Riello
Unstable DHW Temperature Control
Domestic hot water temperature fluctuates or runs hot then cold on a combi boiler
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
Scaled plate heat exchanger, Faulty DHW NTC sensor, Partially blocked DHW flow sensor or turbine, Inadequate flow rate through boiler
How to Fix / Troubleshooting
Safety: Risk of scalding from sudden hot water. Warn users and avoid maximum temperature settings until resolved.
- Check flow rate: Ensure taps are fully open. Very low flow can cause temperature swings.
- Clean inlet filters: Some Riello combis have strainers on the cold inlet. Isolate water, remove, and clean any debris.
- Descale plate exchanger: In hard water areas, the DHW plate heat exchanger may need chemical descaling or replacement by a technician.
- Sensor replacement: If the DHW NTC is giving erratic readings, replace it with a Riello-approved sensor.
Advertisements
Repair Difficulty
Medium
3/5
Required Part
DHW Plate Heat Exchanger
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements