To alter the stream of the water just it is in your interest turn the knob to alter the pressure inside the hose.

If the pressure inside the pipes is too low the water’s stream may be too weak to use it. If you are not happy about the low pressure of the water in your sink or shower, a plumber can easily fix it. If the pressure inside a iron pipe is too high and the copper pipe itself has cracks it may end up in a leakage. We offer to solve problems with low pressure and high pressure in the pipes in less than 20 minutes.

Weak flow of water may be caused by low pressure inside the pipes which can only be fixed by a licensed experienced plumbing specialist

The boiler may not be working properly as a consequence of low pressure, that being so it could conceivably be evidence of something more serious like a leak in the system. Water may not be running as a consequence of low pressure in the pipes which can be safely solved by a certified plumbing professional