Controls, Start-Up, Operation, Service and ... - Climayoreo

T072 (Evaporator Discharge Reset Sensor Failure) — This
sensor is responsible for third party reset of the cooling supply
air set point. If the unit is configured for “third party reset”
(ConfigurationEDT.RRS.CF=3) and this alert occurs, no
reset will be applied to the cooling supply air set point. Recovery
from this alert is automatic. Reason for error is either a
faulty sensor, wiring error, or damaged input on the CEM
board.
T073 (Outside Air Temperature Thermistor Failure) — Failure
of this thermistor (TemperaturesAIR.TOAT) will disable
any elements of the control which requires its use. Economizer
control beyond the vent position and the calculation of
mixed air temperature for the SumZ algorithm will not be possible.
Recovery from this alert is automatic. Reason for error is
either a faulty thermistor, wiring error, or damaged input on the
MBB control board.
T074 (Space Temperature Thermistor Failure) — Failure of
this thermistor (TemperaturesAIR.TSPT) will disable
any elements of the control which requires its use. If the unit is
configured for SPT 2 stage or SPT multi-stage operation and
the sensor fails, no cooling or heating mode may be chosen.
Recovery from this alert is automatic. Reason for error is either
a faulty thermistor in the T55, T56 or T58 device, wiring error,
or damaged input on the MBB control board.
T075 (Return Air Thermistor Failure) — Failure of this
thermistor (TemperaturesAIR.TRAT) will disable any elements
of the control which requires its use. Elements of failure
include:
• the calculation of mixed air temperature for sumZ control
• the selection of a mode for VAV units
• economizer differential enthalpy or dry bulb control
• RAT offset control for dehumidification
• return air temperature supply air reset
• fan tracking for building pressure control.
Recovery from this alert is automatic. Reason for error is
either a faulty thermistor, wiring error, or damaged input on the
MBB control board.
T076 (Outside Air Relative Humidity Sensor Failure) —
Failure of this sensor (InputsREL.HOA.RH) will disable
any elements of the control which requires its use. Elements of
failure include: economizer outdoor and differential enthalpy
control. Recovery from this alert shall be automatic. Reason for
error is either a faulty sensor, wiring error or damaged input on
the CEM control board.
T077 (Space Relative Humidity Sensor Failure) — Failure
of this sensor (InputsREL.HSP.RH) will disable any elements
of the control which requires its use. Elements of failure
include humidification and dehumidification. Recovery from
this alert is automatic. Reason for error is either a faulty sensor,
wiring error, or damaged input on the CEM control board.
T078 (Return Air Relative Humidity Sensor Fail) — Failure
of this sensor (InputsREL.HRA.RH) will disable any elements
of the control which requires its use. Elements of failure
include economizer differential enthalpy control, humidification,
and dehumidification. Recovery from this alert is automatic.
Reason for error is either a faulty sensor, wiring error, or
damaged input on the CEM control board.
T082 (Space Temperature Offset Sensor Failure) — When
this failure occurs, there is no offset available that may be applied
to space temperature. Recovery from this alert is automatic.
Reason for error is either a faulty slider potentiometer, wiring
error, or damaged input on the MBB control board.
T090 (Circ A Discharge Press Transducer Failure)
T091 (Circ B Discharge Press Transducer Failure) — The
associated circuit becomes disabled whenever this transducer
(PressuresREF.PDP.A, DP.B) fails. Recovery from this
alert is automatic. Reason for error is either a faulty sensor, wiring
error, or damaged input on the MBB control board.
111
T092 (Circ A Suction Press Transducer Failure)
T093 (Circ B Suction Press Transducer Failure) — The associated
circuit becomes disabled whenever this transducer
(PressuresREF.PSP.A, SP.B) fails. Recovery from this
alert is automatic. Reason for error is either a faulty sensor, wiring
error, or damaged input on the MBB control board.
T110 (Circuit A Loss of Charge)
T111 (Circuit B Loss of Charge) — Alert codes 110 and 111
are for circuits A and B respectively. These alerts occur when
all the compressors on a circuit are OFF and the suction pressure
is less than 18 psig, if the OAT is above –5 F for 1 continuous
minute. The alert will automatically clear when the suction
pressure transducer reading is valid and greater than
54 psig. The cause of the alert is usually low refrigerant pressure
or a faulty suction pressure transducer.
P120 (Circuit A Low Saturated Suction Temp. Comp Shutdown)
T120 (Circuit A Low Saturated Suction Temperature Alert)
A120 (Circuit A Low Saturated Suction Temperature
Alarm)
P121 (Circuit B Low Saturated Suction Temp. Comp Shutdown)
T121 (Circuit B Low Saturated Suction Temperature Alert)
A121 (Circuit B Low Saturated Suction Temperature
Alarm) — This alert/alarm is used to keep the evaporator coils
from freezing and the saturated suction temperature above the
low limit for the compressors.
When TemperaturesREF.TSSTA or Temperatures
REF.TSSTB is less than 20 F for 4 minutes, less than 10 F
for 2 minutes, less than 0° F for 1 minute, or less than –20 F for
20 seconds continuously, a compressor of the affected circuit
will be shut down with a local pre-alert (P120, P121) and a
15-minute timeguard will be added to the compressor. If the
saturated suction temperature continues to be less than 20 F for
4 minutes, less than 10 F for 2 minutes, less than 0° F for 1
minute, or less than –20 F for 20 seconds continuously, another
compressor of the affected circuit, if it exists, will be shut down
with a local pre-alert (P120, P121) and a 15-minute timeguard
will be added to the compressor. This sequence will continue
until the last compressor on the circuit is shutdown, at which
time the circuit will be shut down with alert (T120, T121).
This failure follows a 3-strike methodology. When the circuit
is shutdown entirely, an alert (T120, T121) is generated
and a strike is logged on the circuit. The Alert and strikes
logged will automatically reset if the saturated suction temperature
remains above 29.4 F for 15 minutes. On the third strike,
alarm (A120, A121) will be generated which will necessitate a
manual reset to get the circuit back running. It is important to
note that a strike is called out only if all compressors in the circuit
are off at the time of alert.
To prevent nuisance alerts, P120 and P121 show up in the
alarm history and locally at the display, but are never broadcast
to the network. To recover from these pre-alerts, both a 15 minute
hold off timer and saturated suction temperature rising
above 29.4 F must occur. If recovery occurs, staging will be allowed
on the circuit once again. A strike is tied to the circuit
going off entirely, not reducing capacity and recovering. Therefore
it is possible that multiple P120 and P121 alerts may be
stored in alarm history but not broadcast.
T122 (Circuit A High Saturated Suction Temperature)
T123 (Circuit B High Saturated Suction Temperature) —
This alert is for display purposes only. No action is taken by the
control when the alert occurs.
When TemperaturesREF.TSSTA or Temperatures
REF.TSSTB is greater than 70 F for Configuration
COOLH.SST minutes, local alert T122 or T123 will occur.
The alerts automatically reset when the corresponding saturated
suction temperature drops below 70 F.