Two questions relating to UFH manifolds

[Bancroft]

1. Can manifolds be fitted in the loft space of a single storey building, instead of on the ground floor?

 

Our loft is going to be within the warm envelope of the building.  I'm already looking at housing the MVHR and DHW in the loft area and I'm wondering whether mounting the UFH manifold. system there too is a good idea or not?

 

To my mind, the more 'plant stuff' I can shift out of the normal living space, the better.  As some houses have UFH on the first floor, I imagine pressure differentials shouldn't be an issue (but that's just a guess).

 

There's also a strong possibility that the pipes from the external ASHP into the manifold will be entering the house structure at ceiling level anyway so they're going to have to go from ceiling height to ground level at some point, so why can't the manifolds be at the high end of that drop?

 

If they are mounted in the loft, what are the potential down-sides of such an arrangement?

 

2. Can multiple sets of manifolds be run off the same ASHP?

 

We're building a 211 sq m single storey building so there's lots of floor space to cover.  One initial design I had done resulted in 18 different pipe circuits - although they did include laying dedicated circuits in the hallways, utility room and pantry which we could probably do without.

 

The maximum number of circuits on a single manifold system seems to be 12 and the likelihood is we will hit this and perhaps exceed it.  So, how easy is it to have two separate manifold sets in the system?

 

Having two sets might also help to reduce the number of pipe circuits/length of runs by having the manifold sets strategically placed apart, rather than trying to run everything back to a single point in a building that's 25m long.

[JohnMo]

7 minutes ago, Bancroft said:

We're building a 211 sq m single storey building so there's lots of floor space to cover.  One initial design I had done resulted in 18 different pipe circuits - although they did include laying dedicated circuits in the hallways, utility room and pantry which we could probably do without.

We are a similar size to you with 7 circuits. So there us plenty of room to reduce the number of loops. I wouldn't have dedicated loops on hall and certainly no loops in a pantry.

 

We have one loop per bedroom 3x, 2x in lounge, one loop ensuite, another loop does main bathroom, then does hall area near front door and then kitchen diner. I would simplify to a single manifold - post your design and get it reviewed?

 

Manifold can go anywhere, but you have a lot of pipes (36 at the moment) to bring down the walls, if upstairs, the pipes are likely to need insulation as the area will get very warm, also you will need a deep service void - I would find space central downstairs (airing cupboard) then run flow and return to manifold.

[Bancroft]

Thanks for that @JohnMo.  Plan attached below as recommended.

 

I think the design given to us was a lazy one and doesn't really look at the issue intelligently - hence a hefty dose of scepticism on my part.  150mm centres in an ICF house with thick slab foundations seems a little excessive...

 

I agree that pantry and hallway need to be deleted, and going to 200mm centres - or even 300mm - will massively reduce the pipework.  I just need to get the re-assurance that the wider centres will still achieve the aim with regards to heat output required.

 

If we are able to reduce to one manifold set then the lobby between bedrooms 2 and 3 would seem a logical place (centrally placed and cupboard space available) but I still like the idea of getting stuff like this out of the way, even if it does mean a bit of extra insulation.

[JohnMo]

I would 

Delete all dedicated hall loops, spread all pipes transitioning through halls out across floor.

 

Come down to one manifold only.

 

Do 200mm centres generally, but keep bathrooms at 150mm or below. Maybe even 250mm in bedrooms, but just do a single loop in each bedroom.

 

If you locate the manifold in utility, you wouldn't need a loop in there either, just spread pipes across the floor.

 

This is our floor, loose 300mm centres. Kitchen is generally 0.5 Deg cooler than lounge, bedrooms are a degree to 1.5 cooler than rest of house with doors closed. Open doors and the rooms even out over a hour or so.

 

[Bancroft]

Your example looks a lot more sparse than ours!

 

Couple of questions:

 

• I notice you haven't put any pipe under the gangway between kitchen units and island - does that not create a cold spot for people working in the kitchen?
• Also, in the bedrooms, you've not put pipe under the bed locations - does than not limit you for switching the room around or altering the layout?

I've been playing around and looking at loop sizes for 200mm spacing and managed to get down to 14 loops but I did this using a spreadsheet - how easy is loopcad to use and what other data do you need apart from room sizes/locations?

 

[JohnMo]

15 minutes ago, Bancroft said:

I notice you haven't put any pipe under the gangway between kitchen units and island - does that not create a cold spot for people working in the kitchen?

There is a single pipe, between wall units and island not on drawing but on photo, floor temp is low - you don't notice it unless really cold outside, talking -9 for a day or 2. Then you only notice it, but only with feet at the kickboards. We have 100mm concrete screed, so the temperature spread is pretty wide away from the pipes.

 

16 minutes ago, Bancroft said:

• Also, in the bedrooms, you've not put pipe under the bed locations - does than not limit you for switching the room around or altering the layout?

 

Very unlikely the rooms will get moved about as whole is there for the views, which disappear with the bed on a different wall or dining are at the other side of the room.

 

18 minutes ago, Bancroft said:

how easy is loopcad to use

I found it ok. You basically build the house in the software, so you need U values, window sizes etc. Its good for balancing floor outputs, I got mine to within a few Watts for each room, so system balance is good out the box.  I found later wife had very different ideas to floor covering for bedrooms than me, as a result bedroom output is a little low than planned, but works ok. Nice wool carpet insulation.