I recently changed the hot and cold valves for a sink in an upstairs bathroom. The taps are mixer taps. All of the water for the bathroom (and indeed house) runs off the mains. Hot water is provided via a combination boiler.
The water pressure in the downstairs has not changed and is very strong. However, there is no very little pressure upstairs from the cold water. If I turn the sink taps on, followed by the bath taps, the sink taps stop.
There has been no impact on the hot water in any part of the house.
I think that there must be some sort of air lock upstairs. However I have no idea of how to eliminate it. I have turned on all of the taps upstairs, including the simultaneous flushing of the toilet. I have left all of the taps open for a considerable period. Nothing seems to work. I would assume (but we all know what that can do) that the mains pressure would force the air lock out. That’s if it is an airlock.
What started as a friendly gesture for an elderly neighbour, has become a nightmare.
Any help or suggestions would be greatly appreciated.