Bathtub mixer with thermostat- lost water pressure

[Va_Dub]

Hi All,

Hope all are doing great.

I have replaced two separate tap of my bathtub by mixer tap with thermostat.
Previous with two separate tabs, water pressure was strong, but after replacing it by mixer tab with thermostat, the water pressure has lost drastically (in tab as well as shower head) and shower head hardly get water out.

Any suggestions? How I can increase water pressure?

I have already checked, there is no water flow restrictor in shower head.

There is non return valve at mixer inputs, can I remove it to increase pressure? Are there any drawbacks of doing so?

 

[ShaunCorbs]

What’s your set up eg combi boiler / mains pressure hot or cylinder and cold water tanks ?

 

[Deleted member 120897]

As above, and did you check the suitability of the new taps and system?