# Underfloor Heating Layout

Rubbish Ben, you've clearly never done any UFH design. Of course you can give a wattM2 of any floor,
Without knowing the differential temperature?
And by the way, it's either

W/m2 not wM2, or
Wm-2

".....Whatever figure you want to use here is even more theoretical than normal heatloss calculations
"

No, not if you stick to MI's which are always held up by gas guys in other threads as Holy Writ.

Rubbish Ben, you've clearly never done any UFH design. Of course you can give a wattM2 of any floor,
Without knowing the differential temperature?
And by the way, it's either

W/m2 not wM2, or
Wm-2

Ben son, that's why the mean water temperature is used. No offence mate, but you don't have a clue. The floor outputs are always calculated on mean water temperature, with the Delta T adjustments made when the system is commissioned.

florad never got back to me, when I asked then to explain their choice of 10mm vs 15mm. Nor where they willing to update the diagram to reflect the heat loss from the large 5Mx2.3M glazed unit.

The builders have ageed to fit the 15mm pipe I have provided - it's a 5 layer 15mm pipe, with 50 years warranty and 10 years insurance (pipeplus). So that problem is resolved.

I've written up my thoughts on 10mm vs 15mm and started another thread, interesting to see if people think I have my assumptions right or if I missed anything.
//www.diynot.com/forums/viewtopic.php?t=266489

i've done my own diagram. It's te same floor space per circuit, so shouldn't alarm the builders too much. Obviously it's just a sketch and spacings and stuff aren't accurate.

that's why the mean water temperature is used.
The mean temperature in heating is as likely to happen as the temperature in central London will be exactly 12 degrees tomorrow all day. (which is the actual average for London tomorrow )

Which is exactly what I said; it is arbitrary because it is based on averages.
Your calculated 100W in theory, can be 130 in reality, or 70 of course.

It is exactly the same principle as why the theoretical 1734W of a normal rad, will always be considerably more, or considerably less when working under normal household conditions in stead of in a test-lab.

The big difference of course that a change in room temperature from 18 to 22, only changes the differential by 8%, with normal rads.
The same shift with ufh obviously moves the differential by more than twice that in even the most optimistic conditions; quadrupled is quite possible when the conductivity of the medium is just a tad lower than expected, the tuning off by just a fraction, and a handful of other items that tend to be changed by the users depending on what mood they are in.

I don't think you'll go far wrong with that layout mdp. I'd close band the loops in front of the large glazed area. Also try to keep all the loops the same length as poss. That'll make it easier to balance/ commission the system at the manifold. Also try to keep your loops under 100M, then you can use a standard domestic 5-6M head pump at the manifold.
HTH

Of course Ben you'll never have Lab conditions on any install. But I don't know if you've ever installed UFH or more so lived in a house with UFH.

UFH is the best form of heating any home, believe me.

Ever since I lived in a house with ufh, I will install it no more than I will fit an Ideal.

Ever since I lived in a house with ufh, I will install it no more than I will fit an Ideal.

Well it must of been one of two things, electric or you installed it.....

What is really interesting is that your entire response to my example where practical application deviates from what you have googled was:
“you'll never have Lab conditions on any install”.
From there on you hid immediately behind your so called experience with ufh.

It's amazing how quickly you change the subject from practical facts to unverifiable claims. Nobody on this forum can say jay or nay to any number of designs, or installations either of us care to boast, which make such claims about as pointless as itemising a long list of “achieved” qualifications.

Surely, you don't agree with what I stated about the variation in differentials between normal rads and ufh, and are more than capable to point out exactly why I am wrong there, and how they are actually virtually the same.

Without your usual “ I have done this so many times for such many years before you were even born let alone worked in this trade” of course; just facts and figures would do nicely.

I don't think you'll go far wrong with that layout mdp. I'd close band the loops in front of the large glazed area. Also try to keep all the loops the same length as poss. That'll make it easier to balance/ commission the system at the manifold. Also try to keep your loops under 100M, then you can use a standard domestic 5-6M head pump at the manifold.
HTH
Yeah sorry ignore the sketchyness, I didn't have a cad tool to draw it, so the distances of centres is not illustrative. All centres will be even throughout. I will try to keep each circuit to around the same length. The previous cad drawing said it was about 70M per circuit I think.

The manifold was assembled today. It's larger than I was expecting, compared to the manifolds I've seen in other systems from photos found:

I'm also now wondering if the system really needed two pumps? 3 circuits 70M per circuit, 15mm pipe.... Is that because 10mm pipes need two pumps as the water is harder to push round? But now that I'm installing 15mm pipe this the case? Will keeping two pumps have any downsides?

The plumber arives tomorrow, I guess I'll find out then

hmm this one looks even more compact:

That looks tidy and professional. Looks like it has over heat protection also.
But no flow indicators!
How much though? Probably about £400.
Why don't you let the plumber do the plumbing and let Bob do the building.

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