Medium Warning
9.1.7 on Ideal HP290

Your heating system is having trouble measuring the temperature for your second heating area, which often means that specific zone won't warm up correctly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Central Heating Zone 2 Thermistor Fault.

What causes this fault?

This fault occurs when the boiler loses communication with the temperature sensor dedicated to your second heating zone, such as an upstairs circuit or underfloor heating area. The most common reason is either a physical failure of the internal sensor component or a loose connection in the wiring that prevents the boiler from monitoring how hot the water is in that specific part of your home.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

9.1.6View →9.1.5View →9.1.8View →

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