Low
1P4 on Ariston Alteas One

Your boiler has detected that the water pressure is getting low and needs to be topped up to keep running properly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Insufficient water — request filling (non-blocking)

From this model's manual
Verified against the Ariston Alteas One installation & service manual, page 37.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Locate the filling loop (usually blue levers or a small pull-down tap) underneath the boiler.Slowly open the valve(s) until you hear water entering the system.Watch the pressure gauge on the display until it reaches 1.5 bar, then close the valves completely.

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