Homeowners Professionals
Boiler Gareth Jones

How does a central heating pump work?

There are a lot of different elements to a heating system that are required to provide heat and hot water to your home. From the obvious things like boilers and radiators, to the things you rarely see like central heating pumps, all parts serve their own purpose.

A central heating pump in a conventional boiler system pushes water that’s been heated by the boiler through your home’s radiators, taps and showerheads. It’s usually located in or near the boiler or the airing cupboard and without this device, the hot water wouldn’t go anywhere. Read on to find out more about how this appliance works within your heating system.  

How a central heating pump works

A central heating pump works by pressurising the water with impellers and delivering this around the system to provide fast heat to your home.

Step 1: Water enters the system

Once the water has been heated by the boiler, it enters the central heating pump via an inlet.  

Step 2: The water is pressurised

Impellers are used to pressurise the water. These components look like the propellers on ships, only they are a much smaller version. When the impellers rotate, they push the water out from the centre of rotation. In doing so, energy is transferred from the motor to the fluid, thereby pressurising it.  

Step 3: The water is pushed through the outlet

Once the water is pressurised, it is pushed through the outlet that allows it to travel around your heating system. It’s thanks to the pump that you can feel your radiators start to warm up only a few minutes after your boiler has turned on.  

Step 4: The water returns to the boiler

As the heated water gradually cools down, the pump delivers it back to the boiler so it can be reheated for the whole cycle to start again.  


What does ‘Boiler Plus-compliant’ mean?

In order for a heating system to be compliant with Boiler Plus legislation, it must meet a certain set of key requirements. Boiler Plus specifies that:

  • Gas boilers fitted as part of an existing heating system are required to have an energy-related products (ErP) efficiency of 92% as a minimum.

  • Gas and oil boilers are required to have temperature and time controls fitted simultaneously, if they are not already in place and working correctly.

  • Replacement combi boilers must be accompanied by an additional energy efficiency measure which must be fitted at the same time. There are three additional measures that can be introduced - weather compensation control, load compensation and smart controls, such as smart thermostats.

What Boiler Plus options are there?

As mentioned in the section above, there are an additional four measures available to help installers ensure the combi boilers they install are compliant with the Boiler Plus regulations. These measures also give customers options on how to make their heating systems more energy efficient.

The additional energy-saving measures that can be used with combi boiler installation in order to comply with Boiler Plus are:

  • Weather compensation control

A weather compensation controller works alongside the boiler to lower the water temperature based on the temperature outside, increasing its efficiency without impacting comfort for the user. Consisting of a simple external sensor that feeds weather data to the boiler, this innovative functionality allows the boiler to retain a stable temperature by changing the output in relation to fluctuations in the weather.

  • Load compensation

A load compensation device works by calculating the gap between the current internal temperature and the user’s desired temperature. The device then regulates the boiler so that it only uses the right amount of fuel to close this gap in order to reach the ideal temperature without using excess energy. Load compensation is usually compatible with many smart controls - another measure that is compliant with Boiler Plus.

  • Smart controls

Smart controls allow you to remotely adjust the temperature of your home via a smart device, such as a phone or tablet. This feature automates the time and temperature settings, and it also works on a learned schedule of use and is able to detect how quickly your home gains or loses heat and how long it takes for the property to get to the optimum temperature.

It’s important to bear in mind that just one of these four options is needed with the installation of a replacement combi boiler.


Does my heating system need updating to comply with Boiler Plus?

All households are subject to the rules and regulations set out in the Boiler Plus legislation, meaning that any boiler that has been installed after April 2018 must comply with these standards. However, these requirements only apply if you are installing a new boiler, meaning there is no need to make any updates to your system unless you feel it is time to replace your current model.

The good news is, if you want to replace your boiler for a newer model, many modern designs are already Boiler Plus compliant, giving you one less thing to think about at installation. However, it’s always important to check if you need to select an additional measure, especially if you’re having a combi boiler installed.

At Viessmann, our Vitodens 050-W, 100-W and 111-W combi boilers and our Vitoden 200 Series boilers are fully compliant as standard, when connected with a weather compensation sensor. We ensure our Boiler Plus compliant models are easily recognisable by the DBSCG label on the box.  

Do smart thermostats comply with Boiler Plus?

Since smart controls is considered one of the four additional energy-saving measures for combi boiler installation, a smart thermostat should mean that you meet the requirements of Boiler Plus. That being said, it’s important to check that the thermostat model you’re interested in is recognised as being compatible with the Boiler Plus policy, as well as your heating system, before installation.


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