BoilerFaultCodesYour boiler has stopped working because a sensor that monitors the temperature of the exhaust gases has failed or is reporting an error.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue negative temperature coefficient (NTC) fault
What causes this fault?
This fault occurs when the sensor responsible for monitoring the heat of the exhaust gases sends an incorrect or missing signal to the boiler's main control board. The most common reason is that the sensor itself has developed an electrical internal failure or the wiring connecting it to the system has become loose or damaged.
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.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E28 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
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.
Affiliate links — we may earn a commission at no extra cost to you.