Most manufacturers recommend that the water pressure should be between 1.5 to 2 bars. Your boiler’s pressure gauge probably also has a green zone and a red zone. If the reading is within the green zone, the water pressure is optimal.
However, it is best to always refer to your boiler’s manual because every model could have a different optimal operating water pressure.
If the reading is below 1.5 bars or in the red zone of the gauge, you may need to top up your boiler’s pressure.
This can be done quite easily. You simply need to let in more water from your mains supply to your system.