Right bath shower mixer for combi boiler

[nbr]

Hi,

in the house I just moved in I have a combi boiler Ideal Logic ES35 (flow rate at 35C temp rise 14.5 l/min and specific rate of 16.9 l/min).

Water coming out of the upstairs bath shower mixer (attached) is *very* slow, to the point that I can't really have a shower or even wash the foam after a bath.

Any spec I should look out for if I wanted to change the bath shower mixer tap to have a better shower? I was looking at buying the following

Orchard Dulwich bath shower mixer tap

Click here to find out more about Orchard Dulwich bath shower mixer tap

victoriaplum.com

but I am being told by the builder I am using for renovation elsewhere in the house that I should get something that has less knees that the water needs to go through and instead has a direct connection from the tap to the shower. Something similar to this, designed for low pressure systems

Apollo Bath Shower Mixer with Shower Kit - Chrome at Victorian Plumbing UK

Shop the stylish Apollo Bath Shower Mixer with Shower Kit. Features a 1.5m shower flex. Now in stock and available online at Victorian Plumbing.co.uk.

www.victorianplumbing.co.uk

I am not sure at this stage if the limiting factor is the boiler and its flow rate or simply the type of tap. I wouldn't want to invest time and money to install a new bath shower mixer (with all the effort involved in installing and un-installing with the bath tub still present) to then still found the pressure on the shower is too low.

Note that the shower in the en-suite (other room from where the issue in question occurs) has good pressure (I wouldn't call it high but certainly not as bad as the shower in question).

 

[Elkato531]

The limiting factor will not be the boiler unless there is a fault. Have you checked whether you are getting the predicted performance at any of the hot outlets? Check for isolation valves/stopcocks not fully opened. Also check inlet filters to mixer (if fitted). Make sure shower head and/or spout diffuser are not blocked with scale.
You need to check pressure and flow rate of the mains supply to the property. Any mixer available should give a decent flow with a normal mains supply.

 

[nbr]

Pressure is ok in another bathrooms upstairs.

Stopcock all fully open and no massive limescale in the mixer in question (I removed the head and I get the same flow rate out of the cord itself).

It is as if that specific bathroom where the mixer in question is has low pressure.

Unless, as I say, it is down to the tap itself...