Low
P.05 on Glow-worm Ultimate 3 25R

Your boiler is currently refilling its internal water system, which is a normal process that happens automatically if the water pressure has dropped.

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

Filling the product

From this model's manual
Verified against the Glow Worm Ultimate 3 25r installation & service manual, page 28.
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

Wait 5-10 minutes to see if the boiler completes the automatic fill process.Check your system pressure gauge; it should be between 1.0 and 1.5 bar.If the code persists for more than 30 minutes, check your external filling loop valves are fully closed.

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

Monthly cover means no unexpected bills when your boiler breaks down.

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 fault codes

F.22View →F.73View →

Related guides you might find useful

Boiler keeps losing pressure

Six most common causes of dropping pressure.

Read →

Low pressure — repressurise guide

Step-by-step using the filling loop.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →