Ufh, look at these plans please.

[Russell griffiths]

NR1620 Russell Griffiths PIPE LAYOUT REV A - FINAL COPY - A1 (46 High Street).pdf

 

 

I have just had this design back and there is a bit I’m not happy with, now don’t look at all of it yet as there is a few things wrong that I have already notified them of, it’s the bit I’m about to mention I would like us to concentrate on, now I’m not a heating expert in any shape or form, but I do have a phd in common sense. 

So before I have a whinge I thought I would find out if I’m being stupid. 

 

If you look at the stairs there are 4 flow and returns all next to each other, now if these where spaced 100mm apart then surely the loops in the lounge would not need to be so long, and then when they turn left to return to the manifold they would fill up the hall, so no pipes needed in the hall. 

 

Tell me im mad or wrong, I can take it. 

[JamesP]

Hi Russell, 

 

I see the boot room and study will have  a separate thermostat to the main room hence the loops are run very tight to the wall so they do not effect the output of your lounge if you turn off RS3.

I had 5 long loops to the kitchen / dining. Not a problem.

Very pleased with Wunda.

 

 

 

Edited June 5, 2020 by JamesP

[ProDave]

Forget the UFH loop in the hall.  In our previous house on the advice of the UFH designer we had a loop in the hall and one on the landing.  The landing one NEVER came on, and the hall one only very rarely.  Total waste of pipe and effort.

 

Instead just space out all the pipes that are passing through the hall. That will be all the heating you want in the hall.

 

Why no UFH in the bathrooms?  It is really nice to have a warm floor in the bathrooms.

 

If you can pass pipes under the internal walls you can get some much better pipe runs  Why only go through doorways?

 

I take it the room left of the kitchen is a pantry hence no UFH?

 

I am surprised bed 1 needs 2 loops I would be tempted to make that just one, that is another less port on the manifold and less congention in that hall.

 

In the kitchen, I can see why you want no heating under the units but I would pass the pipes to and from loops 1-10, 1-11 and 1-12 under that peninsular run of units just to save the congestion going around the units.  Just insulate the short sections of pipe going under the units.  And if those same runs could go through the "NO UFH" room (with insulation) then that gives them a very much more direct route to the manifold.

[JFDIY]

Looks like it wants to be on two manifolds to me, lots of long loop lengths in that.

 

Eg. Loop 1-1 goes all the way around the edge of the first room when you could cut a groove in the insulation and pass straight across and under the other loop and save 10m of loop length

[JamesP]

The reality of using a 12 port manifold will fill at least half the hallway, I agree with @JFDIY about using two manifolds, It would reduce the long lengths. You have over 1100m of loops to fit and will have some excess from each.  The 16mm pipe is a bit of a wrestle.

As @ProDave says, I would run a simple loop into each bathroom from the bedrooms.

 

[Russell griffiths]

Thanks all, all the points you have raised I have already had a chat with them about. 

 

I need a bit more education so I can plan this better. 

 

Is there a good length of pipe run to aim for, what’s too long. 

 

Should pipe lengths be as even length as possible. 

 

If all runs are a good length, why would it be better to have two manifolds, with a second manifold, I would then have to run a flow and return to that. 

 

 

One question I have is the long runs from the manifold to the rooms is all congested together, so why can these not be spaced the same as the loops in the room by spacing the runs apart they would cover a large floor are and then less loops needed to cover that area. 

 

Does that make sense. 

 

 

 

[willbish]

1 hour ago, Russell griffiths said:

 

Is there a good length of pipe run to aim for, what’s too long

I think 100m is the approx maximum. A little bit over seems to be okay.

 

1 hour ago, Russell griffiths said:

 

Should pipe lengths be as even length as possible. 

Yes as much as possible but some variation inevitable.

 

1 hour ago, Russell griffiths said:

 

If all runs are a good length, why would it be better to have two manifolds, with a second manifold, I would then have to run a flow and return to that. 

Your manifold is fairly central so I see no reason for a second manifold.

 

1 hour ago, Russell griffiths said:

One question I have is the long runs from the manifold to the rooms is all congested together, so why can these not be spaced the same as the loops in the room by spacing the runs apart they would cover a large floor are and then less loops needed to cover that area. 

Exactly what I did, but some bunching was still required especially if you can't/don't want to run pipe under internal walls.

I'll try to dig you out a copy of my DIY plan. It's a bit simpler than your set up because the UFH is in the raft fountain. I also went for even coverage under the whole ground floor and my internal walls were blockwork so ignored internal layout when designing the layout.

Edited June 6, 2020 by willbish

[PeterW]

What’s the Delta- T and output temperature they have designed it to ..?? Screed depth and material..??

 

150mm is quite tight for some of those loops - I would look at 200mm centres and run it lower temperature for longer.

 

Like others - need it in the En-suites and a lot to be gained from using the individual flow and return pipes in hallways etc. 
 

Loop lengths are irrelevant, they should be roughly equal where heating the same room, but use the auto balancing actuators and 99%

of the problems go away. 

[Nickfromwales]

Stick to one manifold. As long as the runs are 100m or less you’ll be perfectly ok. 
As peter says, ask Wunda for the auto balancing actuators and you don’t need to do any commissioning whatsoever. Just plug and play, and go to the pub. 
Where the pipes are congested, just insulate the flows and leave the returns bare. 
If you’re on an ASHP then stick to 150mm centres to keep the water volume high. 

[Nick Laslett]

4 hours ago, Nickfromwales said:

...
If you’re on an ASHP then stick to 150mm centres to keep the water volume high. 

 

I wondered about this on the spec sheet of the ASHP I was interested in.

 

This was the Panasonic WH-MDC07H3E5

 

Spec sheet: Water Flow rate 17 l/min (17 litre per minute)

 

Is this the ideal target, or maximum or minimum. The text of the Spec sheet has no further details.

Edited June 6, 2020 by Nick Laslett

[ProDave]

ASHP's do need a high flow rate, 17L/min does not surprise me, mine has a minimum flow of 15L/min and I only achieved that by putting a second circulating pump in.

[Nick Laslett]

13 hours ago, ProDave said:

ASHP's do need a high flow rate, 17L/min does not surprise me, mine has a minimum flow of 15L/min and I only achieved that by putting a second circulating pump in.

 

Thanks, that is good to know. 

 

In Loopcad, changing from enforced Delta-T calculations to automatically calculated by the software, changed the flow rate on my design from 14L/min to 22L/min.

[PeterW]

Yes but I expect the dT is something like 8c based on 45/37 which is the hot end and traditional flows. It is also designed to get the room temperatures up within 60 minutes from memory - there is a set of parameters hidden somewhere and you can alter these. 
 

If you’re using ASHP as a heat source then you really want to be using E7 and overnight - slab on at 3:30am to absorb low grade heat for 3 hours etc.  That needs a lower flow temp and closer to the final room / slab temp you’re looking for so ideally it’s nearer the 35c flow (most ASHP have 35c as optimum for CoP) blended with the return water. 
 

18 hours ago, Nick Laslett said:

Spec sheet: Water Flow rate 17 l/min (17 litre per minute)

Ignore that entirely !! That’s the flow the ASHP needs, not the floor. The floor flow is set by the manifold circulation pump, not the ASHP pump and it’s a bad idea to just connect the ASHP to the manifold and hope it runs ok as the zones closing will play havoc with the flow. 
 

I’d use a small buffer  - 60-100litre - and let this do the balancing to the ASHP. The heat pump then uses the tank stat on the buffer to fire rather than the call for heat from the UFH controller as it is less likely to short cycle or find flow restricted. 

[Russell griffiths]

Thanks everyone, I’m going back to the drawing board with this, so many things to change. 

 

 

[Nick Laslett]

10 hours ago, PeterW said:

Yes but I expect the dT is something like 8c based on 45/37 which is the hot end and traditional flows. It is also designed to get the room temperatures up within 60 minutes from memory - there is a set of parameters hidden somewhere and you can alter these. 
 

If you’re using ASHP as a heat source then you really want to be using E7 and overnight - slab on at 3:30am to absorb low grade heat for 3 hours etc.  That needs a lower flow temp and closer to the final room / slab temp you’re looking for so ideally it’s nearer the 35c flow (most ASHP have 35c as optimum for CoP) blended with the return water. 
 

Ignore that entirely !! That’s the flow the ASHP needs, not the floor. The floor flow is set by the manifold circulation pump, not the ASHP pump and it’s a bad idea to just connect the ASHP to the manifold and hope it runs ok as the zones closing will play havoc with the flow. 
 

I’d use a small buffer  - 60-100litre - and let this do the balancing to the ASHP. The heat pump then uses the tank stat on the buffer to fire rather than the call for heat from the UFH controller as it is less likely to short cycle or find flow restricted. 

 

Very good advice. I'm still at the pre-building controls submission stage. Trying to get the Foundation design finalised. Hopefully insulated raft with UFH.

 

Based on various threads here, I have a very simplistic UFH design at present.

 

ASHP does only UFH. Sunamps for DHW.

1 Manifold ground floor with 6 loops all 95m, 200mm spacing

1 Manifold first floor with 4 loops all 95m, 200mm spacing

2 zones: ground floor, first floor

In Loopcad water temp 30 degrees, target room temp 23 degrees. (30 default in LoopCad, 23 hottest that should be need, actuals will probably be different.)

 

I used JH's Heating Requirements spreadsheet and the heating requirements from Loopcad, the two figures were quite close to each other: "Total daily heat loss power for minimum OAT (W) 4147"

 

The flow rate and Delta T were the main areas, I don't really understand.

 

In Loopcad, if I set the Delta T to enforced fixed at 5 degrees, I get a flow rate of 1.42l/m on all circuits, giving a total of 15l/m flow rate. If I let the software calculate the Delta T, ground floor DT is 2.8 degrees with a flow rate of 2.4l/m. On the first floor the DT is 4.1 degrees and the flow rate of 1.6l/m, total flow rate of 18l/m. But I don't know what I'm trying to target, is higher flow better, is lower Delta T better. Reading lots on the web did not really make this any clearer.

 

I was expecting the ASHP pump to drive the ground floor circuit at a constant temp set on the ASHP. For the first floor circuit have a mixing valve, pump and thermistor, with a slightly lower temp. This config is in the manual. 

 

I was not planning on having a buffer tank. I was happy for the ASHP to be on 24hrs, just hitting the target water temp.

 

Obviously this is all hypothetical, and I enjoyed reading the various threads here and watching the LoopCad tutorials. At some point an actual Plumber will have to be engaged to make all this happen. These are just my research ideas.

 

 

 

 

 

 

Edited June 7, 2020 by Nick Laslett

[Nickfromwales]

On 06/06/2020 at 15:23, Nick Laslett said:

 

I wondered about this on the spec sheet of the ASHP I was interested in.

 

This was the Panasonic WH-MDC07H3E5

 

Spec sheet: Water Flow rate 17 l/min (17 litre per minute)

 

Is this the ideal target, or maximum or minimum. The text of the Spec sheet has no further details.

It’s the flow rate that the ASHP needs to see on the primary side eg the flow to and from the unit itself. To ensure that is always met on low energy builds I design in a low loss header for most instances, basically just a tiny buffer tank, to achieve hydraulic separation between the ASHP and the load. That allows the pump of the ASHP ( primary side ) and the UFH pump(s) on the secondary side to never ‘meet’ hydraulically, therefore the primary side is nigh on free-flowing. You then just set the primary pump to the desired flow rate, eg the rate that satisfies the minimum unit flow rate requirement, and then it doesn’t get affected by changes with downstream loops opening / closing etc.

Plumbers usually follow the MI’s, so if they’re at all worried you’ll probably end up with them wanting to fit a buffer tank. 

[Nick Laslett]

4 hours ago, Nickfromwales said:

It’s the flow rate that the ASHP needs to see on the primary side eg the flow to and from the unit itself. To ensure that is always met on low energy builds I design in a low loss header for most instances, basically just a tiny buffer tank, to achieve hydraulic separation between the ASHP and the load. That allows the pump of the ASHP ( primary side ) and the UFH pump(s) on the secondary side to never ‘meet’ hydraulically, therefore the primary side is nigh on free-flowing. You then just set the primary pump to the desired flow rate, eg the rate that satisfies the minimum unit flow rate requirement, and then it doesn’t get affected by changes with downstream loops opening / closing etc.

Plumbers usually follow the MI’s, so if they’re at all worried you’ll probably end up with them wanting to fit a buffer tank. 

 This is great info, thanks. I was only just reading @NSS thread Panasonic Air Rads Be Warned where his set-up had a low loss header, and there was good discussion about it's function. He was trying to get a higher temp to the air rad. According to the Panasonic Installation manual, with the simple 2-zone config I was looking at, it says that Zone 2 must be the same or cooler than Zone 1. 

 

I assume that this simple set-up will work in reverse when I need cooling in the summer?

 

*Edit Just came across this interesting article on UFH regarding water temp and buffer tanks. https://heatpumps.co.uk/2014/03/06/getting-the-best-from-underfloor-heating/

Edited June 8, 2020 by Nick Laslett

[Nickfromwales]

1 hour ago, Nick Laslett said:

I assume that this simple set-up will work in reverse when I need cooling in the summer?

Yes, as due to the very low volume the LLH can remain inline during cooling. They come with factory insulated jackets so make sure you go for that option when buying or you may end up with a condensation bomb.   

[Russell griffiths]

New layout from wunda. 

Any improvements needed here. 

@Nickfromwales @PeterW @ProDave

 

NR1620 Russell Griffiths PIPE LAYOUT REV B - FINAL COPY - A1 (46 High Street).pdf

 

 

[ProDave]

I would still delete loop 1-2 in the hall and just space out the rest of the pipes that are passing through the hall on their way to other places.

[Nickfromwales]

2 hours ago, ProDave said:

I would still delete loop 1-2 in the hall and just space out the rest of the pipes that are passing through the hall on their way to other places.

They won’t sign off on that design as you’d then be dissipating heat into the hallway that’s destined for satellite rooms. That would see reduced flow temps arriving at those rooms. 
Best to remember that this is not a full ‘passive’ insulated raft, it’s a relatively thin screed over insulated block and beam so will be heavily reliant on the design specifications not being lost. 
I’ve suggested to @Russell griffiths that he insulates the flow pipes where the runs are congested and just uses the return ( residual ) heat to warm the hallway. The hallway loop should not be removed though, as it’s cost is negligible, and to not have it wouldn’t make any sense ( imho ) even if it doesn’t get used ( for provision of auxiliary heat in the hallway ) for 10 months of the year its better to have it than not to for the sake of £100. 

[Nickfromwales]

Also, if a bedroom is mothballed, you’d get no heat from it’s origin so the hallway would then get nowt from that loop. 

Edited June 11, 2020 by Nickfromwales

[Nickfromwales]

2 hours ago, Russell griffiths said:

New layout from wunda. 

Any improvements needed here. 

@Nickfromwales @PeterW @ProDave

 

NR1620 Russell Griffiths PIPE LAYOUT REV B - FINAL COPY - A1 (46 High Street).pdf 1.65 MB · 7 downloads

 

 

You’re good to go Bruce. ??

[connick159]

Can someone please explain why bed 2 has 2 circuits but bed 3 only has a single circuit? I can't work it out?

 

Also, if this was installing UFH in an extension plus the existing property, but in the existing house the UFH was going on top of slab floor already there but in the extension it would be onto slab, with insulation and then screed, would you still recommend a single 12 port manifold or to split them onto to 2 diff manifolds. One for new extension and other for existing house?

 

Cheers.

[Russell griffiths]

8 hours ago, connick159 said:

Can someone please explain why bed 2 has 2 circuits but bed 3 only has a single circuit? I can't work it out?

 

Also, if this was installing UFH in an extension plus the existing property, but in the existing house the UFH was going on top of slab floor already there but in the extension it would be onto slab, with insulation and then screed, would you still recommend a single 12 port manifold or to split them onto to 2 diff manifolds. One for new extension and other for existing house?

 

Cheers.

It’s to try and keep the loop lengths under 100m if possible, if you look at the chart at the bottom of the drawing it shows loop length.