Faulty shower valve or low pressure?

[neljan]

Hello,

I've never installed a shower before and I recently installed a thermostatic mixer shower purchased from Victoria Plumbing:

https://www.victorianplumbing.co.uk/milan-twin-modern-square-push-button-shower-valve-with-2-outlets

Its states that it's suitable for 0.5 - 5.0 bar but we have found that we only get a little trickle of water from the valve. The flow rate going into the valve is 12 litres per minute, would this suffice?

Here's a video of the issue:

Video:

Thanks for your advice

 

[oldbuffer]

1. You are confusing flow rate with pressure. You can get 12 lpm flow with virtually no pressure, given sufficiently low resistance to flow (large bore pipes, few fittings or bends).
2. If you have a cold water storage cistern (CWSC) in the loft and a vented hot water cylinder, you may well have less than 0.5 bar pressure. With such a set up, pressure at the outlet will be roughly 0.1 bar for each metre of height between the open outlet and the water in the CWSC. With a CWSC in the loft, and a shower head immediately below the ceiling of the storey below, the pressure is likely to be less than 0.1 bar, which won't work the shower.
3. If you have a combi boiler, or you have mains cold to the shower and hot from an unvented cylinder, you shouldn't have any problems. If you do, suspect very low mains pressure or a shower fault.
4. I'd suggest measuring the pressure of both hot and cold at the point they go into the shower valve, for which you will need a gauge, such as Screwfix 82412. You would also need a fitting to allow this to connect to the 15 mm plastic pipework, e.e. Screwfix 82086 and a plain pipe insert.
5. You have a lot of unclipped pipework behind what will, presumably be a tiled type finish. Furthermore, you have a lot of push fit elbows, which are not really a good idea in what will be an inaccessible area. If you are able to, you might save yourself a lot of future grief by re-piping in copper with soldered connections, and clipping the pipe work to the back wall.