Worcester Combi 24 CDi LOW WATER FLOW FROM HOT TAP

[Q8LEE]

Hi, had this boiler for 6 years and its been great and I know these boilers have a good reputation.
My problem is that the hot water flow to the taps has diminished to 6 litres a minute. It should be 9 litres a minute. I know that the water flow cannot be adjusted and everything looks fine inside the boiler itself. I used to service boilers many years ago so I know a thing or two but would like a bit of advice before deciding anything.
Would greatly appreciate any guidance.
Lee

 

[scatmanjohn]

I know that the water flow cannot be adjusted

there is a restrictor on the diverter...little black square looking thingy