Fault 59 202 Medium

Worcester Bosch Fault 59 202 Fault Code

Also written as FAULT59202 — same fault.

The Worcester Bosch Fault 59 202 fault code means: your solar heating system isn't circulating fluid properly, which means the sun's energy isn't being transferred to your water tank as it should.. It appears on 2 Worcester Bosch models in our database.

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: Mass flow rate in solar system for collector group 1 is too low.

What causes the Worcester Bosch Fault 59 202 fault?

This fault happens when the sensors detect that the solar fluid is moving too slowly or not at all through your roof panels. The most common reasons are a failing circulation pump, a blockage in the pipework, or the solar fluid becoming too thick and degraded over time. Without proper flow, your system cannot safely transfer heat from the sun to your hot water cylinder.

This fault is frequently triggered during the first warm days of spring or summer when the solar system is required to work harder after sitting stagnant over the winter.

Typical repair cost £120-350 (including labour)

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 →

Worcester Bosch models that show the Fault 59 202 fault code

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

Source

Worcester Bosch Fault 59 202 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