Low Warning
Fault 41 / 103 on Worcester Bosch Greenstar CDi Compact

Your boiler has detected an electrical problem with the sensor that measures the temperature at the bottom of your solar hot water cylinder.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Temperature sensor T2 at bottom of solar cylinder faulty: Short circuit on the sensor lead (T2).

What causes this fault?

This fault occurs when the electrical signal from the temperature sensor at the base of your solar cylinder is interrupted or distorted. The most common reason is a physical short circuit in the wiring or a total failure of the internal components within the sensor itself, preventing the boiler from accurately monitoring solar heat levels.

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 →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →