Fehlercodes: H07_ECOi_MF1

Alarm Code H07
Alarm meaning No-oil alarm
Alarm conditions

This alarm occurs when oil does not flow for a specified amount of time in tubing where oil flow constantly. (The presence of oil is detected by a temperature sensor.)

Judgment method:
Tcal (calculated by the formula below from the oil temperature) is compared with the discharge temperature. If Tcal is higher than the discharge temperature then oil is judged to be present.
If Tcal is lower than the discharge temperature, oil is judged to be not present.

Tcal={(0.0254 · T_oil · LP2 +0.0298 · T_oil · LP +0.8842 · T_oil –2.9953 · LP2 –11.091 · LP +436.94) +2.9953 · HP2 +11.091 · HP –436.94}/(0.0254 · HP2 +0.0298 · HP +0.8842)

Probable cause

Insufficient amount of oil in the system

  1. The length of system tubing exceeds the allowable tubing length.
  2. The difference in height between system units exceeds the allowable value.
  3. A large amount of oil was drained when a compressor was replaced.
  4. Oil has accumulated in a stopped outdoor unit and has not returned, as a result of refrigerant circuit clogging or valve leakage at the stopped outdoor unit.
  5. A valve (ORVR, BALV, BPB) in the oil circuit has malfunctioned, or there is clogging of the circuit (capillaries) which returns oil from the oil separator to the compressor.
  6. If an excessive amount or liquid returns to the compressor, oil foaming may increase oil discharge. The same occurs when the refrigerant proportion in the compressor is high at start, due to an open circuit in the crank case heater.
  7. Oil sensor disconnected or open circuit
  1. Check the tubing length and height differences.
  2. Check the operation of system circuit valves.
  3. Check that there is not an excessive amount of liquid return. (Check that there is no mechanical valve leakage.)
  4. Check the crank case heater (wintertime).
  5. Check that the oil sensor is not disconnected, and that the circuit is not open.
  1. If insufficient oil is a possibility, then charge with additional oil.
  2. If it is clear that a valve failure has occurred, replace the valve.