Sime Inconsistent DHW Temperature Control

Hot water temperature fluctuates between hot and cold during shower use

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

Partially blocked plate heat exchanger, Faulty DHW NTC sensor, Modulating gas valve issue, Incorrect flow rate through boiler

Safety first: Beware of sudden temperature changes that can cause scalding.

Check tap flow rate: Very high flow can exceed the boiler's capacity. Partially close the tap to reduce flow and see if temperature stabilises.
Clean shower head and filters: Remove limescale from shower heads and any inlet filters to ensure stable flow.
Engineer checks: The engineer should inspect and, if necessary, chemically clean or replace the plate heat exchanger, verify DHW NTC operation, and check gas valve modulation.

Medium 3/5

DHW Plate Heat Exchanger

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