How to turn OFF the pre-heat on your Worcester combi boiler to save 5-10%

You can save around 5-10% on your gas bill if you turn the 'pre-heat' off on your Worcester combi boiler
Combi boilers are often tucked away in far corner of the home and it takes a long time for the hot water to reach the taps. Some boiler manufacturers have added a 'hot water pre-heat' function to their boilers. This keeps a little hot water prepared in the boiler and so cuts down the time it takes for hot water to come out of the taps.
However it uses a lot of gas! The boiler will come on every 90 minutes and uses small amount of gas each time, but over the year can add up to around 500-750kWh (about 5-10% of the average household's gas bill) if it is not timed.
In this blog we cover turning off Worcester pre-heats. Most Worcester boilers come with the pre-heat turned on, so you will need to turn it off. Scroll down the page to find your make and model. If wait times are a real problem for you, we recommend you fit a device called a combi save instead. This restricts the water passing through the boiler until the water has reached temperature. It saves both gas and water!
Contents
- Worcester Greenstar 25-30 Si Compact and Greenstar CDi Compact
- Worcester Greenstar 24-28 i Junior
- Worcester Greenstar 25-30 Si - later model
- Worcester Greenstar 25-30 Si - early models
- Worcester Greenstar 29-43 CDi Classic Combi
- Worcester Greenstar 27-42 CDi Combi
- Worcester Greenstar i Combi
- Worcester 8000
- Worcester 4000
- Worcester Greenstar 24-30 Combi

1) Worcester Greenstar 25-30 Si Compact and Greenstar CDi Compact
Press the ‘ECO’ button (No. 3 on diagram - top left hand button next to the digital display) to display ‘ECO’ in the digital display. When ECO is displayed the boiler will be in ‘Economy mode’ and the pre-heat will be turned off.

2) Greenstar 24-28 i Junior
Press the ‘ECO’ button (No 6 on diagram - bottom right hand button) so that the light comes on. When the light is on the boiler will operate in ‘Economy mode’ and the pre-heat will be switched OFF.

3) Greenstar 25-30 Si – later model
Press the ‘ECO’ button (No 6 on diagram - bottom right hand button) so that the light comes on. When the light is on the boiler will operate in ‘Economy mode’ and the pre-heat will be switched OFF.

4) Greenstar 25-30 Si – early model
Press the ‘ECO’ button (H on diagram - bottom right hand button) so that the light comes on. When the light is on the boiler will operate in ‘Economy mode’ and the pre-heat will be switched OFF.

5) Greenstar 29-42 CDI Classic combi
Press the ‘ECO’ button (F on diagram - bottom right hand button) so that the light comes on. When the light is on the boiler will operate in ‘Economy mode’ and the pre-heat will be switched OFF.

6) Greenstar 27-42 CDi Combi
Press the ‘ECO’ button (H on diagram - bottom right hand button) so that the light comes on. When the light is on the boiler will operate in ‘Economy mode’ and the pre-heat will be switched OFF.

7) Greenstar i combi
Press the eco button (middle button under the digital display or No 4 on diagram above) for 1 second to switch between ECO and Pre-heat. When ECO shows in the digital display the pre-heat is switched OFF.

8) Worcester 8000 Life (not Style)
Press the eco button (No 5 on diagram) to turn the pre-heat OFF.

9) Worcester 4000
Press the Menu button (labelled no.6 on image above), using up and down buttons (labelled no.3 above) scroll down to DHW preheat and press 'OK' (labelled no.5). Scroll down to 'Off'. Press OK again and it will be saved. Press the return arrow (labelled no.4) to return to the main menu.

10) Worcester Greenstar 24-30 combi
Press the ‘ECO’ button (6 on diagram - bottom right hand button) so that the light comes on. When the light is on the boiler will operate in ‘Economy mode’ and the pre-heat will be switched OFF.
Can't find your boiler?
It is definitely a combi boiler? It will be a combi boiler if you do not have a hot water cylinder. If it is a combi boiler and your model is not showing, it is likely that your model does not have a pre-heat option.

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