High
E119 on Potterton Promax System HE Plus

Your boiler has detected that the water pressure is too low for it to run safely and has shut down as a precaution.

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

Water Pressure Switch Not Operated (Primary water pressure is less than 0.5 bar)

From this model's manual
Verified against the Potterton Promax System He Plus installation & service manual, page 64.
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 internal sensor detects that there is not enough water inside the central heating system to operate safely. The most common reason is a gradual loss of pressure through a small leak on a radiator valve or because the system was recently bled without being topped up.

This fault is more frequent in autumn when homeowners turn their heating back on for the first time, as the change in temperature and manual bleeding of radiators often causes the pressure to drop.

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.

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