BoilerFaultCodesYour boiler has lost the ability to measure the temperature of your tap water, meaning you will likely have no hot water until the sensor is fixed.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Domestic hot water (DHW) temperature sensor failure – possible error with electronic card or the NTC sensor.
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with the sensor responsible for monitoring your tap water temperature. The most common reason is that the sensor itself has developed an electrical fault or has worn out, though loose wiring or a failure on the main control board can also stop the signal from being received.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like E04 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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