ProDave

No, the unvented tank. With a vented system it's not the tank location that matters but the header tank. You could improve it a bit by putting the header tank higher in the loft. But if fitting a new unvented tank and it won't fit the airing cupboard, put it in the loft.

Saturdays weather here

In this situation, most just put them up in the loft.

Is that grid tied, or purely off grid just for the pool? Can I see some pictures of the tracker mechanism? I'll bet it was not cheap.

Yes an automatic bypass is essential. In my conversations with LG I think I found it needs to sense sufficient flow within 10 seconds otherwise it will trip. Even a standard 2 port motorised valve will barely open in 10 seconds, so a bypass is essential. In the case of the LG heat pump it is an actual flow switch which consists of a weighted flap that triggers a hall effect sensor when it moves to the "open" position.

That would persuade me to have 3 phase if it was available.....

It does vary widely. We only have single phase here from a single phase 11KV overhead line that is at least half a mile from the nearest 3 phase network, so you could imagine the upgrade costs if we tried to get 3 phase. But if it is available and you think you might be close to the limit, it is worth getting it. Where we are the network is close to bursting, we were only offered a 12KVA supply which as it happens is plenty. And when I registered my G83 solar PV (now G98) they initially miss read it and thought it was 4KW not 3.68 and were about to quote me for the required network upgrade. So we have no hope of more than 3.68Kw without paying for something to be upgraded. I believe this is all because a number of houses share a 100KVA pole mounted transformer and in the last 15 years about 4 new houses have been added to that same transformer and they are just looking for someone to charge to upgrade it to something bigger.

LG let themselves down badly with information in the installation manual, but their telephone technical help line solved the problem. CH14 comes up when the inbuilt flow switch senses the water flow is too low. Sadly they don't say in the manual what the water flow rate should be, or how to measure it. I bought and fitted a flow meter and fitted it into the flow pipe from the heat pump, and this showed that the inbuilt pump was not delivering enough water flow. So I solved it by fitting a second pump inside the house in the flow pipe and that gave me enough flow and the problem has not come back. I wouldn't worry with a flow meter, just buy and fit a second pump and that should solve it. I just wired my second pump in parallel with the inbuilt pump. But that does mean an extra cable needs to be run from the heat pump to inside. An alternative solution, as yours only tripps occasionally so is almost enough flow, might just be to replace the inbuilt pump with one that gives a higher flow rate. It is a small Wilo pump they use so just replacing it for a larger type might be all you need to do, but you would first need to look up the quoted flow rate of the pump you have and seek something a little but more powerful. If you are wanting just to get someone in, then I would suggest a plumber, ask him to look and see what pump is fitted already, then specify and supply a more powerful pump to replace it with. Keep the Wilo pump as a spare, they are nice pumps as they tend to be very quiet, I fitted those to both my under floor heating manifolds because the original ones were too noisy. But in this case it does not mater if the new pump is a little more noisy as it is outside.

A lot of 3 phase meters measure KVA That's thousand Volts.Amps rather than Watts. The difference is, if the load is not in phase (i.e power factor less than 1) you get charged for the amps consumed but they translate to less actual power used. I can't see it is going to be a big concern for the average domestic property, though it would be interesting to find out what the power factor of say a heat pump is. 3 phase will let you have three 16A PV systems without prior notification. The downside is the house loads may not be on the same phase as the PV to use that power so you have to think carefully how to spread your loads for best effect. What is the reason that is driving you towards 3 phase?

Yes, £50 for a new connection. And there is a good chance you will get that back. It took Open Reach so long to actually make our connection, and find a working spare pair of cables all the way back to the exchange that I complained, and got the connection fee refunded by way of compensation for the delay.

Hi and welcome to the forum. That looks a pretty good and eficcient house layout to me, not much I would change.

I wish the jet stream would bugger off somewhere else. I was supposed to be sailing today

My neighbours house is tiled with flat tiles that have a line down the middle, they are meant to look a bit like slates and for that to work would need to be offset by 1/4 of a tile from the row above. But they are all laid with no offset at all.

And I expect the problem with trying to do that would be it would result in a water flow rate that was too low for the ASHP. Our LG one in particular demands quite a high water flow rate otherwise it will shut down with an error code. Typically when our ASHP is heating the hot water tank, it runs with a return temperature about 6 or 7 degrees lower than the flow temperature. This idea would need a return temperature to the ASHP of abour 30 degrees lower than the flow temperature (from the Willis) That is just not going to happen.

A company I did some work for took that approach. I would be interesting to see what others on here have done. @Crofter what did your PP say?

When defining it as a "caravan" keep planning and building control separate. Planning only need to know the size shape and appearance of the building. If it happens to be of such a size that it could be built as a "caravan" there is no need to even mention that fact on the planning permission. Once you have planning, you can decide to construct the building conforming to the legal defenition of a caravan and thus avoid a lot of building control issues, but that is a separate matter to planning.

This is the Highland Council document on the subject. It makes it clear this is a building for human habitation and only the drainage needs a building warrant, https://www.highland.gov.uk/downloads/file/1346/bst_018_caravans_and_mobile_homes

I would have thought there was a pretty good chance of getting PP for self catering in Orkney. It could then still be built as a "caravan" once you have PP. Look at @Crofter blog, That is exactly what he has done, built under the definition of a "caravan" with only a building warrant needed for the drainage connection

Regardless of PP, have you thought about building it as a "portable building" so in law it is treated as a "caravan" you can build up to 100 square metres like that without a building warrant as long as you stick to the legal definition of a "caravan" (which does not require it to be on wheels)

Welcome. Does your user name suggest you are on the northern isles?

Nothing wrong with engineered wood over UFH. Our last house had Maple, and this one has Oak. And if anything, I find the heat transfer to the rooms downstairs with UFH pipes in pug mix and wooden floors is better than in the bathrooms that use spreader plates and tiles. UFH is never a "quick heat" system, it works best at a low level but on for a lot of the time. Just make SURE you have a LOT of insulation under the floor.

I did say that was not "how to do it" It WAS tied.

I joined ebuild in about 2013 or 2014 as we were starting on our second self build. I have a history of forums shutting down on me. Our first self build started in 2004 and then there was a buildstore forum that I used, but that shut down and disappeared overnight part way through our build with no warning that it was going to or no explanation of why. Thankfully the way this forum is managed there is no single point of "control" and being managed by a number of people should ensure it continues.

And once it has done that, then there is definitely no pee in it.

Don't take this as a "how to" rather a "what I did" Here you see my longer ladder right up to the top platform . Re extra bracing. I used some spare diagonal braces to add extra bracing to the corners with the bottoms staked to the ground. Note also the "bracing tower" projecting to the right in the middle of this span.