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Panasonic Aquarea T-CAP R32 fault H74

PCB communication error

Heat pump

What it means

When External PCB connection is selected 'YES' and no communication with External PCB micon occurs for 10 seconds and above. Abnormality judgment occurs after 1 minute operation started.

Likely causes

  1. PCB communication wiring fault
  2. Faulty PCB
  3. Connector fault
  4. Faulty connector connection
  5. Faulty indoor sub PCB

Where to start

  1. Confirm Force heater request ON by user OR auto turn ON by remote controller during error
  2. Check latest mode selection sent by remote controller (heat/cool/tank)
  3. Check if H74 happens and check connection at CN-PWR is normal; if NO, correct connection at CN-PWR

The full answer, free

  • 3 more checks in order
  • How to put it right, step by step
  • The manual page for this fault (page 185), 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 Panasonic manual for the Aquarea T-CAP R32. Check the model on the data plate before you order parts.

Other Panasonic Aquarea T-CAP R32 fault codes