Mitsubishi Ecodan fault codes
What each code means, from Mitsubishi Ecodan's own service literature, and which UK models it applies to.
Mitsubishi Ecodan heat pumps
E8Indoor ↔ outdoor unit communication error8 modelsE0Remote controller communication error8 modelsP6Plate heat-exchanger freeze protection16 modelsP8Refrigerant circuit abnormality8 modelsF5High-pressure switch (63H) operated8 modelsUFCompressor over-current8 modelsU3Discharge thermistor (TH4) open/short8 modelsU2Abnormal high discharge temperature8 modelsU4Outdoor thermistor open/short8 modelsU8Outdoor fan motor abnormality8 modelsU9Supply voltage abnormality (over/under-voltage)8 modelsL3Circulation water overheat protection (≥80 °C)44 modelsL4DHW tank overheat protection (THW5 ≥75 °C)44 modelsP1Room temperature thermistor (TH1A/TH1B) open/short44 modelsP2Liquid refrigerant thermistor (TH2) open/short44 modelsL5Water-circuit thermistor (THW1/2/5/6/7/8/9) open/short44 modelsLDBoiler flow/return thermistor (THWB1/THWB2) open/short44 modelsL6Circulation water freeze protection44 modelsL8Heating operation error (no temperature rise)44 modelsL9Low primary flow detected by flow sensor44 modelsE4Main controller communication failure (FTC receives nothing)8 modelsE3Main controller transmission failure8 modelsE5FTC transmission failure8 modelsE6Indoor/outdoor communication failure (reception)22 models
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