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Hitachi Yutaki M & Yutaki S fault 70

Hydraulic alarm flow & water pump malfunction

Heat pump

What it means

Indoor origin alarm (Retry Stop Code P70) indicating water flow not detected in the hydraulic cycle or pump defective.

Likely causes

  1. Water flow is not detected in the hydraulic cycle
  2. Pump defective
  3. Pump not operating within operating range
  4. Air trapped in water pipes
  5. Clogged water strainer
  6. Water leakage causing moisture on pump surface

Where to start

  1. Check water flow in hydraulic circuit
  2. Check pump operation
  3. Check water pump operation

The full answer, free

  • 11 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 334), right under the answer
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Safety: Isolate the outdoor unit and any backup heater, and give the inverter capacitors time to discharge before you open the electrics. Anything on the refrigerant circuit needs F-gas certification.

From the Hitachi manual for the Yutaki M & Yutaki S. Check the model on the data plate before you order parts.

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