thermostatic shower / combi boiler / water pressure - help please!

[RTA18]

I am hoping to install a thermostatic shower (Grohe Grohtherm Bath/Shower Mixer Tap 34448000) in order to stop having a shower that is constantly going hot and cold! However, I am very worried that the water pressure - which is just fine (not brilliant, but fine) at the moment will then be reduced. I have a small combi boiler, in a first floor flat, the dial on the boiler has the pressure hovering under 1, if that means anything!

Anyone who can give me peace of mind that I am making a sensible move - or will I end up with a dribble of a shower? Is there anything I can do to make it all work better?

Thanks very much!
R

 

[nortonj]

The pressure reading on your boiler Has nothing to do with the pressure at the shower.
What's the pressure like on the old shower?
You need to check pressure and flow rates at the shower then look at the instructions to your new shower to see if their suitable.
Maybe the reason your shower goes hot and cold is a fault on your boiler?

 

[RTA18]

Thanks for the info!