Boiler calculations

[swblackwell]

HI all

I have a worcester 28I junior condensing boiler, lately especially when showering hot water temp seems down.

I understand mains in is colder, so i have tried throttling the hot to give the temperature rise a chance.

My question is as how do i know that the boiler is giving the best it can and working efficiently.

Here is some info, can some one tell me if im running ok

worcester condensing 28I junior
2yrs old
mains in (today) 6.4deg @ 15litres / min
DHW out 50 deg @ 8.5litres / min
Lots of mist from flue (as discussed in threads)

I can increase the DHW to 54 but the L/min reduces drastically.

Using an electronic Aqualisa mixer shower. (incase it has or needs a specific flow)

Central Heating works great BTW.

Also what cost should i expect for a service?


Thanks for the help

 

[JohnD]

edited

my mistake, you have already given the information.

please ignore.