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Thank you @Nestor - that's great. Really appreciate your and @Nickfromwalesinput, as I've been going around in circles! That's interesting - I'd aimed for about 10-15mm difference and add a threshold strip, but perhaps I should aim for less. If so, would 10mm insulated tile backer board work, screwed to battens? It would lower the height and at least add a little more insulation, although the screws would be thermal bridges. Or gypdeck 18, which is t&g. I'm not sure which electric ufh - yet another thing I need to research, so I'm open to recommendations!

Gee this thread has gone mad, gone from what looks like an over calculation of 9kW, to people suggesting 3 phase monster heat pumps.

Flow is king with heat pumps. Excluding the mixer for now. Your flow limit comes from the flow meters on the UFH manifold. The flow added together of each loop is basically the max flow rate you can get through the system. Open each loop another 0.5 l/min, that will add 5l/min flow. To increase flow turn the black part of the flow meter on top manifold anti clockwise. If flow doesn't increase look at the mixer pump speed settings and increase the speed. Next - a later job. Your mixer isn't needed, it's just causing a bottle necks and unnecessary mixing. Plus it doesn't allow you to run weather compensation very well. You also need to run a higher flow temperature to compensate for the mixer valve. So get a worse cop. Two pump running cost you more money. I would be installing a single 5 or 6m head pump that does UFH and your DHW heating. Delete the mixer and pump.

3-phase is common in even small houses and flats in Germany so they would need to. Delta connection, no neutral. I had a Belling Lee cooker made in the '70s that for the export market had an elegant arrangement of busbars so the loads could be split onto the three different phases if required. Sadly expired 3 years ago, best cooker I ever had. Could do little things like use the top oven on the timer which I could not find in a replacement. All modern cookers seem to have fans to keep the controls cool which annoyingly run on for ages, maddening if you have a kitchen/diner. /reminiscence

I. agree, you agree. It was really a comment on @ETC contributions. Addressing overbearing and cramped should get this passed.

I had a similar issue with my LG heat pump originally. The biggest issue was mine just had a flow switch and I did not know how much short of the required flow rate I was. So to solve that I bough an in line flow meter. It turned out I was not much sort of the required flow rate. In my case the LG had a pump inside it (does your Samsung?) so I added another pump as well in my plant room meaning both pumps were in series and that gave me enough extra flow to get over the line.

@Rosslyn just wondered how you got on with your foundation design? We too are getting close to that stage; highest plasticity clay and a hedge the full length of the house with tree species has me a tad worried!!

Finally got a plumber to connect up my Samsung ashp. This is to take the place of a heat battery. The system is as simple as possible with no zoning. A second pump has been added (a Wilo Pico), in addition to the original Grundfos supplied with the u/f kit. I would have liked to have had the blending valve removed but this was too much for the plumber! The maximum flow rate per the Pico read out is 0.9m3 which I am assuming equals 15 lpm. The manual indicates that I need 17lpm so not fast enough and I get a low flow error code each time I try to run it. Research on the net seems to give me two options. The first is to install a new pump with a greater speed capacity and the second is to somehow run the two pumps in parallel which seems to increase the flow speed. A final option is to move the second pump from its current position of being on the return to the heat pump to being on the flow side. If it is not already clear I am not a plumber but should be capable of simple pump replacement etc. Any thoughts welcome.

We did something similar in our last house. If you want to keep the hand pump and make it electric. You basically need to take out the piston affair, from the hand pump so the pump doesn't pump. The pump then becomes an empty pipe. In the well, drop a submersible pump on a rope into the well water, pump size will depend on how many metres it needs to lift the water and flow rate needed. The outlet of the electric pump needs to be installed into the the pipe that leads to the hand pump. The original pipe that came from the well, to the hand pump should only have a single feed from the electric pump now, so will need to cut the original pipe or hose. So you need access to well and pipe that leads to hand pump. If have to make access not a small job. Run a hose.

Should hope so, they need to give you some for £5k for their smallest heat pump. Plus you have to pay extra for cooling! Mitsubishi is the most comprehensive, I've seen and I've seen a lot.

I agree, but if you thought 19 objections last time was a lot, this will probably stir up more and open up other possible grounds for refusal (not in keeping with the area)

Might find this simple Spreadsheet handy for EV sizing calcs etc, or just for interest Expansion MASTER Vessel Calculation extract rev0.xlsx

Don't rush to get running, especially while your still working on house, it will drag in all the dust etc - you don't want that.

You don't need volume in the cylinder circuit. Think it's because the water to water heat transfer is so good, compared to water to air on a typical heating system. But you calculate volume in the heating circuit to get away from any likelihood of short cycling, basic calculation, is you need at min modulation, min modulation kW multiplied by 20, assuming no tvrs or manifold actuators (any circuits with either are excluded from the volume in the calculation). That should be your minimum system volume, but more is better. The volume number in the manual is the volume needed to support defrost. If you need to add circuit volume stick in a volumiser, generally in the CH side only on the return piping.

"That valleys gonna give me problems down the line"?

I was thinking about this on Thursday when I realised that our system volume is only enough when the Underfloor Heating (UFH) is in the loop when its just running through the domestic hot Water (DHW) tank the volume is a lot less. However I also feel that as far as the DHW tank is concerned the heat transfer is roughly reversable, I guess entropy and a few other factors will have a part to play, so the hot water in the tank will give its heat up to the circulating HP circuit and so all will be well. I dimly recall working out that we might need ~0.8kWh for a defrost, if all that comes from the Tank - because the other volume in the system during a DHW cycle is only around 31l (Including the tank coil) we would see a drop in water temperature of a few degrees which may or may not be a worry depending. (To use that side the heat pump will be in DHW mode so a set point is engaged somewhere and defrosts could result in it getting in loop trying to reach set point while being knocked back by defrost cycles). When the slab is in the loop and based on the same assumptions as for the tank defrost the temperature drop is a fraction of a degree across the slab, the systems volume then is around 60l, the slab is 60T of concrete and there is no close in setpoint to worry about.

OK thanks, I'll carry on with the insulation and get the MVHR running ASAP. I was wondering if others have experienced the same. I've already got a dehumidfier running upstairs 24/7 and the loft has enough ventilation to dry out any moisture going up there.

Can see this now more clearly on my Laptop, the relief valve that is lifting is the expansion relief valve, while not a safety issue this should not be rated the same (6bar) as the TPRV which is stated on the cylinder data as being 6.0bar (& 95C), just ensure ASAP that the TPRV rating IS stamped 6.0bar as labelled on the cylinder. (Your Caleffi combination valve does appear to be plumbed correctly, as you described) Normally a UVC with a 6bar TPRV would/should have a 4.5bar expansion relief valve and if the precharge/filling pressures are 2.8bar/3.0bar then the final pressure when UVC is heated to 60C will be 4.0bar or 4.24bar with precharge/filling pressures of 3.0/3.2bar. You can see from the screenshot that the expansion relief valve setting is 4.5bar.

I've recently been working with someone who has been using Protek. I have to be very careful about what I say here as I use my own name. One miss step from me here and I'll get sued and will probably lose any case. It's not just Protek it's also the NHBC, both will take my trousers down if I slander and rightly so. That said the rep from Protek told me the MD was a hands on guy and he would phone me. He did not and that was not good form! I'm not taking favour as many other warranty providers make caveats and have "fine print", insurance is a business, a very competetive one. I kind of know a bit about this as from time to time I advise Clients when they are claiming against warranty providers. To do so I have to understand just what was the policy covers and what it does not. To put this another way.. I pitch up on BH and folk are chipping in to say that SE's are crap, Architects are crap, builders are crap .. and we are all over charging you and not taking on any, or, reducing our liability. The warranty providers are fighting back to keep their premiums competetive. One way they are doing this is to pass the risk on to other designers, so thier risk is less and they can reduce the premium. As above I need to be really careful about what I say. My own view is that the warranty providers have recognised that self builders often just want to get cover so the can get lending it's almost akin to selling car insurance. Providers caveat this as the market is competetive. It's a race to the bottom. As a self buider you need to ask yourself. Do I want cover so the bank will lend to me or do I want cover that actually secures my assett and investment. So I'm going to quote Ruskin here: mull this over. There is hardly anything in the world that someone cannot make a little worse and sell a little cheaper, and the people who consider price alone are that person’s lawful prey. It’s unwise to pay too much, but it’s worse to pay too little. When you pay too much, you lose a little money — that is all. When you pay too little, you sometimes lose everything, because the thing you bought was incapable of doing the thing it was bought to do. The common law of business balance prohibits paying a little and getting a lot — it can’t be done. If you deal with the lowest bidder, it is well to add something for the risk you run, and if you do that you will have enough to pay for something better.”

Hi all. From time to time I commission a CCTV drain survey to get build over permission. It comes with a report and a video, attached. Once the works are complete we do another survey which shows we have not damaged the water board assets when executing the works. As an SE I'm responsible for designing the foundations so they don't damage the drains in the long term. Now, there are more explicit videos... but as BH is a family site... The video goes blank at times, even the camera has moral fibre. We can see quite a lot of ground water ingress at one of the joints, the water board still passed this as the structural integrity of the pipe was ok, I think. If they had admitted their joints were failing that could have opened them up to claims.. it's a weird world. Build over permissions can be serious if you come to later sell your house. Drain Survey 1 (Subclip #1).mp4

I got timed out on adding a bit more so here it is which should be apended to my last post: To add a bit! Lots of younger designers, Architects included, have great ideas, some have good old common sense. But they lack the strength and depth of experience to comminicate that to you and then be able to present the business case to you and then explain how they are going to present a planning application, they forget who is paying thier wages... you! One fundamental that you need to instill in young designers is that.. you can be as talented as you like, but if non of your stuff can be affordably built then you are on a sticky wicket! But on the other hand if you sell yourself too cheep then that also leads to a hiding to nothing. I'm ah.. a little older, my problem is keeping ahead of the game as all these young folk are taking no prisoners! The rules change regularly, I have to keep up.. I can't claim grandfathers rights, it's an open competition. @SilverShadow Have confidence in your own ability. From experience I can tell you that many desingers will embrace an informed Client, builders also!. Yes, they may ask you for a bit more fee money but that is a fair days work for fair days pay. Builders like certainty.. if you have Client that keeps changing thier mind the cost often goes up, then they have the hassle of try to get paid for the extras. If the Architect /Designer has not done a detailed job then it all becomes tricky. Builders know this, I used to be one so sometimes added on a "fanny" factor if I though the Client could be a dick head. If I got the job and they turned out to be great I would often do some extras for free, then I stood a better chance of getting recommendation as.. everyone loves a builder that comes in under budget! Now if you think ahead to the build. By going through this process you'll possibly identify other potential savings. A good trades man costs say £ 250.00 - £300.00 a day. If you hit it off with your designer they could easily wash their face fee wise. Think strategically.

I've got a couple of projects on my books at the moment, one is a new build the other is a refurb / extension. The planners on the new build have opened the gambit by saying, they think the garden will be over shadowed, the planning officer said they had just been promoted, but here were initial comments essencially pre the formal application ( it's complicated at the council admin went of piste) it was a can kicking excercise. One the other project I have a privacy issue as I'm relocating a conservatory. Below is the kind of extra work I've put into my planning submission. Don't forget I had to survey the site so I could produce a drawing that will become part of the legal planning submission, that takes time and a lot of thought as the levels are not horizontal. One part of the art here is to recognise the obvious things the planners will clock, but not be too technical and indavertantly introduce things they have not thought of which can then invite them to use you as a "free training " excercise, part of their CPD. What I do in these cases is to lead and inform my Clients, each time I say, "I think this might work" I back it up by evidence. I provide info such as the attached so the Client can read and see for themselves the aguements I might want to put forward. I've attached two typical documents I sent to my Clients, one is Scottish based, don't knock it! It's easy to get your head round. This "easy document is based on the UK guidance, BRE 209 which is quite technical so to get your head round that you need to read the easy document first. Now all this does not come for free. There is mention of say getting an Architect for a few grand. But many desingers have special skill sets you need to be prepared to pay for and recognise that this strength and depth of design skill takes many years to develop. Best thing you can do is to read through what I've attached, use AI to help you on terminology, but always check? it's not always right! It's incorrect as it seems no one has spent the time or effort to put together and evidenced based design. At the end of the day you will probably kick youselves if you later find out you chucked in the towel before you even got started. You designers should know enough to say, this has got no chance, if so then why are you taking the risk. OR they should say we think this can be justified, there is latent risk and, refer to the documents I've attached. Now don't forget the Planners can't just run around being loose cannons. Some planning decisions go to appeal, this costs the councils lots of money in hours spent. If they keep losing appeals then their bosses hold their feet to the fire. In summary if you inform yourself a bit more then you'll find a design that embraces your enthusiasm and you'll likely make great progress. All the best and keep your heads up! Daylight and Sunlight guidance 17-06-21.pdf BRE 209 Site Layout Planning for Daylight and Sunlight BRE 2022.pdf

The only supplier I have found with good info on modulation is Viessmann where they show a shaded 'output area' for min and max output at each OAT temperature, possibly even different charts for different flow temps.

Havn't read all the posts but a 22L EV should be OK for a 248L UV cylinder. Assuming a (now) cold mains temp of 10C and a final HW temp of 60C and a full cylinder reheat each time, then...... precharge/filling pressures of 3.0/3.448bar = final pressure of 4.63bar. No problem. precharge/filling pressures of 3.0/4.25bar = final pressure of 6.0bar. Assumes PRV is passing and rises to 4.25bar precharge/filling pressures of 1.31/3.448bar = final pressure of 6.0bar. Assumes EV air end pressure (precharge) has fallen to 1.31bar. (50psi = 3.448bar) If the TPRV is set to 6.0bar, then the expansion relief valve should be set lower and should have lifted first, what is this set to??, it should be stamped on the end of it (red). Is the pipe from the EV connected in at the "bottom" of this expansion relief valve??. Also what is the Caleffi PRV model, it may not be drop tight. The Caleffi 535 is drop tight The Caleffi 533 is not drop tight

In a fit of hopefulness about finishing my build (or insanity, I'm not sure...) I bought a couple of Acrimo motorised curtain tracks in a Black Friday sale so I could evaluate them. For the price I am quite impressed - the whole thing cost not much more than a similar length manual pull cord rail. The curtain rails themselves are designed nicely and implemented well. The battery built in to the motor and supplied small solar panel and is a nice feature to avoid running power (I already have power there, so that was a waste of wire...). The instructions however are less good unless you understand Spanish because the translation to English has some comedy moments. That said, the product doesn't really need too many instructions because the basic set up is fairly intuituve. Of course motorised curtains are silly unless they are automatically controlled somehow. The instructions claim the motors have two RS485 connections via a RJ45 connector, but then don't explain much more about these. The RJ45 connector also has some logical connections to trigger opening and closing. I could use a micro controller connected to Ethernet (Pi Pico or similar since these are cheap enough) to operate the curtains according to the home automation system's commands but it would be fewer components and therefore better if I could work out how the RS485 bus works. I am waiting for a couple of USB RS485 interfaces to arrive in the post, but in the mean time does anyone have experience of these motors?