Worcester Bosch Combination Flow Rates Explained

Will a Worcester Bosch combination Boiler (or any other Brand of Boiler) increase or improve your water pressure or flow rate (sometimes referred to as flow volume) ??

The answer is NO

What the water pressure?

Water pressure is the ‘force’ of the water as it enters your property. Water Pressure is measured in Bars. The average water pressure in London is between 1bar and 1.8bar.

What is ‘flow rate’ ?

Flow rate is the amount of water coming out of your tap within a specific amount of time. Flow rate is usually measured in ‘litres per minute’ simply put how many litres of cold mains water have flowed out of your drinking water tap (at kitchen sink) or an external garden tap.

I want a combination boiler that will provide enough hot water simultaneously for 2x showers, which combination boiler will do this ?

In order to run 2 or more showers and/or taps simultaneously, you need a min of 20 litres per minute flow rate at the cold water incoming mains supply. In order to identify which combination boiler is the most appropriate, you need to understand how combination boilers heat up hot water.

Each Combination Boiler (doesn’t matter about the make/brand or model) has a hot water capacity, e.g. the Worcester Bosch 38cdi Combination boiler has the capacity to heat up 16.4 litres per minute.

Does this mean that if you buy a Worcester Bosch 38cdi Combination then the boiler will give you 16.4 litres per minute of hot water ?

The answer is NO

Imagine you have a flow rate of 12 litres per minute at your kitchen sink tap and outside garden tap. Let’s see which boiler is best for you.


flow rate worcester bosch combination boiler