How much does it cost to fix Grant error code PP6?

Typical repair cost for the Grant PP6 fault is £150-450 including labour.

PP6 High

Grant PP6 Fault Code

Q: What does the Grant PP6 fault code mean?

Your boiler has shut itself down because the internal gases have reached an unsafely high temperature to protect the system from damage.

The Grant PP6 fault code means: your boiler has shut itself down because the internal gases have reached an unsafely high temperature to protect the system from damage.. It appears on 2 Grant models in our database.

Technical description: Discharge gas overheat protection

What causes the Grant PP6 fault?

This fault occurs when the internal temperature of the combustion gases becomes too high, triggering a safety shutdown to prevent the boiler from melting or cracking. The most common causes are a failure in the pump preventing water from moving heat away quickly enough, or a build-up of sludge and debris that has blocked the heat exchanger.

This issue often surfaces during the first cold snap of winter when the boiler is suddenly required to run at maximum output for long periods.

Typical repair cost £150-450 (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 PP6 fault code

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

Source

Grant PP6 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