Joule Modul Air fault 71

Over-temperature flow protection triggered

Heat pump

What it means

If the water temperature in the system exceeds the pre-set value (75°C), the over-temperature reset button may need to be reset. Error code 71 on the Modul-AIR signals this condition.

Likely causes

  1. Water temperature in the system exceeded the pre-set value of 75°C
  2. Central heating system not properly vented (air present in system)

Where to start

  1. Check whether the central heating system is properly vented by operating the manual air vent on top of the Modul-AIR and starting the venting cycle
  2. Confirm if only water comes out of the deaerator (properly vented) or if air also comes out (needs re-venting)
  3. After reset, check if sensor error 71 has been resolved - this can only occur when the water temperature has reduced by a minimum of 10K

The full answer, free

  • 5 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 100), right under the answer

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 Joule manual for the Modul Air. Check the model on the data plate before you order parts.

Other Joule Modul Air fault codes