PPS - Gas Engineer and plumber in Brighton and Hove
You may need a new boiler because your current boiler is beyond repair or you just feel it's time for an easy problem free life (hot water and heating wise that is, I don't perform miracles!).
You want guaranteed hot water and central heating for you and your family with no issues. This is what I am here for, either to look after your current set up and be there if it breaks down and to service it once a year or install a new boiler that will suit your needs.
Now that may be a 24kW Viessmann combination boiler or a 35kW Worcester Bosch combination boiler. If you have opted for a combination boiler then these would probably be it. For a strong powerful shower or possibly two showers running at the same time then the bigger 35kW will be necessary.
On the other hand you may love baths and / or have a four bedroom house and during discussion with me have opted for a system boiler with a hot water tank in the airing cupboard. You are limited to the amount of hot water in the cylinder but you will get that water very quickly - like a 5* hotel, fill up the bath in 20 seconds!