Mixing Pressure Problems

[John.g]

OK, thanks.
Picasso has had a good drop of Jamesons tonight so sketching not up to his usual standard but this is the way I would go if you don't want to modify to a 3 way thermostatic mixer, there isn't much involved, as I said previously, you can leave the existing by pass if you wish (less work)

and just do the other changes.

 

[Savdefriz]

OK, thanks.
Picasso has had a good drop of Jamesons tonight so sketching not up to his usual standard but this is the way I would go if you don't want to modify to a 3 way thermostatic mixer, there isn't much involved, as I said previously, you can leave the existing by pass if you wish (less work) View attachment 46533and just do the other changes.

Looks good, the only downside to that would be that (from what I've read) the system would be less efficient as the control system wouldn't be able to regulate temp. But at this point in time I'd take an inefficient system that works over an efficient cold one that doesn't.... I'll keep you up to date with temps as they fluctuate, and have a drop for me!

 

[John.g]

I wonder just how sophisticated UFH systems really need to be as the system is a big thermal store in itself and runs 24/7, so very slow to respond to any tweeking, also your boiler will be running with a very low return temperature (no rads) so will be quite efficient.
Even though I would like to see if the proposed mods will work I think the sensible way to go would be with a 3 way thermostatic mixing valve as you will be making pipework changes anyway and will just re use the existing manifold pump.

 

[Savdefriz]

Slowly Slowly Catchy Monkey

 

[John.g]

Excellent, the trick now is to try to figure out what is the heat input into your UFH to heat your house, don't know the Baxi heat output but whatever it is, it is more than likely that it can modulate down to 5 or 6 kw which in turn means that it should certainly just now ( 1C here in Cork) be running continuously to have any meaningful contribution to heating the house, is it?.

 

[John.g]

Any update on the above?.

 

[Savdefriz]

Any update on the above?.

It seems to be working of sorts. I think that the system is possibly too big and the flow of water too low to heat the house properly. I can get the rooms up to 21/22 but the circulating hot water never gets above 35. I suppose that this makes it more efficient, but it can't cope with sudden changes in temp! I managed to get the pressure balanced by a bit of trial and error, but I'm seriously thinking of buying myself a thermal imaging device so that I can see what's really going on!