When installing any cold-mains fed appliance it is important to ensure upfront that your water main is large enough to deliver adequate water to the appliance whilst other cold outlets are in use, for example flushing toilets, washing machine filling or cold taps being run. Should the water main be insufficient, you may find that cold water is 'pinched' from the boiler when more than one outlet is used. You could reduce the chance of this happening by giving the boiler priority over all the other outlets, by piping it up as the first draw off from your mains. The performance of any mains fed hot water system will depend on the mains water supply offering an adequate dynamic pressure and flow rate, as the flow rate must be sufficient to supply hot and cold water simultaneously. Whilst there may be sufficient mains pressure the flow rate is dependent on the size, type and condition of the incoming main. It is important not to confuse pressure with flow and the dynamic pressure will be less than the static pressure. Please see the technical specification for individual appliance mains water requirements. A water pressure reducing valve may also be required to protect the appliance from excessive incoming mains pressure. Maximum incoming water pressure is normally 10 bar.