Low pressure geysers, as the name suggests, do not hold pressure as it is an open system. Water is fed into the pipes through gravity feed. Should you wish to increase pressure, a booster pump can be installed along the hot water pipe which is fed from the geyser.

If water pressure is low on a high pressure geyser then you should check if the correct pressure control valve is installed, it should not be more or less than 400kPa. You can also check the mixing valve if perhaps debris has blocked the valve and is restricting water flow.