Immergas Inconsistent DHW Temperature

Domestic hot water temperature fluctuates between hot and cold during 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

Scaled plate heat exchanger, Faulty DHW NTC sensor, Inadequate flow rate or fluctuating supply pressure, Modulation control issues

Safety: Risk of scalding from sudden hot water. Test water carefully.

Steps:

1. Check flow rate: Open the hot tap fully. Very low flow can cause instability; clean tap aerators and shower heads.
2. Avoid mixing at tap: Test with only the hot tap open; mixing with cold at the tap can confuse flow sensing.
3. Descale plate heat exchanger (technician): Remove and chemically descale or replace the DHW plate heat exchanger if restricted.
4. Verify DHW NTC and modulation: Technician should test the DHW sensor and gas modulation response.

Hard 4/5

DHW Plate Heat Exchanger

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