Help Installing

@Dawnwhite welome. Tado will give you wiring instructions whom you start the installation. For users on the community site you need to fully describe your system for users to help you.

@wateroakley is right. Your boiler is controlled digitally and you will need detailed instructions. Tado has a duty to give you that.
It is important to write to Tado Sales and ask them to send precise instructions. Do let them know if you have zone valves in your home, a hot water tank, under floor heating and it it is a large home.
If you have problems implementing that guide come back here and we will pitch in.

When you write 'old receiver, is this the Greenstar old receiver, or a Tado one, or one made by someone else? This is important @Dawnwhite - because the boiler's digital control wiring and set up menu has to be reassigned in the same step. This link identifies the installation guide: Greenstar 25-30 Si Compact ErP Installation and Servicing Instructions | Worcester Bosch. On pages 29-32 the wiring is set out for different modes. It is clear that there is a configuration panel built into the boiler which helps inform it how you intend to control it.

Now, not trying to duck - it is really important that we dont cause a fault on your boiler's motherboard, or mislead its CPU, or it could be forced into a fault. What specific model of receiver is it -and does it handle the thermostat duties, or is the entire programming function operating through that receiver?