Some boilers require external pumps to push water around the heating system. Combination boilers have built in pumps.
If water pressure is low in your bathroom shower pumps are ideal for boosting pressure (if you have a gravity system - usually a storage tank in your loft area).
At Navton (Shirland) Limited we sell a vast range of water boosting products for domestic use. If you would like more information please email us on firstname.lastname@example.org and we will be happy to assist you in selecting the right product for your home. We stock a variety of pumps from Grundfos, Stuart Turner and Salamander and many more.