Fitting a boost pump

[swampydrill]

Was planning on getting fitted a booster pump for shower, probably 2-2.5 bar pump. Had a poor experience recently with a relatives Salamander pump that had seized, turns out the bathroom company did not fit a surrey flange type fitting on top of the cylinder and also did not adjust the water temp in the cylinder, 2 reasons that Salamander refused to change the pump out of warranty. I want to make sure this get fitted right, the first time so i am looking for a few questions to be answered if possible.
I have a vented system with a mixer shower which is around 10 yrs old, is it worth changing this from the start.
I had installed some isolation valves on the lines to the shower, this was done with compression fittings, is it better with no compression fittings in the lines from the cylinder to the shower.
My hot water cylinder is not massive, 140 litre, is this big enough in to feed a power shower running at say 2-2.5bar, this is a positive head system.
What is the better pump, Salamander or Stuart Turner, if Turner then is a brass pump better than an all plastic eco pump.

Any other suggestions welcome

 

[muggles]

Stuart Turner Monsoon are the best you can get IMHO

 

[flameport]

And get the brass one.

 

[muggles]

And get the brass one.

All Monsoons are brass

 

[swampydrill]

I was thinking of a Stuart Turner, will get a 2 bar one, need some advice on the other items please.

 

[flameport]

If the existing shower works, no reason to change it.
Some isolation valves can restrict the flow, get full bore types if that is a problem.
140 litres of hot water is plenty for one shower, the limiting factor is usually the cold water storage in the loft and how quickly that refills, as you don't want that to run out while using the shower.
Surrey flange is not essential, the main thing is to ensure no air is sucked into the pump.
Salamander have that temperature setting thing so they can avoid paying for any warranty claim - it's something which can never be proven.