Low
204 on Worcester Bosch Greenstar i

Your boiler has temporarily paused heating because the water inside is already hotter than the temperature you have currently set.

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

System waiting, primary flow temperature above set temperature point

From this model's manual
Verified against the Worcester Bosch Greenstar I 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

Check if your heating or hot water thermostat is turned to a very low settingWait 10 to 15 minutes for the water to cool down naturallyIf the boiler does not restart on its own after cooling, turn it off at the mains for 30 seconds and switch it back on

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 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 →