A05
Beretta
Primary Circuit Overtemperature / Flow NTC Overheat
Boiler shows A05, burner stops, flow temperature very high, radiators may be extremely hot, fan and pump may continue running.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Blocked or scaled primary heat exchanger, Insufficient circulation due to partially blocked system, Pump running at incorrect speed or failing, Faulty flow NTC sensor giving incorrect readings
How to Fix / Troubleshooting
Safety: Allow the boiler to cool before working on it. Do not remove the combustion cover while hot.
- Check all radiator valves: Ensure enough radiators are open to allow proper circulation. Closing too many TRVs can cause overheating.
- Bleed system: Remove air from radiators and any high points. Air pockets reduce flow and cause local overheating.
- Check pump speed setting: If the pump has selectable speeds, ensure it is not set to the lowest setting on a large system.
- Technician – inspect primary heat exchanger: Remove and visually inspect the Beretta primary heat exchanger for scale or sludge. Descale or replace if necessary.
- Technician – test flow NTC: Compare NTC resistance to temperature charts. Replace the flow temperature sensor if readings are out of tolerance.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Primary Heat Exchanger
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements