USA Unvented cylinder - water pressure

[Tim0212]

Hi, looking for advice about unvented cylinder. I had one installed as part of a horrific modular loft conversion that was recently finished. The water pressure in the bathrooms is poor, probably worse than when just had combi and I cant use two showers/bathrooms at one time which was the point in having it installed. When first installed it seemed good but then there was a leak in the system. Leak was fixed but pressure now poor. The tested cold incoming measures at 22 lpm and 3 bar but when i check this in bathrooms its less than 8lpm. The plumber is refusing to return as loft company arent paying him(think theyre going under) and his only advice is that the incoming supply is the issue. Im not convinced though due to rate during test and i've recently tested outside tap and its 3 times quicker than inside. The new shower in loft occassionally has fluntuating pressure that you can see by eye. Does anyone have any advice?

 

[Riley]

What is the incoming supply? Size wise??

 

[Riley]

Have they upsized all the way to the point of the cylinder??

 

[Scott_D]

Any pics of the cylinder and pipework?

 

[Tim0212]

What is the incoming supply? Size wise??

The incoming supply has never been touched and has old stopcock so think its 15mm. The cold cylinder incoming was taken from the cold pipe under the stairs which is also 15mm (photo attached). From the first floor i believe they are all 22mm pipes up to cylinder which is horizontal in loft eaves.

 

[Tim0212]

Return pipes going back to combi

 

[Riley]

So incoming to stopcock is 15mm?? Not enough

 

[Tim0212]

Any pics of the cylinder and pipework?

Yeah, pretty tight in eaves space but got some photos. Thanks for responding btw

 

[Riley]

Is that a vertical cylinder tipped sideways

 

[ShaunCorbs]

That stopcock is going to reduce the flow

Also the cylinder isn't rated for horizontal install best get the plumbing firm back as install is not to regs also not fit for purpose