We have a Chaffoteaux and Maury Britony combi SE.The central heating works a treat,sometimes it's too hot but we're not complaining. It's the pressure of water and temp that we are not happy with. The bath,bathroom sink and kitchen sink take an age to fill plus hot water not hot enough. Bar circle numbered 0 to 4,3 red dashes between 0 to 1.5,red line between 3 and 4. Indicator at 2. When it was first installed,no problems,what should I be doing to increase pressure,and how high can it safely go? How can we also raise temp of hot water?