Low pressure from new shower pump. Air Lock?

[fatbdk]

Hi all. I'm new here and hoping you can help me. I just had a shower pump replaced - like for like model. The pressure is really low, and actually the pump doesnt sound right - like its being strangled/under pressure. Because its exactly the same make and model we know how its should perform and sound, and something just isn't right.

I don't think there is any way to adjust the pressure on the pump so am wondering if it could be an air lock? The plumber had to drain the hot water to fit it.........

Any ideas really gratefully received. Thanks

 

[joe-90]

Are you sure that any isolating valves are fully open and no hoses kinked?

 

[fatbdk]

Hi Joe. All checked and looks ok. Thanks though