Lennox LHT Series Information

TABLE 10
DIRECT DRIVE BLOWER MOTOR TROUBLESHOOTING
Failure Error Warning Reason Troubleshoot
Locked Rotor • No changes in hall signals within 2000ms
Check for obstruction keeping
impeller from rotating
Braking Mode •
Warning, no error code set, Motor start not pos
sible after 20 sec
Check for secondary airflow source in the system causing
the impeller to
rotate backwards when off
Hall Error •
Combination of 3 hall signals gives false signal
after one rotation
Measure voltage across each leg, Check electrical connec
tions
Power Module Overheat
ed
• Temperature > 115C
Check operating conditions in blower compartment, Check
for high motor load (current draw), Check for
corrosion-free and secure electrical connections
Motor Overheated • Motor over-temperature protector opens
Gate Driver Error • Internal software fault
Measure voltage across each leg, Check electrical connec
tions
Phase Failure • Input voltage has phase imbalance
Measure voltage across each leg, Check electrical connec
tions, Repair low/high voltage leg(s)
DC Link Voltage Low • Rectified DC link voltage is too low
DC Link Over-voltage • Rectified DC link voltage is too high
Line Over-voltage • Line voltage too high
Line Under-voltage • Line voltage too low
Communication Error •
Internal communication failure. Not connected
with master/slave wiring
Check low voltage wiring connections
DC Link Voltage Low • Warning, not low enough to set error code
Measure voltage across each leg, Check electrical connec
tions, Repair low/high voltage leg(s)
Electronics Temp High •
Warning, not high enough to set error code,
Temperature > 95C
Check operating conditions in blower compartment, Check
for high motor load (current draw), Check for
corrosion-free and secure
electrical connections
Power Module Temp High •
Warning, not high enough to set error code,
Temperature > 105C
Motor Temp High •
Warning, not high enough to set error code,
Temperature > 130C

Lennox LHT Series Specifications

General

Brand	Lennox
Model	LHT Series
Category	Heat Pump
Language	English