured by the supply temperature sensor is below
the configurable SAT LO Alert Limit/Occ (Configuration
→
ALLM
→
SA.L.O) for 5 minutes or the Low Supply air tempera-
ture alert limit unoccupied mode (Configuration
→
ALLM
→
SA.L.U) for 10 minutes, then an alert will be broadcast.
T303 (Supply Temperature Above Limit) — If the supply
temperature is above the configurable SAT HI Alert Limit Occ
(Configuration
→
ALLM
→
SAH.O) for 5 minutes or the SAT
HI Alert Limit/Unocc (Configuration
→
ALLM
→
SA.H.U) for
10 minutes, then an alert will be broadcast. The alert will auto-
matically reset.
T304 (Return Air Temperature Below Limit) — If the re-
turn air temperature measured by the RAT sensor is below the
configurable RAT LO Alert Limit/Occ (Configuration
→
ALLM
→
RA.L.O) for 5 minutes or RAT HI Alert Limit/Occ
(Configuration
→
ALLM
→
RA.L.U) for 10 minutes, then an
alert will be broadcast.
T305 (Return Air Temperature Above Limit) — If the return
air temperature is below the RAT HI Alert Limit/Occ (Configu-
ration
→
ALLM
→
RA.H.O) for 5 minutes or RAT HI Alert
Limit/Occ (Configuration
→
ALLM
→
RA.H.U) for 10 minutes,
then an alert will be broadcast. The alert will automatically reset.
T308 (Return Air Relative Humidity Below Limit) — If the
unit is configured to use a return air relative humidity sensor
through the Return Air RH Sensor (Configuration
→
UNIT
→
SENS
→
RRH.S) setting, and the measured level is below the
configurable RH Low Alert Limit (Configuration
→
ALLM
→
R.RH.L) for 5 minutes, then the alert will occur. The unit will
continue to run and the alert will automatically reset.
T309 (Return Air Relative Humidity Above Limit) — If the
unit is configured to use a return air relative humidity sensor
through the Return Air RH Sensor (Configuration
→
UNIT
→
SENS
→
RRH.S) setting, and the measured level is above the
configurable RH High Alert Limit (Configuration
→
ALLM
→
R.RH.H) for 5 minutes, then the alert will occur. Unit will con-
tinue to run and the alert will automatically reset.
T310 (Supply Duct Pressure Below Limit) — If the unit is a
VAV unit with a supply duct pressure sensor and the measured
supply duct static pressure (Pressures
→
AIR.P
→
SP) is below
the configurable SP Low Alert Limit (Configuration
→
ALLM
→
SP.L) for 5 minutes, then the alert will occur. The unit will
continue to run and the alert will automatically reset.
T311 (Supply Duct Pressure Above Limit) — If the unit is a
VAV unit with a supply duct pressure sensor and the measured
supply duct static pressure (Pressures
→
AIR.P
→
SP) is above
the configurable SP Low Alert Limit (Configuration
→
ALLM
→
SP.H) for 5 minutes, then the alert will occur. The unit will
continue to run and the alert will automatically reset.
T312 (Building Static Pressure Below Limit) — If the unit
is configured to use modulating power exhaust then a
building static pressure limit can be configured using the BP
Low Alert Limit (Configuration
→
ALLM
→
BP.L). If the mea-
sured pressure (Pressures
→
AIR.P
→
BP) is below the limit for
5 minutes then the alert will occur.
T313 (Building Static Pressure Above Limit) — If the unit
is configured to use modulating power exhaust then a
building static pressure limit can be configured using the BP HI
Alert Limit (Configuration
→
ALLM
→
BP.H). If the measured
pressure (Pressures
→
AIR.P
→
BP) is above the limit for
5 minutes, then the alert will occur.
T314 (IAQ Above Limit) — If the unit is configured to use a
CO2 sensor and the level (Inputs
→
AIR.Q
→
IAQ) is above the
configurable IAQ High Alert Limit (Configuration
→
ALLM
→
IAQ.H) for 5 minutes then the alert will occur. The unit will
continue to run and the alert will automatically reset.
FULL
2/3
1/2
1/3
UNTIL CHARGE
450
400
350
300
250
200
150
20 40 60 80 100
SUCTION PRESSURE (PSIG)
DISCHARGE PRESSURE (PSIG)
Fig. 14 — Differential Pressure Chart