How much does it cost to fix Potterton error code p < 0.5?

Typical repair cost for the Potterton p < 0.5 fault is £0-120 including labour.

p < 0.5 High

Potterton p < 0.5 Fault Code

Q: What does the Potterton p < 0.5 fault code mean?

Your boiler has stopped working because the water pressure in the system is too low.

Q: How much does it cost to fix Potterton error code p < 0.5?

Typical repair cost for the Potterton p < 0.5 fault is £0-120 including labour.

Q: Can I fix Potterton fault code p < 0.5 myself?

Locate the filling loop (usually two braided hoses or internal levers under the boiler)

Also written as P05 — same fault.

The Potterton p < 0.5 fault code means: your boiler has stopped working because the water pressure in the system is too low.. It appears on 1 Potterton model in our database.

Technical description: System pressure falls below 0.5 bar (Control display will warn/Burner control goes to safety shut-down)

What causes the Potterton p < 0.5 fault?

This fault occurs when there is not enough water inside your heating system to safely allow the boiler to fire up. The most common reason is a slow leak from a radiator valve or a pipe joint, but it can also happen if you have recently bled your radiators and didn't top the pressure back up.

This code is frequently seen in autumn when homeowners turn their heating back on for the first time after summer, revealing pressure drops that occurred while the system was idle.

Typical repair cost £0-120 (including labour)

DIY fix possible

Locate the filling loop (usually two braided hoses or internal levers under the boiler)Slowly open both taps/valves to allow water into the systemClose the valves tightly once the pressure gauge on the display reaches between 1.0 and 1.5 bar

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Potterton models that show the p < 0.5 fault code

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

Powermax HE Repair: £0-120

Source

Potterton p < 0.5 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