TradeAssistIQHome

Daikin Altherma fault JA-00

Malfunction of high pressure sensor

Heat pump

What it means

Refrigerant pressure sensor detects a value out of range (>4.5 MPa or <-0.05 MPa), causing the unit to stop operating.

Likely causes

  1. Faulty refrigerant pressure sensor
  2. Poor water flow through high pressure side plate heat exchanger
  3. Incorrect refrigerant charge
  4. High pressure switch confirmed faulty during checking procedure

Where to start

  1. Perform a check of the refrigerant pressure sensor
  2. Check high pressure side plate type heat exchanger for good water flow and heat exchange
  3. Check the refrigerant charge

The full answer, free

  • 9 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 52), right under the answer
Ask about JA-00 freeCreate a free account

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 Daikin manual for the Altherma. Check the model on the data plate before you order parts.

Other Daikin Altherma fault codes