Fault 51 133 Low

Worcester Bosch Fault 51 133 Fault Code

Also written as FAULT51133 — same fault.

The Worcester Bosch Fault 51 133 fault code means: your boiler's internal sensor has detected a communication issue with your solar heating system, meaning the solar panels aren't currently helping to heat your water.. It appears on 2 Worcester Bosch models in our database.

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 type PTC 1000 used as collector temperature sensor (T1).

What causes the Worcester Bosch Fault 51 133 fault?

This fault occurs when the boiler loses contact with the sensor located on your roof's solar panels. The most common reasons are a faulty temperature sensor or a break in the wiring that connects your solar thermal system to the boiler's control module. Without this communication, the boiler cannot determine how much heat is available from the sun and will stop using the solar system.

This fault is more common following extreme weather events, as high winds or heavy snow can damage the external wiring or sensor probes located on the roof.

Typical repair cost £90-160 (including labour)

Engineer required

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

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Worcester Bosch models that show the Fault 51 133 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch Fault 51 133 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026