Combi boiler gaining pressure, coughing hot taps & more!

[Foddette]

Hi

Our combi boiler is about a year old. There is a pressure gauge (began reading at 1 bar) & an equalizing valve (we have a power shower).

Recently the hot water taps have been coughing air randomly (not every time you turn it on), the cold water taps are all very low pressure & the power showers motor goes into overdrive.

I've checked the pressure gauge & it now reads at 2.5! What could the problem be & what can be done to fix it?

Ta!