Problem: The boiler is in the kitchen at the front of the house and the outdoor unit of the ASHP would need to go in the back garden. How to connect them with Uponor Ecoflex Thermo Twin HP, a large diameter insulated pipe for hydraulic, electrical and electronic connections?
The house was built in 1995 and has a concrete beam & block ground floor. My ideal solution would be to run the pipe under the house and up through a core-drilled hole in the kitchen floor. There is a kitchen unit close to the boiler and if it surfaced under that it would be almost invisible except for possibly some boxing at the back of a cupboard.
The excellent technical support at Uponor suggest that it is technically feasible but cannot identify a contractor that could do the work. They are only aware of contractors that undertake commercial/industrial projects.
The core drilling is feasible (although I don't know the Building Regulations aspects). I know that builders have put basements and wine cellars under existing houses. Others have sprayed thermal insulation under suspended floors. If a drain under my house broke I imaging there would be somebody that could fix it.
I really want to avoid the disruption of moving out furniture, ripping up carpets and floorboards and running large bore, insulated pipes up the outside and through the fabric of the house. If I can't avoid that aggravation I might just scrap the whole project!
With heat pumps set to become a common replacement for gas boilers, insulated pipe connections under the ground floors of houses without basements doesn't seem such an outrageous solution.
Has anyone achieved something similar?]]>
I presume there is an air space under the beam and block? One thing to consider might be the minimum bend radius of the pipe, which might be quite large.
If you're looking for suitable contractors then giving your location may help.]]>
I would not think it was difficult to core drill such a block with a core drill in an SDS drill (not on hammer action), going through a beam would be a no no you would not do it with that set up anyway.
I have drilled through a cavity block wall i.e. 2 blocks with a 150 mm core drill without problem in order to get MVHR ducting to the outside.
The concrete drill contractors you mention are specialist who drill through concrete walls and floors often with rebar in and use specialised machines and jigs to hold the drill and guide it automatically, you no not need that if you have a standard beam and block floor.
How much space have you under the floor? DJH makes a valid point about the bend radius I guess the more room under the floor the easier it will be.]]>
Guess you already looked at putting the indoor unit nearer to the outdoor, ideally back to back on the same wall? It can tie in anywhere there's a main heating flow& return, or not a big job to extend/enlarge the F&R to somewhere convenient. The other thing was the indoor unit needed multi-kW power supply so maybe a new cable run from the CU, where would be most convenient for this, if needed?]]>
I would take out a whole block, easier, cheaper and quicker than drilling. Then fill back in with sheet insulation or foam strong screed on top
Are there any sleeper walls? It is ok to take out half a block underground between or parallel to beams but fill round pipe to rat-proof it]]>
+1
A fairly easy DIY job. But first beg borrow or steal a rebar locator or pipe locator that works, (I have found that the cheap diy units are unreliable), and locate your beams 'cos you really don't want to hit one of those.
As said above - this assumes you have space under the floor.]]>
Normally each run has a single hot water pipe through the middle, surrounded by a couple of inches of insulation. However the product mentioned in the OP has two pipes (F &R) and two electric conduits, through the same bundle, so doesn't have space left for much insulation. If using this, you would probably want to wrap a few inches (at least) of insulation around the outside. Beware that heat will leak across from the F to the R pipe, IE shortcut without going into the house.
This primary pipework is the hottest point of the CH system running effectively through the outdoors, so any lack of insulation will be costly!
I don't know about block floors. What dia hole can you core through each block before it falls apart? Needs big enough hole to feed the 6" stiff pipe through with wiggle room.
Alternative might be to split the bundle under the floor and run individual CH pipes and electrical conduits up through the floor, each through their own 2" hole, if these can be made without the block cracking between them.]]>
Certainly if the pipe can be split into smaller component parts then installation will be much easier. Perhaps the hardest part would be getting the first pull through in.]]>
- height of floor void versus bend radius. Bend radius might be 8xdiameter. Could use single pipe rather than dual.
- height of floor void and access to it for installer
- what is the floor build-up (blocks, sometimes there's a screed over the blocks to level the floor, then insulation, then floor slab/screed???).
- if you run underground externally, you'll likely want to pass the pipes over the foundation level from outside, through the blockwork underbuild. What depth is the top of the foundation? The solum may be above ground level, so would need to penetrate that unless the pipes rise above ground level externally.
- allowable length of pipe run, and can the run be shortened. Shorter run might mean lesser diameter, and so lesser bend radius (if that's an issue)
- confirm the pipe sizes, are they single or dualed, therefore what's the outer duct diameter. Could be 90mm if single, but could be 175/200 if dualed.
I would try to answer the above points, before considering the bit through the floor, as that's the relatively easy bit. If you take out a big enough area, then the pipes can rise at an angle through the floor, incorporating some of the bend radius above floor (should that be an issue).
Maybe a quick site plan sketch might help our understanding, and poss lead to ideas to help reduce the issues?]]>
Some more details:
Space under the floor. Unknown (I think the minimum is 150mm). There are Periscope® Underfloor Vents front and rear. The incoming water supply comes up through what looks like a 150mm brown plastic drain pipe through the floor next to the stop valve. Might be possible to insert an industrial endoscope for a look.
Viessmann branded quattro connection line (2x40x3.7-1x32x?.?-1x25x?.?/160): diameter 160mm; bend radius 600mn; core hole ?.
Uponor Ecoflex Thermo Twin HP (2x40x3,7-2x32x3,5/175): diameter 175mm; bend radius 700mm; core hole 250mm.
Uponor Ecoflex Thermo Twin HP (2x32x2,9-2x32x3,5/140): diameter 140mm; bend radius 500mm; core hole 200mm.
Each has two hydraulic pipes and two conduits (power, data). 40x3.7, for example, is the outside diameter (40mm) and wall thickness (3.7mm).
I would hope that the smaller Uponor connection would be sufficient, it's roughly equivalent to 28mm copper. The other two are roughly equivalent to 35mm copper.
It would be a straight run roughly 4.5m outside, 8m under, not allowing for the bends at each end.
The floor in the kitchen is cushioned vinyl; moisture resistant chipboard; extruded polystyrene (XPS) 25mm; concrete screed. There's a vapour barrier in there, too. Don't know what is below the screed. Architect told me it was beam & block construction around 12 years ago.
Location is Cambridge, UK.
Core drills in this size range typically require a special rig that can be bolted to the floor (or wall). I've seen one in use. Impressive what a diamond drill can do!
This won't be a DIY project. I'm neither young enough nor fit enough! If I want my house wrecked I will leave it to professionals with good insurance.]]>
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Perhaps the solution is to use a ready-made 200mm hole? Uponor's "Ecoflex Solutions Technical Information" lists a "Fibre cement pipe PWP" (Order Code: 1007370; liner pipe diameter DN 200; for jacket pipe diameter 140mm; length 400mm). Don't know how it would be set into the floor. One for a structural engineer?
An illustration labelled "Slip Brick Detail" in https://www.milbank.co.uk/app/uploads/2022/08/T150-2.pdf shows a pipe passing vertically through the join between two blocks.]]>
I would do the following, were it my project for a client:
- investigate the underfloor depth. There may be a hatch somewhere, but you won't know where that is, or you'd already have had a look under. I'd remove the kitchen cabinet (drop legs, unscrew from adjacent cabinets, slide cabinet out) where the pipes are planned to rise. Cut out a piece of the chipbrd. Then likewise the screed. At some point the blocks will appear. Then you'll know where the conc beams are. Drill a hole to allow the depth to be confirmed (or cut out a block and have a good look). I'd expect there to be insulation in the floor buildup, as 25mm 12 years ago would never have passed build regs. If it's between blocks and screed, then you can easily cut access to the blocks, and break one out. Set a new one back in, if the project is a no-go.
- investigate the foundation depth by hand digging externally. Then correlate that with the internal void depth check (as above). That will give you info on the external pipe run
You'll need to pay a local builder for a days work to do the above. No big deal, and at least you'll start the design process with firm knowledge. This is the boring, dirty, hard work, unlike using imagination for designing which is fun, but the design will be nonsense without it.
Usually, plastic pipe is measured to the external (so 32mm ext, less 3mm plus 3mm gives internal 26mm, for example).]]>
The house was built in 1995. The architect was involved in the low energy renovation 12 years ago. The building standards were lower when it was built. The insulation was originally expanded polystyrene. Replaced with extruded polystyrene (XPS) because of load requirements of the washing machine and 350l thermal store (and water damage under a vinyl floor - minor drip from washing machine connection; plumber saved time by running microbore pipe diagonally across vapour barrier under chipboard creating small lake; fungal heaven; insurance job!). Microbore on ground floor for radiators was replace by 15mm copper during low energy renovation.
All good suggestions for further investigation. However, I am reluctant to have anything seriously invasive undertaken until I am happy that there is an approved way of passing the Ecoflex through the floor and providing support for it.
Typical insulated pipe building entries are horizontal. Viessmann's fixing suggestion is "The pipe is fixed directly in the brickwork with expanding mortar or concrete (no other accessories required)". Uponor have wall seals with metal faces that compress a rubber ring. Neither seem likely to work well vertically through blocks of low mechanical strength.
Thanks for the comments.]]>
Confirm that the blocks are 440mm x 215mm x 100mm. If so, obtain a https://www.travisperkins.co.uk/padstones/supreme-concrete-high-strength-concrete-padstone-440mm-x-215mm-x-102mm/p/508623" >Supreme Concrete High Strength Concrete Padstone 440mm x 215mm x 102mm or similar. Have it core-drilled with 2 x 125mm holes and 2 x holes for conduits. A https://brandportal.uponor.com/m/05c7b17a7482fd7f/original/IM-Ecoflex-wall-seal-PWP-EN-1022113.pdf" >Ecoflex wall seal PWP could be used to hold a pipe. A single wall seal, 65mm long, should be enough to hold a pipe. The padstone is unlikely to break like a regular beam.
Run the quattro pipe to the house wall. Connect to 2 x https://www.uponor.com/en-gb/s/uponor-ecoflex-thermo-mini-32x2-9-68-1018133" >"Uponor Ecoflex Thermo Mini 32x2,9/68" and 2 x conduits.
If a horizontal holes were required there is wall sleeve NPW (non-pressure waterproof) with heat-shrinkable sleeve that only requires a 90mm hole.
Uponor Ecoflex Thermo Mini (32x2,9/68) diameter 68mm; bend radius 250mm; core hole 125mm.
I'm not a builder but it looks like this would make the task easier. Any thoughts?]]>
Why not get some candidates round to look?
From your description it's not obvious that you think there is a workable space under the floor (likely need a couple of feet height).
If not, rather than get bogged down with choosing piping products, take a step back. The installer will have faced this before. Kick some ideas around with them about where the indoor unit should go, or indeed whether you need a HP with an indoor unit at all. (The indoor units are just a box with plumbing bits in like zone valves, expansion tanks, pumps etc, which you might already have with your thermal store). Installing all the insulated multicore pipes linked above is going to cost a couple of £k which may be avoidable, or spent a better way?
Also let the HP installer buy the bits as then they can go within the zero-VAT scheme.]]>
Why not get some candidates round to look?
From your description it's not obvious that you think there is a workable space under the floor (likely need a couple of feet height).
I am also interested in the possibility that the task could be achieved without someone crawling under the house. Unlikely with a 140mm pipe and 500mm bend radius! However, with 2 x 68mm pipes with a 250mm bend radius it might might be possible. If there is the minimum 150mm height (or more) it might be possible to excavate enough for 250mm bends from above.
Posted By: WillInAberdeenIf not, rather than get bogged down with choosing piping products, take a step back. The installer will have faced this before. Kick some ideas around with them about where the indoor unit should go, or indeed whether you need a HP with an indoor unit at all. (The indoor units are just a box with plumbing bits in like zone valves, expansion tanks, pumps etc, which you might already have with your thermal store). Installing all the insulated multicore pipes linked above is going to cost a couple of £k which may be avoidable, or spent a better way?
My motivation is to avoid as much internal disruption as possible. Past experience with furniture moving; carpet lifting;
chipboard floor lifting and so on in a bigger renovation project has made me strongly averse to that approach. If the work can be confined to a small corner of the kitchen I would be much happier. If keeping me happy costs more then I will judge if the price is worth paying.
The installer will have faced this before. Will they? My installer hasn't heard of an ASHP install with the pipes run under and up through a beam & block floor. I have asked here and elsewhere but nobody has told me of an example where this was done. Uponor technical support didn't know of one either.
As a customer, I don't know who might be suitable for this work. There are parts of it that could involve architecture; building; heat pump installation; HVAC; groundwork; plumbing and structural engineering. Maybe even a ferret and a long piece of string? Any solution would also have to satisfy building regulations.
It hardly seems like a Grand Designs project to get a couple of pipes a relatively short distance.
Posted By: WillInAberdeenAlso let the HP installer buy the bits as then they can go within the zero-VAT scheme.
Good point.
Thanks for the comments.]]>
I suspect the first thing to do is make any kind of hole at all, either in the floor or through a wall, and push an endoscope camera with a light in to see what's there. The camera needs to have distant focus, as well as short range.]]>
"My installer hasn't heard of an ASHP install"
Sounds like they might not be very experienced then, but I can tell you of a plumber who could do it; my father in law has his ASHP installed in just about the furtherst possible point it could be away from the hot water tank (about 30m) and the tank is, in turn, as far away as it could be (up to 12m) from most the points of use. It takes 3 pumps to get the DHW feed sorted, and when he wants hot water to his kitchen tap he turns it on full bore and then goes back to cooking for half a minute.
What's crazy is, the water passes the tap on the way to the tank and comes back half the distance. This all because he "had to use that alcove in the wall to install the outdoor unit so it didn't impact the driveway width" and "had to put the tank in that airing cupboard on the second floor in one corner of the house" and "had to have the bathrooms and kitchen in the other corners of the house".
"It hardly seems like a Grand Designs project to get a couple of pipes a relatively short distance."
Anything can become a grand designs project the more the person with the money says "it absolutely has to be ..., and it must not be ..., oh and I also want ..."
And from what I read I've a slight concern that might be the path being taken here..]]>
I have had similar thoughts. Running a string then a draw rope should be relatively easy (assuming no obstructions).
However, insulated pipes are usually rolled into position to avoid damaging the outside casing. Would it be acceptable to pull/push a pipe into position? Are there ways to protect it using a slippery channel or mat? Would a pulley wheel be needed to provide a straight pull?
Posted By: djhI suspect the first thing to do is make any kind of hole at all, either in the floor or through a wall, and push an endoscope camera with a light in to see what's there. The camera needs to have distant focus, as well as short range.
Having been involved in looking for tube leaks in a 1923 Babcock & Wilcox water tube boiler using a camera on a stick I know how tricky it can be to interpret the images! Maybe it would be easier looking under a house?
I think there are questions to answer before making holes. I need to know if there are permitted ways to pass pipes or other services through an existing beam and block floor that comply with Building Regulations.
There are still questions that probably need answers from a beam and block expert and someone with experience working with these pipes.
Thanks for the comments. It feels like I am moving towards a solution.]]>
There should be no problem coming up through a block because the blocks are only infill between the beams and removing a number of them won't affect the integrity of the floor.
Given that the elements are not structural I don't see that building regs would be involved or have an interest.
A lot of the blocks here are hollow with 2 holes (the blocks have a central divide) that are 18cm wide and 12cm deep. these holes line up as the blocks are laid on the beams so it would be possible to pass a pipe down the centre of a row of blocks once access to the ends is made - if you have that type of block.]]>
Posted By: john.connettI need to know if there are permitted ways to pass pipes or other services through an existing beam and block floor that comply with Building Regulations.
There should be no problem coming up through a block because the blocks are only infill between the beams and removing a number of them won't affect the integrity of the floor.
Given that the elements are not structural I don't see that building regs would be involved or have an interest.
A lot of the blocks here are hollow with 2 holes (the blocks have a central divide) that are 18cm wide and 12cm deep. these holes line up as the blocks are laid on the beams so it would be possible to pass a pipe down the centre of a row of blocks once access to the ends is made - if you have that type of block.
Totally agree except think the UK blocks used are solid variety. Just consider the blocks as being floor boards over joists. A hole in the floor board is not considered structural but in the joist yes]]>
If you're nervous about the floor, then make a hole through the wall first. That should be easy to patch up later if it's not in a useful place. Going through the floor the important thing is not to damage the beams - they're pre-stressed concrete so won't take damage well. So figure out where they are first.]]>
Existing tank, 350l with solar thermal, is in a ground floor under-stairs cupboard. Doubt if the indoor unit would fit in there as well. Even if it did, it would require a contortionist to plumb and maintain it. Similar problems with the pipe run. Either boxing through the lounge over the beam and block floor or up the outside wall, through the first floor and back down. Don't think I am becoming blinkered but other options seem less appealing.]]>
Many other models of monobloc ASHP do not use an 'indoor unit' to collect these bits together, so you may be able to keep your existing pump/valve etc unaltered, if that helps make the job simpler or less disruptive? Just run the ASHP pipes as you described and then straight into any convenient pipe connected to the store.
(Edited for clarity, and to add:)
Maybe you could get/buy an offcut of the preinsulated pipe? Once you handle it, the practicalities of dragging and bending it will become cleaer to think through, and the adequacy of the insulation it comes with.]]>
| Device | Location | Notes |
|---|---|---|
| Circulation pump | Gas boiler | |
| Flow/return plumbing to TS | Gas boiler | |
| Diverter valve | N/A | System boiler. Mains pressure DHW via TS. |
| Immersion heater | TS | |
| Safety valve | Gas boiler | Drain plumbing in place |
| System controller | Gas boiler | Including mains power connection |
| Bus terminals | Gas boiler | For heating circuit with mixer module, solar thermal module |
| Outdoor temp sensor terminals | Gas boiler |
The gas boiler is conveniently close to the Consumer Unit for additional power connections for the ASHP outdoor unit (and 3-stage instantaneous water heat, if required).
I'm not sure I understand your simpler or less disruptive solution.
(Apologies for the strange table formatting).]]>
"The Vitocal 200-a is a monobloc ASHP with an indoor and outdoor unit.."
Er.. Monobloc means everything is inside one box, so monobloc systems don't have two units; everything sits in the outdoor box, as opposed to split systems where it is typically refrigerant that passes between two units.. Vitocal appear to be using monobloc to describe that warm water is emitted from the outdoor unit rather than warm refrigerant
"Doubt if the indoor unit would fit in there as well."
"The indoor unit should sit close to the tank" wasn't the message I was intending to convey]]>
Perhaps additional cabling is easier to run than insulated pipes?
(I write this having just put a decent conduit under the new bathroom floor in readiness for a cable from CU to boiler room, to facilitate Heat Pump power supply in future)]]>
If an indoor unit is required then it has to go somewhere. There is a suitable space in the kitchen occupied by the gas boiler that is plumbed in to the rest of the system and is conveniently close to the Consumer Unit for additional electrical connections.
Kitchen is at the front of the ground floor, lounge is at the back. Cylinder under the stairs in the middle. There is a bedroom at the back on the first floor. The indoor unit could go in the lounge or bedroom, perhaps hidden by an extra cupboard, reducing the space in an already modest-sized house. Either location would need additional plumbing and electrical connections.
Posted By: Dominic CooneyPerhaps additional cabling is easier to run than insulated pipes?
Both are required, unless I stick with a gas (or electric?) boiler.]]>