Carrier 38MGR Series Service Manual

Carrier 38MGR Series Service Manual Manual pdf 26 page image

26 Specifications subject to change without notice. 38MGR-04SMELECTRONIC FUNCTIONAbbreviation• T1: Indoor ambient temperature• T2: Middle indoor heat exchanger coil temperature• T2B: Indoor heat exchanger exhaust coil temperature (located onthe outdoor unit)• T3: Outdoor heat exchanger pipe temperature• T4: Outdoor ambient temperature• T5: Compressor discharge temperatureElectric Control Working Environment• Input voltage: 230V• Input power frequency: 60Hz• Indoor fan standard working amp.: <1A• Outdoor fan standard working amp.: <1.5A• Four-way valve standard amp.: <1AMain ProtectionCompressor Restart DelayThe compressor takes one minute to start up the first time. Furtherrestarts take three minutes.Compressor Discharge Temperature ProtectionWhen the compressor’s discharge temperature rises, the runningfrequency is limited according to the following rules:• If 221°F (105°C)  T5<230°F (110°C), maintain the currentfrequency.• If the temperature increases and T5230°F, decrease thefrequency to a lower level every two minutes until F1.• If T5239°F (115°C) for ten seconds, the compressor stops andthen restarts until T5<194°F (90°C).Fan Speed MalfunctionIf the outdoor fan speed is lower than 100RPM or higher than2400RPM for 60 seconds or more, the unit stops and the LED displaysan E8 failure code.Inverter Module ProtectionThe inverter protection module ensures that faults related to current,voltage, or temperature do not damage the inverter.Low Voltage ProtectionFig. 27 — Low Voltage ProtectionIf these protections are triggered, the A/C unit stops and the LEDdisplays the failure code. The unit restarts three minutes after theprotection mechanism turns off.NOTE: If the low voltage protection triggers and thevoltage does not restore to normal within threeminutes, the protection remains active even afterthe unit restarts.Compressor Current Limit ProtectionThe temperature interval for the current limit is the same as the rangeof the T4 frequency limit.Fig. 28 — Cooling ModeTable 23 — Cooling ModeFig. 29 — Heating ModeTable 24 — Heating ModeIndoor / Outdoor Units Communication ProtectionIf the indoor units do not receive the feedback signal from the outdoorunits for two consecutive minutes, the unit stops and displays a failurecode.VOLTAGENo limitVOLT_LTM_FREQ1_ADDVOLT_LTM_FREQ2_ADDCoolReturnI Difference between current limit andshutdown currentCoolT4Zone5I Cooling T4≥50 °C current limit valueCoolT4Zone4I Cooling 49＞T4≥45 °C current limit valueCoolT4Zone3I Cooling 44＞T4≥41°C current limit valueCoolT4Zone2I Cooling 40﹥T4≥33 °C current limit valueCoolT4Zone1I Cooling 32＞T4 °C current limit valueCoolStopI Cooling stop protection current valueHeatReturnI Difference between current limitand shutdown currentHeatT4Zone4I Heating T4≥15°C current limit valueHeatT4Zone3I Heating 14＞T4≥10°C current limit valueHeatT4Zone2I Heating 9＞T4≥6°C current limit valueHeatT4Zone1I Heating 5＞T4 current limit valueHeatStopI Heating stop protection current value5049454441403332151410965HeatT4Zone4IHeatT4Zone3IHeatT4Zone2IHeatT4Zone1I