How much does it cost to fix Grant error code CH PUMP Slow flash?

Typical repair cost for the Grant CH PUMP Slow flash fault is £300-500 including labour.

CH PUMP Slow flash High

Grant CH PUMP Slow flash Fault Code

Q: What does the Grant CH PUMP Slow flash fault code mean?

Your boiler's central control board is struggling to signal the water pump, which means your heating may not turn on or circulate effectively.

Also written as CHPUMPSLOWFLASH — same fault.

The Grant CH PUMP Slow flash fault code means: your boiler's central control board is struggling to signal the water pump, which means your heating may not turn on or circulate effectively.. It appears on 5 Grant models in our database.

Technical description: Indicates a possible fault with the PCB relay. Replace PCB.

Typical repair cost £300-500 (including labour)

Engineer required

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

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Grant models that show the CH PUMP Slow flash fault code

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

Source

Grant CH PUMP Slow flash fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.

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