Danfoss TTS400

Compressor Status
Description
Trigger Method Troubleshooting
faults.
Recommendation:
l
Ensuretheliquidmotor-coolinglinehassufficientliquidsupplyandisnotblocked.
l
Preventprolongedoperationatapressureratiolessthan1.5.

o
LowLiftoperationrequiresadditionalconsiderations,refertoApplications
Manual
l
Verifythesolenoidsareoperationalandnotblocked.RefertoSection4.6.3Solenoid
Verificationonpage73.
l
Verifythesolenoidactuators.RefertoSection4.6.3SolenoidVerificationonpage73.
l
VerifytheSerialDriver.RefertoSection4.26.3SerialDriverVerificationonpage217.
l
Verifycavitytemperaturesensor.RefertoSection4.31.3CavityTemperatureSensor
Verificationonpage242.
LowLeavingFluid
TemperatureFault
DFT
l
(RemovedfromCC4.X.Xsoftware)
l
Suggestsinsufficientevaporatorfluidfloworinsufficientsystemload.
l
Checkevaporatorfluidflowandsystemload.
l
Verifyleavingfluidtemperaturesensor.
l
EnsureLEAVEjumperisinstalledontheI/Oboard.
l
Reviewthefaultlogforenteringandleavingair/watertemperature(ifavailable)and
otherconditionsthatarerecordedatthetimeoffault.
HighPressureRatio
Fault
AFT
l
Suggeststhecondenserressureishigh,notenoughloadontheevaporator,or
insufficientwater/airflowineithercondenserorevaporator.
l
Checktheelectronicexpansionvalve(EXV)operation,condenser,evaporatorloads,and
water/airflow.
l
Reviewthefaultlogforsuctionanddischargepressuresandotherconditionsthatare
recordedatthetimeoffault.
Bearing/MotorFault
Active
INS
l
IfaMotorFaulttypeoraBearingFaulttypeispresent,theBearing/MotorFaultis
triggered.
l
Thisisnotanactualfault,onlyanindicationthatafaulthasoccurredintheMotoror
Bearingsection.RefertoTable5-8Motor/SystemStatusonpage260andTable5-5
BearingFaultTypesonpage254.
SensorFault RFT
l
Reviewfaultlogforindicationofvaluesoutofspecifiedrangesrecordedattimeoffault.
Verifythequestionablesensorandrelatedconnectionsforfailure.
l
Invertertemperature:ThesensorembeddedintheInverterrequiresareplacementof
theInverterifdeterminedfaulty.
l
CavityTemperature:RefertoSection4.31.3CavityTemperatureSensorVerificationon
page242.
l
SuctionTemperature:Verifysuctionpressure/temperaturesensor.RefertoSection4.32.3
Pressure/TemperatureSensorVerificationonpage246.
l
DischargeTemperature:Verifydischargepressure/temperaturesensor.RefertoSection
4.32.3Pressure/TemperatureSensorVerificationonpage246.
l
LeavingWaterTemperature:VerifyLEAVEjumperisinstalledonI/Oboard.
l
SuctionPressure:Reviewfaultlogforrecordedvalue.
l
DischargePressure:Reviewfaultlogforrecordedvalue.
HighSCR
TemperatureFault
AFT RemovedfromCC4.2.Xandlatersoftware
l
IndicatestheSCRcoolingisinsufficient.
l
Ifthisfaultoccursthreetimeswithina30-minuteperiod,aLock-OutFaultwilloccur.
M-SV-001-EN Rev. H-1/23/2023 Page 257 of 294