Specifications

80
Table 92 — Alert and Alarm Codes (cont)
LEGEND
DIAGNOSTIC ALARM CODES AND POSSIBLE
CAUSES
Alert Codes 51, 52, 55 and 56 (Compressor Safety)
—Alert
codes 51, 52, 55, and 56 are for compressors A1, A2, B1, and
B2 respectively. These alerts occur when the Current Sensor
(CS) does not detect compressor current during compressor
operation. When this occurs, the control turns off the compres-
sor and logs a strike for the respective circuit. These alerts reset
automatically.
If the current sensor board reads OFF while the compressor
relay has been commanded ON for a period of 4 continuous
seconds, an alert is generated.
Any time this alert occurs, a strike will be called out on the
affected compressor. If three successive strikes occur the
compressor will be locked out requiring a manual reset or
power reset of the circuit board. The clearing of strikes during
compressor operation is a combination of 3 complete cycles or
15 continuous minutes of run time operation. So, if there are
one or two strikes on the compressor and three short cycles
(ON-OFF, ON-OFF, ON-OFF) less than 15 minutes each
occur, the strikes will be reset to zero for the affected compres-
sor. Also, if the compressor turns on and runs for 15 minutes
straight with no compressor failure, the compressor's strikes are
cleared as well.
NOTE: Until the compressor is locked out, for the first two
strikes, the alert will not be broadcast to the network, nor will
the alarm relay be closed.
The possible causes are:
• High-pressure switch (HPS) open. The HPS-pressure
switch is wired in series with compressor relays on the
MBB. If the high-pressure switch opens during compressor
operation, the compressor stops, and the CS no longer
detects current, causing the control to activate this alert.
• Compressor internal overload protection is open. The inter-
nal overloads are used on the Scroll Tech compressors
(black) and smaller Maneurop compressors used on the 020,
025, 027, 030, 035 units and 040 A1, A2 compressors.
ALARM
OR
ALERT
NUMBER
DESCRIPTION ACTION TAKEN BY CONTROL
RESET
METHOD
PROBABLE CAUSE
T300 Space Temperature Below Limit
Stop cooling, but continue
to heat
Automatic Outdoor dampers stuck, no load
T301 Space Temperature Above Limit
Stop heating, but continue
to cool
Automatic High load, dampers open
T302 Supply Temperature Below Limit Continue to run unit Automatic
Dampers open, check configuration
setpoint
T303 Supply Temperature Above Limit Continue to run unit Automatic
Dampers open, check configuration
setpoint
T304 Return Temperature Below Limit Continue to run unit Automatic
Dampers open, check configuration
setpoint
T305 Return Temperature Above Limit Continue to run unit Automatic
Dampers open, check configuration
setpoint
T308 Return Air Relative Humidity Below Limit Alert Automatic Configuration error, or sensor error
T309 Return Air Relative Humidity Above Limit Continue to run unit Automatic
Dampers open, check configuration
setpoint
T310 Supply Duct Static Pressure Below Limit Continue to run unit Automatic VFD problem, broken fan belt
T311 Supply Duct Static Pressure Above Limit Continue to run unit Automatic VFD problem, broken fan belt
T312 Building Static Pressure Below Limit Continue to run unit Automatic Exhaust issues, check setpoint
T313 Building Static Pressure Above Limit Continue to run unit Automatic Exhaust issues, check setpoint
T314 IAQ Above Limit Continue to run unit Automatic Damper or IAQ control issues
A404 Fire Shut Down Emergency Mode (fire-smoke) Unit Shutdown Automatic
Smoke detector switch or external
switch
A405 Evacuation Emergency Mode Run power exhaust Automatic Special fire mode control
A406 Pressurization Emergency Mode Run supply fan Automatic Special fire mode control
A407 Smoke Purge Emergency Mode Run supply and exhaust fans Automatic Special fire mode control
T408 Dirty Air Filter Continue to run unit Automatic Dirty filter, switch setting
A409 Supply Fan Status Failure Stop unit Automatic Fan drive failure
T409 Supply Fan Status Failure Continue to run unit Automatic Fan drive failure, or sensor failure
T414 Loss of Communication with the Belimo Actuator Close economizer Automatic
Calibrate economizer, economizer
failure, wiring
T414 Belimo Actuator Direction Error Close economizer Automatic Motor direction switch wrong, wiring
T414 Belimo Actuator Failure Attempt to close economizer Automatic Motor failure
T414 Belimo Actuator Hunting Alert Close economizer Automatic Motor moving too often
T414 Belimo Actuator Range Error Close economizer Automatic Calibrate economizer
T420
R-W1 Jumper Must Be Installed to Run Heat in Service
Te s t
No heat Automatic Add red wire jumpers
T421 Thermostat Y2 Input Activated without Y1 Activated Assume Y2 is Y1 Automatic Thermostat wiring error
T422 Thermostat W2 Input Activated without W1 Activated Assume W2 is W1 Automatic Thermostat wiring error
T423 Thermostat Y and W Inputs Activated Simultaneously Alert Automatic Thermostat issues
T424 Thermostat G Input Not Seen on a Call for Cooling Turn fan on Automatic Thermostat or wiring issues
T500 Current Sensor Board Failure - A1 Stop compressor A1 Automatic Faulty board or wiring
T501 Current Sensor Board Failure - A2 Stop compressor A2 Automatic Faulty board or wiring
T502 Current Sensor Board Failure - B1 Stop compressor B1 Automatic Faulty board or wiring
T503 Current Sensor Board Failure - B2 Stop compressor B2 Automatic Faulty board or wiring
A700 Supply Air Temperature Sensor Failure Stop staged gas heat Automatic Faulty sensor or wiring error
T701 Supply Air Temperature Thermistor 1 Failure Stop staged gas heat Automatic Faulty sensor or wiring error
T702 Supply Air Temperature Thermistor 2 Failure Stop staged gas heat Automatic Faulty sensor or wiring error
T703 Supply Air Temperature Thermistor 3 Failure Stop staged gas heat Automatic Faulty sensor or wiring error
A704 Staged Gas Leaving Air Temp Sum Total Failure Stop staged gas heat Automatic Faulty sensor or wiring error
T705 Limit Switch Thermistor Failure Stop staged gas heat Automatic Faulty switch or wiring
A—Alarm
P—Pre-Alert
T—Alert