Lennox MPB036S4M

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31. SpecicationsandOperations
Table 20. Electronic Functions Abbreviations
T1 Indoor ambient temperature
T2 Coiltemperatureofindoorheatexchanger
T2B Coiltemperatureofindoorheatexchangeroutlet.(locatedinoutdoorunit)
T3 Pipetemperatureofoutdoorheatexchanger
T4 Outdoorambienttemperature
T5 Compressordischargetemperature
Table 21. Electronic Control Working Environment
Inputvoltage:230V
Inputpowerfrequency:60Hz
Indoorfannormalworkingamp.islessthan1A
Outdoorfannormalworkingampislessthan1.5A
Four-wayvalvenormalworkingampislessthan1A
Table 22. Main Protection
Threeminutesdelayatrestartforcompressor
Oneminutedelayforthersttimestart-upandthreeminutesdelayforothers
Temperatureprotectionofcompressordischarge
Whenthecompressordischargeisgettinghigher,therunningfrequencywillbelimitedasbelowrules:
If215.6°F(102°C)<T5<244.4°F(115°C),decreasethefrequencytothelowerleveleverytwominutesuntiltoF1.
IfT5<244.4°F(115°C)fortenseconds,thecompressorwillstopandrestarttillT5<194°F(90°C)
Table 23. Indoor/Outdoor Units Communication Protection
Iftheindoorunitscannotreceivethefeedbacksignalfromtheoutdoorunitsfortwominutes,theunitwillstopanddisplayfailure.
HighCondenserColTemp
Protection
WhenT3>149°F(65°C)forthreeseconds,thecompressorwillstopwhiletheindoorfanandoutdoorfanwillcontinue.
WhenT3<125.6°F(52°C),theprotectionwillreleaseandthecompressorwillrestartafterthreeminutes.
OutdoorUnitAnti-Freezing
Protection
WhenT2B<32°F(0°C)for250seconds,theindoorunitcapacitydemandwillbezeroandresumetonormalwhen
T2B>50°F(10°C).
RunningRules
1.IfthecompressorfrequencykeepslowerthanRET_OIL_FREQ1_ADDforRET_OIL_TIME1_ADD,theACwillrise
thefrequencytoRET_OIL_FREQ2_ADDforRET_OIL_TIME2_
2.Duringtheoilreturnprocess,theEXVwillkeep300pwhiletheindoorunitswillkeepthecurrentrunningmode.
Table 24. Compressor Preheating Functions
Preheatingpermitting
condition
IfT4(outdoorambienttemperature)<37.4°F(3°C)andnewlypoweredonorifT4<37.4°F(3°C)andcompressorhas
stoppedforover3hours,thecompressorheatingcablewillwork.
PreheatingMode
Aweakcurrentowthroughthecoilofcompressorfromthewiringterminalofcompressor,thenthecompressoris
heatedwithoutoperation.
PreheatingRelease
Condition
IfT4>41°F(5°C)orthecapacitydemandisn’tzero,preheatingfunctionwillstop.
Table 25. Compressor Crankcase Heater
Preheatingpermitting
condition
WhenT4<37.4°F(3°C)within5secondsofbeingpluggedin,thecrankcaseheaterwillbeactive.
WhenT4<37.4°F(3°C)andthecompressorisnotrunningfor3hours,thecrankcaseheaterwillbeactive.
PreheatingRelease
Condition
IfT4>41°F(5°C)ortheindoorhascapacitydemand,thecrankcaseheaterwillstopwork.