Vokera Inconsistent Domestic Hot Water Temperature

Hot water temperature fluctuates between hot and cold when using a tap or 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

Partially blocked plate heat exchanger, Faulty DHW NTC sensor, Inadequate flow rate through boiler, Modulating gas valve not responding correctly

Safety first: Risk of scalding if water suddenly becomes very hot.

Check flow rate: Fully open the hot tap; if flow is very low, clean tap filters and check stopcocks.
Avoid mixing at tap for test: Run hot only to see if boiler maintains a stable temperature.
Engineer tasks:
- Descale or replace the plate heat exchanger.
- Test and replace DHW NTC if faulty.
- Check gas valve modulation and combustion.

Fluctuating hot water is often due to scaling in combi boilers, especially in hard water areas.

Hard 4/5

Plate Heat Exchanger

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