BoilerFaultCodesGrant PP5 Fault Code
The Grant PP5 fault code means: your boiler's internal thermometer that measures the air around it has stopped working properly, preventing the system from operating safely.. It appears on 2 Grant models in our database.
Technical description: Ambient temperature sensor failure
What causes the Grant PP5 fault?
This fault occurs when the boiler's control system loses communication with the sensor that monitors the temperature of the air inside the casing. The most common reason is that the sensor has developed a physical defect or the wiring connecting it to the main control board has become loose or damaged.
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 →Grant models that show the PP5 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Grant PP5 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