Ha, no substitute fella. Trouble is I dont know anyone that Id trust to come and do the job properly now Ive seen all the bodgers at my house! Its hard when your relying on someone for something you dont know a lot about, learning quick mind... No doubt there are good lads out there and if you can help with someone in the N/west (Preston) Area then great.... If anyone wants some race motorcycle instruction round Oulton Park...... Jim...
Heat loss and system sizing is a tricky thing - as eaton says, it's part calcs, part experience. I'm struggling to see why there's such a disparity between your calculated losses and the 'rules of thumb' methods that eaton posted but without seeing your property and your calcs, it's difficult to see where the problem lies.
My gut feeling (and it's only a gut feeling, so as they say, it's worth what you paid for it !) is that your HP sizing probably isn't a million miles out, but there could be other issues which are causing inefficient running. This could include things like poor insulation which falls outside the calcs, draughts, poor system design (component selection, layout, piping, installation etc) or none of these and perhaps other things! My other gut feeling is that as discussed earlier, your underfloor installation isn't suited to HP use and that you might be better off with different emitters (high efficiency HP rads, fan coil units etc).
What I would say though is that I definitely wouldn't throw more money at the problem and start swapping things around until you've got a proper handle on what's happening with your system. However, it might be worth throwing a couple of hundred quid at an independent consultant who can do some calcs and take a look at your installation - the
Chartered Institution of Building Services Engineers would be a good place to start.
So you build race bikes? - Excellent! My racing days are over (I used to proddy race Yam LC's a long time ago) but I live in Cheshire and go past Oulton on my 'quick flirt out' route. These days I tour, mess with old bikes and display astonishing incompetence at trials (at 45 I don't bounce as well as I used to!).
Matt