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Hitachi Yutaki M & Yutaki S fault 78

Indoor-LCD RF communication failure

Heat pump

What it means

There is no communication for 1 hour with one or two RF receivers which are bound to the RF-Bridge.

Likely causes

  1. No communication for 1 hour with one or two RF receivers bound to the RF-Bridge
  2. Loss of RF communication with bound RF receivers for 1 hour

Where to start

  1. Check LED1 (Red) on PCB1 for Power status
  2. Check LED2 (Green) on PCB1 for Communication with inverter status
  3. Check LED3 (Yellow) on PCB1 for H-LINK transmission status

The full answer, free

  • 6 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 336), 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.

Other Hitachi Yutaki M & Yutaki S fault codes