02 Immergas — Heat Exchanger Overheating / Scale Buildup
At a glance
- Severity
- FAULT STOP
- Domain
- HEATING_SYSTEM
- Reference standard
- EN 15502 / PED 2014/68/EU
What it means
Heat exchanger temperature above the safety limit.
Probable causes
- Insufficient circulation due to slow pump or air in the system
- Primary heat exchanger clogged with limescale
- Safety thermostat defective or badly calibrated
- Flow temperature sensor faulty
Where to start
Measure flow and return water temperature. Is ΔT greater than 20 K?
Full guided diagnosis in the app
The diagnostic tree for this fault has 7 guided steps with measurements, checks and resolutions. You'll find it in HVACIQ, one of the five IndexOS apps: free, works offline.
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