how to increase hot water flow in upstairs bathroom.

[ZakUK]

The hot water pressure is quite weak in upstairs bathroom and it doesnt hold the temperature: goes hot - warm - hot - warm etc.
I'd like to change shower head into big round one, but i doubt id get a proper water flow through it.
The perfect scenario would be to be able to install big round shower head and have a strong stream going through it.

Is there a way to achieve it ?

i've got Vaillant combi.

thx

 

[steve32]

No not with a combi