High
P0.1-0.4 on Potterton Powermax HE

Your boiler has switched itself off because the water pressure is too low for it to run safely.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Boiler off because pressure too low. Replenish CH system & purge air. Find leak(s) and repair.

From this model's manual
Verified against the Potterton Powermax He installation & service manual, page 39.
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 inside your central heating system drops below the minimum level required for the boiler to operate. The most common reasons are a slow leak from a radiator valve or pipework, or a loss of air pressure inside the expansion vessel which causes water to be expelled through the safety valve.

This issue is frequently seen in autumn when the heating is turned on for the first time after summer, as joints may have contracted or weeped while cold.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
Search the official register →

Avoid the next call-out bill

A cover plan would handle faults like P0.1-0.4: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related guides you might find useful