UFH - Supply and Return pipes...

[Mulberry View]

I have a UFH design, done by the company who'll be doing the screeding. They are able to supply quality components without the mark-up the likes of Continal et al enjoy.

 

But what of the Supply and Return pipes for the manifolds? We haven't bottomed out an ASHP design yet and ideally would prefer to kick this can a little further down the road if possible. Is it normal for these pipes to be placed in the screed to be considered later?

 

There is a manifold in the Utility Room, very close to the ASHP (no need for buried pipes?), plus one in the Kitchen and a possible third one for the first floor (I can't imagine that needs considering in the ground floor screed).

 

[Nickfromwales]

Why 2x manifolds? 
 

Just done 16 ports here, same manifold location, so doubt you need to spend out on the second setup.  

[Nickfromwales]

Sorry, 28mm pipes to the manifolds, which can be set into the top of the insulation. 

[JohnMo]

Do yourself a favour and do your own design - there is zero room balancing by design. The design is for multiple zones/multiple thermostats, not single or limited zones for ASHP.

 

Suspect you can easily delete a few loops by spreading pipes that transition through various areas.

[Oz07]

26 minutes ago, JohnMo said:

Do yourself a favour and do your own design - there is zero room balancing by design. The design is for multiple zones/multiple thermostats, not single or limited zones for ASHP.

 

Suspect you can easily delete a few loops by spreading pipes that transition through various areas.

How do you do your own if no knowledge. Is there a website or app?

[Mulberry View]

1 hour ago, JohnMo said:

Do yourself a favour and do your own design - there is zero room balancing by design. The design is for multiple zones/multiple thermostats, not single or limited zones for ASHP.

 

Suspect you can easily delete a few loops by spreading pipes that transition through various areas.

 

I tried to do a design myself, but getting the kinda complicated floorplan uploaded saw me fall at the first hurdle. Any tips? The space above has 3 ground level heights by the way.

[Mulberry View]

8 hours ago, Nickfromwales said:

Why 2x manifolds? 
 

Just done 16 ports here, same manifold location, so doubt you need to spend out on the second setup.  

 

I guess a second manifold was added due to the floor levels? The Kitchen is 600mm higher than main part of the building with the Utility etc and the Living Room (lowest on that plan) goes up another 400mm.

 

Would it be difficult to bleed with a manifold at the lowest point?

[Nickfromwales]

The loops are fine as is, just need to come back to the central manifold location, and obvs make that a bigger manifold as required.

[Nickfromwales]

1 minute ago, Mulberry View said:

 

I guess a second manifold was added due to the floor levels? The Kitchen is 600mm higher than main part of the building with the Utility etc and the Living Room (lowest on that plan) goes up another 400mm.

 

Would it be difficult to bleed with a manifold at the lowest point?

Ah, yes! Tired brain and long days atm, sorry.

[Nickfromwales]

2 minutes ago, Mulberry View said:

 

I guess a second manifold was added due to the floor levels? The Kitchen is 600mm higher than main part of the building with the Utility etc and the Living Room (lowest on that plan) goes up another 400mm.

 

Would it be difficult to bleed with a manifold at the lowest point?

Can the manifold at the 'middle' be raised to become the highest point of both sets of loops?

 

[JohnMo]

1 hour ago, Oz07 said:

How do you do your own if no knowledge. Is there a website or app?

I used loopcad via a trial app. UFH is very similar in a lot of respects to a radiator.  A radiator you size to the room heat loss and target room temperature, each room has a radiator of a suitable size for the heat loss/temperature and the system as a whole is just about balanced out the box.  The exact same applies to UFH, you size your loops in the floor to match heat loss and target temperature for that room.

 

You can fill the floor with pipes but it's a bit like sizing a radiator to fit your longest available wall - you wouldn't do that.

 

Can't see the dimensions on your drawings but guessing around 200m²(?).  If so we are about the same size and only 7 loops.  Our flow temps are also super low.

[Mulberry View]

41 minutes ago, Nickfromwales said:

Can the manifold at the 'middle' be raised to become the highest point of both sets of loops?

 

 

The ASHP is going adjacent to the Utility Room, top left corner of that plan. The manifold in the middle would be about 10-12 metres away from the ASHP and 600mm higher than the closer manifold. I'm not against doing it in one, but I guess the supply and return pipes will be reasonably long. This could be shortened if I can pass them under the internal walls (in the Marmox blocks), but not sure if that's senslble?

[Mulberry View]

35 minutes ago, JohnMo said:

I used loopcad via a trial app. UFH is very similar in a lot of respects to a radiator.  A radiator you size to the room heat loss and target room temperature, each room has a radiator of a suitable size for the heat loss/temperature and the system as a whole is just about balanced out the box.  The exact same applies to UFH, you size your loops in the floor to match heat loss and target temperature for that room.

 

You can fill the floor with pipes but it's a bit like sizing a radiator to fit your longest available wall - you wouldn't do that.

 

Can't see the dimensions on your drawings but guessing around 200m²(?).  If so we are about the same size and only 7 loops.  Our flow temps are also super low.

 

The whole house is 200m2, the ground floor is 140 ish of those m2's.

 

The quotes I had from Roth, Continal and at least 2 others, all seemed to go for 150mm spacing, is it just that they're a bit lazy?

 

I tried one of the softwares mentioned on here (don't think it was Loopcad), but I really struggled getting the plan properly laid out.

[JohnMo]

7 hours ago, Mulberry View said:

all seemed to go for 150mm spacing, is it just that they're a bit lazy?

150mm is fine, but filling just floor is lazy. A new build requires so little heat. 

 

Layout on software, you can simplify it a little by making the angle 90 degs between the two wings.

 

One manifold or two the supply and return will be similar lengths. I would aim to use one manifold. You will not need a pump and mixer on the manifold, so don't let anyone sell them to you. Just run supply and return in 28mm you will have zero issues. Would suspect heat loss is below well 4kW, do don't let anyone sell you a big heat pump. I had a 6kW and found it too big, so swopped it out to a 4kW last winter.

 

Note on your loops

A-1, move manifold in room and all pipes passing through room do the heating - delete dedicated loop.

A-2 and A-6 delete and use pipes passing through that area, spread them out instead of bunched up.

 

Pipes can be 100m long. Loops A-10,11 and 13 add up to less than 200m, so could be 2 loops instead of 3. But if using 1 manifold that may not be possible, however an optimised design may allow 200 or 250mm centres do then that room and room next it could reduce the loop count.

 

[Great_scot_selfbuild]

8 hours ago, Mulberry View said:

all seemed to go for 150mm spacing, is it just that they're a bit lazy?

This was my experience.

 

This was another aspect of our build I went around a lot on and struggled to do as much myself as I wanted (Loopcad has yet to release an Apple version and I am now a reluctant mac user…). I personally found Floor Heating Warehouse to be the best value for me (certainly compared to Continel, as one example), and I had 4 revisions to the design done (much of which was prompted by support from the ‘hub), as they had unnecessary loops in areas that could be covered easily by just the out and return lines for each circuit. I ended up settling on using the 150 spacing as I didn’t have enough time to go into the detail I wanted, or pay for a dedicated heat engineer. I found the Rob Berridge series on YouTube very informative, and briefly fell into a YouTube hole of deep-technical heat calculation videos. In the end I’m happy with the fact that I’ll be very likely to run low temp flow and have my ASHP running on tick over at (hopefully) optimal SCOP.

 

I’ve gone with a NIBE ASHP for info - and since doing do, I’ve come across a lot of people who have raved about them.

 

Another thread you may find helpful:

 

 

I’ve just added a couple of update photos of the ‘after’ to the thread before I started.

 

(@JohnMo - thanks for your comments / input to my install; most helpful!)

[Great_scot_selfbuild]

@Mulberry View if you need a UFH pipe stapler (depending on what the pipe is going down onto) then I currently have the BH one - In the Tool Loan section of the hub there’s also a decoiler available (essential item!)

 

[Mulberry View]

3 hours ago, JohnMo said:

150mm is fine, but filling just floor is lazy. A new build requires so little heat. 

 

Layout on software, you can simplify it a little by making the angle 90 degs between the two wings.

 

One manifold or two the supply and return will be similar lengths. I would aim to use one manifold. You will not need a pump and mixer on the manifold, so don't let anyone sell them to you. Just run supply and return in 28mm you will have zero issues. Would suspect heat loss is below well 4kW, do don't let anyone sell you a big heat pump. I had a 6kW and found it too big, so swopped it out to a 4kW last winter.

 

Note on your loops

A-1, move manifold in room and all pipes passing through room do the heating - delete dedicated loop.

A-2 and A-6 delete and use pipes passing through that area, spread them out instead of bunched up.

 

Pipes can be 100m long. Loops A-10,11 and 13 add up to less than 200m, so could be 2 loops instead of 3. But if using 1 manifold that may not be possible, however an optimised design may allow 200 or 250mm centres do then that room and room next it could reduce the loop count.

 

 

I've had a preliminary ASHP quotation which included a heat loss analysis. Keep in mind that no commitment has been made to any of this. This is the output of that in terms of heat loss. Seems high for a triple glazed Nudura house...

 

 

Then I noticed that they appear to have used "placeholders" in the construction materials section...

 

 

The standard Nudura blocks are 0.24.

 

The figures for the floor and roof seem off. I'm having 230mm PIR in the floor (I'm sure that'll be substantially better than 0.18). There are 3 large rooflights, but these are Vario by Velux triple glazed units (1.1 u-value I think)

 

I'll be very disappointed if I don't achieve sub 1.0 ACH, I'm looking for 0.5 really.

 

I don't want to go too far with this design as I'm not vested in them and don't want to end up too deep in obligation to them. The house will also have MVHR of course.

 

 

 

 

[JohnMo]

At 0.26 your wall insulation must be very poor. I would look to add 50mm or more externally, if the figures are correct. Floor is likely to be around 0.08 U value.

 

32W/m² is huge. Similar build to ours is closer to 15W/m² at -9. Heat loss at 7.3kW sounds excessive.

[Russell griffiths]

For some reason the nudura icf blocks have a poor u value, when in reality we know they are very good when coupled with good airtightness. 
all these spreadsheets don’t deal with common sense 

180m ground floor, nudura walls, eps in the floor rockwool roof, excellent air test. 
5kw Panasonic heat pump. 

[Mulberry View]

4 minutes ago, JohnMo said:

At 0.26 your wall insulation must be very poor. I would look to add 50mm or more externally, if the figures are correct. Floor is likely to be around 0.08 U value.

 

32W/m² is huge. Similar build to ours is closer to 15W/m² at -9. Heat loss at 7.3kW sounds excessive.

 

That's what I'm saying, those values aren't reflective of what is there. Even based on the standard Nudura figures of 0.24 for their blocks (keep in mind these were ordered before the new regs came in). I don't understand the technicalities, but ICF houses seem to perform differently to their relatively poor quoted u-values.

 

At least half of the building is going to be rendered and will receive a 30mm layer of EWI in the detailing. The Architect designed a 50mm battened service void on the inside, which I may do away with on the perimeter walls or replace with PIR, yet to be decided.

 

That "design" is very preliminary, perhaps should be taken at this stage with a pinch of salt.

 

The software I played with was Heatpunk, maybe I could try Loopcad.

[JohnMo]

3 minutes ago, Mulberry View said:

Architect designed a 50mm battened service void on the inside,

That also increases U value, I looked at additional PIR on our build but the difference between an unventilated air space and actual PIR is too small to worry about.