BoilerFaultCodesPotterton Pressure Gauge 3 or greater Fault Code
Also written as PRESSUREGAUGE3ORGREATER — same fault.
The Potterton Pressure Gauge 3 or greater fault code means: your boiler has too much water inside it, causing the pressure to reach a dangerously high level where the safety valve must release water.. It appears on 1 Potterton model in our database.
Technical description: A pressure of 3 or greater indicates a fault. The safety pressure relief valve will operate.
What causes the Potterton Pressure Gauge 3 or greater fault?
This fault occurs when the internal water pressure becomes too high, often because the expansion vessel has lost its air charge and can no longer absorb the natural expansion of heated water. It can also be caused by a filling loop being left slightly open, which allows water from the mains to constantly leak into the system, or a split heat exchanger allowing cross-contamination.
This issue is most frequently noticed in winter when the heating is first turned on, as this is when the water undergoes the most expansion and puts the most stress on the expansion vessel.
DIY fix possible
Check that the internal or external filling loop valves are tightly closedSwitch off the boiler and allow radiators to coolBleed a radiator or drain water from a radiator drain-off point to reduce pressure to 1.5 barIf pressure continues to rise after draining, turn off the mains water stopcock and call an engineer
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Gas Safe Register →Potterton models that show the Pressure Gauge 3 or greater fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton Pressure Gauge 3 or greater fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026