Pressure loss in upstairs hot water taps

[NickL]

Recently moved into a house and have noticed that the upstairs hot water taps lose pressure once they're on. No matter how much I turn the tap if I leave it on the flow will eventually stop.

I've checked the boiler pressure and it's as should be and have made sure the stop cocks are fully open. Does anyone have any idea why this is happening and if so have any ideas as to how I can go about fixing it?

Many thanks,

Nick

 

[45yearsagasman]

The boiler pressure has little or nothing to do with the pressure at the taps.
Describe your system, boiler type and cylinder type (if you have one)

 

[NickL]

I have a Vaillant combi boiler, the room with the issues is directly above the boiler, the hot water pipe comes directly from the boiler to kitchen sink taps then is split to the bathroom above (bath, shower and sink) and down to the shower/sink in the basement. Not quite sure if I have a cylinder?

Here's a picture of the boiler:

 

[45yearsagasman]

If the downstairs taps are ok then I would be firstly checking each affected tap for internal faults. Unlikely to be a blocked supply. Some taps will close off on their own when worn through worn internals. Thats a combi, so you would likely have no cylinder.

 

[NickL]

Thanks will take the taps off and take a look, my initial thought was that it maybe trapped air but i'm not quite sure how to check/fix trapped air?