Hoval Inconsistent DHW Temperature

Boiler provides hot water but temperature fluctuates between hot and cold during shower

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.

Possible Causes

DHW plate heat exchanger partially blocked, DHW flow sensor sticking, Inadequate cold water pressure, Thermostatic mixing valve malfunction

Safety: Risk of scalding. Test water temperature carefully.

Stabilise flow: Avoid opening multiple taps simultaneously. Keep a steady flow at the shower.
Clean DHW filters: Remove and clean any inlet strainers on the cold water supply to the Hoval boiler.
Service plate heat exchanger: Have a technician descale or replace the DHW plate heat exchanger if limescale is suspected.
Check mixing valve: If a separate thermostatic mixing valve is installed, service or replace it if it fails to maintain stable temperature.

Medium 3/5

DHW Plate Heat Exchanger / DHW Flow Sensor

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