Your boiler has lost the ability to measure the temperature of your hot water, which usually means it will stop providing hot water or provide it at an inconsistent temperature.

Hot Water NTC Fault

What causes this fault?

This fault occurs when the internal sensor responsible for monitoring your hot water temperature has failed or is sending a broken signal to the main control board. The most common reason is that the sensor has physically degraded over time or developed a short circuit, preventing the boiler from knowing how hot the water is. In some cases, the issue may simply be a loose or corroded wire connection between the sensor and the boiler's computer.