Worcester 28cdi ii - Hot water problem.

[Notaplumberbro]

Hi All,
I wonder if anyone could give me some advice regarding a Worcester 28cdi ii , I get hot water only at certain times when the central heating is on and even then the hot water is in short supply, there is a tank next to the boiler.
Is there a way of having hot water all time when needed?
Below are some screenshots from instruction manual:

Thank you

 

[ShaunCorbs]

Isn’t it a combi boiler ?

 

[Notaplumberbro]

Isn’t it a combi boiler ?

I think it is a combi boiler, I am not here for repair, but more for an advice if the boiler should dispense hot water at all times or only at certain times (which is what's happening at the moment). Thx

 

[John.g]

Can you post a picture of the tank adjacent to the boiler. Its a combi boiler but could possibly (but unlikely) also have a HW cylinder.
A combi will always dispense hot water, in limited amounts, when a hot tap is opened, a 28kw combi should give a flowrate of 7.4 LPM (from a mains temp of 6C) at 60C or 11.8 LPM at 40C.