Low
P3 on Worcester Bosch Greenstar 30HE

Your boiler is simply performing a routine internal startup check and will be ready to use in a few moments.

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

Please wait, initialisation in progress.

From this model's manual
Verified against the Worcester Bosch/Worcester Bosch Greenstar 25i Zwb 7 25 installation & service manual, page 45.
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 for 5 minutes to see if the boiler begins normal operation automaticallyIf the code persists, switch the boiler off at the fused spurWait 30 seconds and switch the power back on to force a fresh system reset

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

Avoid the next call-out bill

A cover plan would handle faults like P3: 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 fault codes

P1View →P2View →P4View →

All 25 fault codes on the Greenstar 30HE

Seeing a different code? Every code this model can display, in one place.

0.05.29.3A1A5A7A8ACAdb1C1C6d3E2E9EAF0F7FAFCFdP1P1, P2, P3, P1...P2

Related guides you might find useful

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →

New boiler cost 2026

Realistic UK prices for a swap.

Read →