Low
P 0.9 on Potterton Powermax HE

Your boiler has noticed that the water pressure is getting a bit low and needs a small top-up to keep running efficiently.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

System pressure is falling. It is advised to top up the pressure (status display will flash).

From this model's manual
Verified against the Potterton Powermax He installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the water pressure inside your heating system drops below the ideal operating level. The most common reasons are small leaks from radiator valves, air being released through the vents, or the expansion vessel losing its air charge over time.

This issue is frequently seen in autumn when the heating is turned on for the first time after summer, as the change in temperature can highlight minor leaks or trapped air.

DIY fix possible

Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.Slowly open the valve(s) until you hear water entering the system.Watch the pressure gauge and close the valves tightly once it reaches 1.5 bar.

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Avoid the next call-out bill

A cover plan would handle faults like P 0.9: no call-out fees, no surprise bills.

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