52 Indoor unit and outdoor unit communication protection error diagnosis and solution (E1)Error Code E1Malfunction decisionconditionsIndoor unit does not receive the feedback from outdoor unit during 110seconds and this condition happens four times continuously.Supposed causes ● Wiring mistake● Indoor or outdoor PCB faultyMeasure Vs, is it positive fluctuation?(Vs is the voltage between S and N ofoutdoor unit. Red pan-S, Black pan- N)Measure Vs, is it positive fluctuation?(Vs is the voltage between S and N ofoutdoor unit. Red pan-S, Black pan-N)YesPower off, then restart the unit 2 minutes laterPower off, then restart the unit 2 minutes laterNoReplace the outdoor main PCB.Power on. Is the errorextinguished?Replace the outdoor main PCB.Power on. Is the errorextinguished?Check the outdoor wiring connectionCheck the outdoor wiring connectionReplace the indoor main PCB.Power on. Is the errorextinguished?Replace the indoor main PCB.Power on. Is the errorextinguished?YesReplace the outdoor main PCB.Replace the outdoor main PCB.NoReplace the indoor main PCB.Replace the indoor main PCB.NoCheck the indoor wiring connectionCheck the indoor wiring connectionYesYesCheck whether reactoris normal?Check whether reactoris normal?YesReplace the reactorReplace the reactor No