41 codes
Heat pump error codes
Air-to-water heat pump codes from Mitsubishi Ecodan, Daikin Altherma, Samsung EHS and Vaillant aroTHERM plus, side by side. Low water pressure, low flow and a blocked outdoor unit are worth checking yourself; the refrigerant circuit and the electrics are a job for your installer.
MITSUBISHIHEAT PUMP
Common problems
What it's doing, the code each brand shows for it, and what to check first.
Same fault, every brand
Find the fault you're seeing, then your brand. Each code opens its own page with the checks and a verdict.
| Fault | Samsung | Vaillant | Daikin | Mitsubishi Electric |
|---|---|---|---|---|
| Low pressureThe water pressure in the heating system is too low or too high. | — | VaillantF022F723 | — | — |
| Water flow too lowNot enough water is flowing round the heating circuit. | SamsungE911E912 | VaillantF788 | Daikin7H-01 | MitsubishiL9 |
| Heating faultIt isn't heating properly. | SamsungE919 | — | DaikinAH-00AJ-03 | MitsubishiL8 |
| Temperature sensorA sensor can't read the temperature. | SamsungE904 | VaillantF514F585 | Daikin80-0081-00 | MitsubishiL5U4 |
| OverheatingIt got too hot and cut out. | — | — | DaikinAA-01 | MitsubishiL3 |
| Defrost problemIce is building up. | — | VaillantF741 | Daikin89-01 | MitsubishiL6P6 |
| Blocked airflowAir can't flow through the vent or duct. | — | VaillantF733 | — | — |
| Refrigerant or pressure protectionThe sealed refrigerant circuit is short of gas or outside its pressure limits. | — | VaillantF731F546 | DaikinU0-00 | MitsubishiLB |
| Fan motorA fan isn't turning. | — | VaillantF718 | DaikinE7-00 | — |
| Compressor or inverterThe compressor, or the electronics that drive it, has a fault. | — | VaillantF752 | — | — |
| Communication faultTwo parts of the system can't talk to each other. | SamsungE202 | — | DaikinU4-00 | MitsubishiE0-E5E6-EFE9J1-J8 |
| Control boardThe electronics or their wiring have a fault. | — | — | DaikinE1-00 | — |
| Power supplyThe electricity supply was cut or is out of range. | — | VaillantF1117 | DaikinA1-00 | — |
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344 codes from 24 brands, each one checked against the maker's own manuals and support pages.