Does low water pressure affect a combi boiler in Glasgow?

Yes. A combi relies on the incoming cold-water supply to provide domestic hot water on demand. If the incoming flow or pressure is poor, fitting a larger combi will not necessarily create a stronger shower or faster bath fill.

This is why water performance should be checked before choosing the appliance. A boiler's quoted hot-water capability assumes that the property can actually supply enough water to the unit. In some Glasgow flats, especially converted or upper-floor properties, incoming performance can vary and should not be guessed.

If hot-water performance is an important reason for replacing the boiler, ask for the mains supply to be assessed during the survey. Doherty's Glasgow boiler service specifically considers water flow and household hot-water demand before recommending a boiler type.