Midea ESG-Inv M Series - Page 25

ESG‐InvM
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24  
MideaESG‐InvMSeriesPoolHeatPumpTechnicalManual
Whentheoutdoorunitstops:TheEXVfirstmovesto480(steps)andremainsfor30seconds,thenclosesfully,thenmoves
tothestandbyposition(480(steps)).
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• Four‐wayValveControl 
Thefour‐wayvalveisusedtochangethedirectionofrefrigerantflowthroughthewatersideheatexchangerinorderto
switchbetweencoolingandheatingmode.
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Duringheatingoperation,thefour‐wayvalveison;duringcoolinganddefrostingoperations,thefour‐wayvalveisoff.
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• Fan
Thespeedoftheoutdoorunitfanisadjustedinsteps,asshownbelow
Fanspeedindex
Fanspeed(rpm)
MSC‐70D2N8‐A MSC‐90D2N8‐A MSC‐120D2N8‐A
W1 150 150 150
W2 200 200 200
W3

250 250 250
W4

300 300 300
W5

350 350 350
W6 400 400 400
W7

450 450 450
W8

530 530 530
W9

600 600 600
W10 650 650 650
W11 / 730 730
W12 / 780 780
W13 / / 850
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5 SpecialControl
5.1 OilReturnOperation
Inordertopreventthecompressorfromrunningoutofoil,theoilreturnoperationisconductedtorecoveroilthathas
flowedoutofthecompressorandintotherefrigerantpiping.Whentheoilreturnoperationisbeingconducted,themain
PCBdisplayscoded0.

Theoilreturnoperationstartswhenthefollowingconditionoccurs:
• Whenthecompressorcumulativeoperatingtimewithrunningrotationspeedlessthan42rpsreaches6hours.
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Theoilreturnoperationceaseswhenanyoneofthefollowingconditionsoccurs:
• Oilreturnoperationdurationreaches5minutes.
• Compressorstops.
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Forheatingmode:
Component Wiringdiagramlabel Controlfunctionsandstates
Invertercompressor  COMP Runsatoilreturnoperationrotationspeed
DCfanmotor FAN Controlledaccordingtoheatingmode
Electronicexpansionvalve EXV 304(steps)
Four‐wayvalve 4‐WAY On
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MBT Confidential