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If you need a hot water store for the bath I would also use it for the shower.

You can flush and disinfect the pipe yourself. Flush it through with clean water first, to remove any crud, then fill it with diluted, un-thickened, unscented, domestic bleach for half an hour or so, then flush it through again with clean water until there's no residual smell of chlorine. Instead of beach you can use calcium hypochlorite granules, sold as "pool shock", for disinfecting swimming pools. Does the same thing, just mix it with water to get a bleach solution. I've had to do this a couple of times with our borehole, whenever I've pulled the pump out and replaced it

Local instant water heaters start to make sense when the point of use is a long way from the main house source of hot water. If it gets to the point you have to run off twice as much cold water, just to get the hot to the tap, as you actually use once it gets there, then I would say that is a candidate for a local small heater. One of the design inputs to the house layout was to keep bathrooms etc reasonably close so we don't have that problem and water reaches all the taps with little waste. Contrary to popular practice, I piped all my hot water from tank to tap in 15mm to minimise the dead volume in all runs. For a small wash hand basin I would probably go down to 10mm even for the hot feed to that to keep the volume down.

We've discussed the possible health risks here before, but the bottom line is that in a closed system, supplied by mains water, there is zero risk of any bugs growing in the hot water system, as far as the inlet to any taps, mixers etc. Bugs have to have a way to get in in order to start multiplying, and that means the water supply either being compromised somewhere, or being open to the air, say from a break tank, cold water tank etc. There is a small risk from standing water left in the pipes feeding a shower head, as that water is exposed to air and sitting at room temperature, so it's a good idea to not let a shower sit unused for long periods of time. The more frequently a shower is used, the less chance there is of bugs growing in that water column. Even then, the risk is low, but exacerbated by the water being sprayed into the air in the first second or so that the shower is running, so increasing the risk that any bugs will be breathed in. If someone has a compromised immune system, or is suffering from lung disease, then the risk from using a shower for the first time in a week or so could be minimised by placing the shower head in a container of water when first turning it on, perhaps. In reality I suspect the risk is very low, and not something that's likely to ever be a problem for a shower that's in regular use.

I have had confirmation this morning that the tap unit has no NRV internal on it. However I had an epiphany this morning, the bath tap unit is in the wall and just has copper blanking tails currently ie no cartridges or taps. In my mind this essentially is allowing the cold and hot water to flow wherever it wishes. I need to install the cartridges on the bath tap and see what testing reveals.

Could we perhaps at least let a fellow self builder settle into the community for a while before chastising them for misuse of the 'eco' word? ?. Welcome @Chedbuild, and hang onto that enthusiasm ?

In case it is not obvious, I will make it so. This stuff is concentrated, you dilute it massively before use. 5L will last you a very long time and cover a large area.

Yes, any glyphosate with "360" in the description is generally the strongest concentrate that's easily available. I've been using Gallup 360 for years, as it's generally the cheapest way to buy concentrated glyphosate. £30 sounds about right to me, I'm pretty sure that's about what I paid for the last lot I bought. It does contain a surfactant, but it can be slightly improved when used on waxy-leaved weeds by adding a squirt of detergent, to help it wet the surfaces of the leaves a bit better.

We have ensuite pocket doors (and similar to bathrooms and dressing room). All are 44mm solid doors using Eclisse ironmongry and a haefle pocket door system. I'm guessing a glass door would need to be custom made - how would you fit it to the runners above? The pocket door systems are fairly fixed width so you'll need brushes either side to hide the gaps.

Depends on who is behind it.

Don't they screw a dosing pipe into this to inject chlorine? IIRC, the aim is to get at least 50ppm of chlorine solution into the pipe and leave it for an hour, or 200ppm and leave it for 30 minutes (I've done the latter). I think the regs say to use sodium hypochlorite, but I've always used calcium hypochlorite, as it has double the free chlorine content.

I have paid a personal pilgrimage to this holiest of shrines to self-build centralized manifoldness. It is a wondrous sight though at the time I could only comment on the colour of the floor tiles.

Depends on whether you want to take advantage of an off-peak tariff, like Economy 7, really. I have our UFH set to charge the slab up overnight, at the cheap rate, and unless it's really cold we don't need to boost it during the day. Doesn't make a massive difference, in the overall scheme of things, as the heating energy use is so low that the cost saving is probably less than the cost of an evening out at the pub for dinner. I sometimes think I've spent far too much time and effort thinking about optimising stuff to the last few %, when in reality I'm not sure if it really matters if our annual heating bill is £100 or £200. It's pretty modest in the overall scheme of things, certainly when compared to the ~£1150/year we spent on heating and hot water at the old house. You could just not bother with programmable thermostats, run the system all the time, and have the temperature set by a few room stats. Given the pretty slow thermal response of your house (I'm guessing it'll be similar to ours) it should just stay at pretty much the same temperature all the time with such a system, barring a bit of solar gain warming things up a bit.

Only if you’re using E7 and want to make sure you take your E7 usage to the wire as they use GMT time clocks so you need to be careful with the shoulder hours.

In the near constant temperature world of UFH and a highly insulated building, does the GMT/BST thing matter?

My point is that you're looking at the wrong "they". This is a very important point, and it's critical that you (or whoever) do the best job you can of thinking ahead at the design stage and sorting out which decisions need to be made early and which can - or sometimes even should - be left until later. Again though, my point is merely that a lot of what you're concerned about in this document are not things that architects will generally be familiar with. Maybe you can pay your architect for an hour to go through this document with you and tell you which things he/she can help you with, and those for which you should be looking to others.

@AnonymousBosch, worth noting that the manifolds pictured in @ProDave's setup are for the UFH, not hot and cold water distribution. The ones in the photo of @PeterStarck's installation are for hot and cold water distribution, not UFH.

Looks like the forum software has “helpfully” inserted the wrong hover text on AAV here. I'm pretty sure Jeremy means Automatic Air Vent, not Air Admittance Valve. A Air Vents let air out, A Admittance Valves let it in.

Best to run both from manifolds, IMHO, as some of the imbalance problems affecting flow come from cold water outlets, like toilet flushing. The other advantage of having all the hot and cold feeds coming from a manifold is that you can fit ball valves to the manifold outlets, so allowing individual pipes to be isolated at source. This can be really handy when first commissioning things, as you can turn supplies on one at a time, check for leaks, function, etc, then move on to the next. It also means that any feed can be isolated in the event of a leak, leaving the rest of the plumbing still working. Being able to do all this from one, fairly easy to access, location, seems useful, apart from the advantages it gives in terms of faster hot water to taps, lack of interaction between outlets, etc.

Ok Jeremy corbyn

Exactly. Why would you design in a space to house a ceiling mounted projector when technology has moved on. Short throw 4k projector is where you need to be looking. Won't require any additional work other than the normal ethernet cables,hdmi , speaker etc that you plan to use anyway. Will just sit on a unit and look like an ordinary set top box.

Yes. But mainly because I want the solar PV to be free to top it up, rather than have some time clock deciding when to top it up which probably does not coincide with surplus solar PV being available. And I doubt it's software has the built in logic to say "oh it heated to 65 degrees yesterday by some unknown means so I don't need to do it manually"

Yes, but the advantages are significant, as you also lose any interaction between things like the wash basin and shower, or toilet and shower, if you run separate pipes (a toilet is fine on 10mm too). Running pipes from a common manifold fed with a fat pipe gets rid of pretty much all the interactions you can get with flow rates varying as taps are turned on or off, toilets are flushed, etc. If running plastic pipe, then the cost difference for all these extra pipes is pretty tiny. If running copper, then 10mm pipe can be PITA to run, especially if trying to feed it through posijoints, as it will snag on every web.

10mm is absolutely fine for a wash basin supply. The French have been using small bore pipes for decades with no ill effects, IIRC, I think their "standard" pipe is about 12mm OD, so a fair bit smaller than our 15mm. Using 10mm plastic pipe is even better, as the pipe has a slightly smaller bore and a much lower heat capacity than copper, so hot water will reach the tap a lot more quickly (under 5 seconds for a 10m pipe run, which is pretty good). The wasted hot water is also a lot less, as in a 10m pipe run of 10mm plastic pipe there will only be about 0.385 litres of hot water, which if supplied at 45°C (which is what I have our mixer valve set to) will only "waste" about 0.0113 kWh, which is so trivial as to not even be worth considering.

That is what I do with mine. One of the user parameters is "water leaving temperature" which has two settings, one for DHW and one for space heating. I still have the blending valve in circuit, set to it's lowest setting. That protects the UFH when the HP switches from DHW mode to heating mode, from a slug of 55 degree water still in the pipes that would otherwise go straight into the UFH loops if the blending valve was not there.

I guess you could do that. I run our ASHP at 40°C, as, by experiment, I've found that it never seems to run a defrost cycle when run at that temperature, but i could lower it and do away with the thermostatic valve. The buffer would have less effect, but I'm not sure that would be that significant, as at the moment it can run the heating for around 3 hours at a fairly typical 400 W of heating demand, which is much longer than is really needed just to stop the ASHP short cycling.

yep very common practice, and also wrong and probably illegal (well it should be if it isn't). I would expect a builder to negotiate better prices than I can; that's fine but getting a product price of £1 and then telling me its costing £1.50 is fraud. tell me its a quid and then charge more for labour. and if that makes the labour look expensive that's another matter but this practice of lying about the cost of materials is shocking.

There's no doubt that instant heating with peak rate electricity is far more expensive that heating water any other way, so the real question comes down to whether the convenience of having near-instant hot water from a tap is worth the additional cost. A basin tap typically flows at about 5 to 6 litres per minute (any higher than this tends to result in a lot of splashing). Using 5 litres/minute as a general figure, then if that tap is fed with 10m of 10mm OD plastic pipe (so about 7mm bore) then it will take about 4.7 seconds for hot water to arrive at the tap. So, any instant water heater has to be able to heat water, and deliver it to the tap, faster than that

My last experience of a "limited" shower was when in the static caravan. That was heated with a 10KW instant propane heater and produced a poor shower flow. You had to compromise and have it a bit too cold just to get barely enough water.

TBH, even the higher losses from a UVC aren't going to change the overall balance. A UVC might lose around twice as much heat as a Sunamp, but that's still nowhere near enough to swing the balance in favour of using instant water heaters. The only reason for considering instant water heaters is really convenience, in that they may provide hot water at taps a little bit quicker. In practice I doubt this is that noticeable, as if small bore (10mm or so) pipes are used to feed basin taps, with a radial plumbing configuration from a distribution manifold, then the few seconds delay before hot water flows is probably much the same for either instant heating or tank-fed hot water.

Wow, that's impressive. Way more than his fee saved with a single phone call!

I have no deliberate anti bacterial cycle. (mostly) in the summer surplus solar PV heats the HW tank via the immersion heater and on a good day it approaches 70 degrees before the immersion heater thermostat opens. But that is not going to happen in the winter. We discussed this at the time, and the conclusion was our mains water originates from a cold mountain loch where the chance of any bacteria surviving in the first place is low. It then goes through a treatment plant that included a microfilter. So we can be pretty sure there is no bacteria in the water when it arrives. The hot water tank is unvented, so there is no route for contamination to enter. So the consensus on the forum at the time is any bacterial risk from the stored hot water in incredably small.

Just an update, Andrew (the VAT man) has just emailed me to say he has got a “VAT legal expert” to look at my claim (at no cost to me) and he thinks I may get another £1000 refunded (minus 22% fee). Watch this space.

We have an immersion for anti legionella protection but after reading here that there has not been a single case of domestic problems with this I have not bothered to wire it up. I believe the problem comes from stagnant water in shower heads that are not used fir a period of time. Edit to add,- As i had not heard of pseudomanas I had to look it up and found this, Pseudomonas is a germ found in the environment. It can occur in moist areas such as sinks or baths. It rarely causes illness outside a hospital or healthcare setting.

If you are using standard lintels for openings and don't have cantilever floors or no wall returns you should not need one.

Why do you need a structural engineer? With regard the foundations the BCO should be able to give an indication of what he wants, a couple of test holes should prove it!

A major improvement then!

So potentially 10mm out from one stud to the next. ? (1° ~= 1:60).

Just splashed out on two of these beauties for £15 with change! https://www.ebay.co.uk/itm/3D-Laser-Level-Self-Leveling-Point-Line-Cross-Horizontal-Vertical-With-Tripod-UK-/143368654797 (I'll just have them constantly on doing this next gate pillar). ?

Sorry I am struggling to understand that. It is an on / off valve (probably proportional) As such it can allow water to flow or not flow or flow slowly. I cannot see how it can do any blending, it can just adjust the flow rate to get the desired difference between flow and return. But that might be at a high or low temperature depending on the feed temperature.

Just a thought - could you not use something like a fibre optic light pipe to extend the status LED ..? As usual, cheaper in the US than here ...

Sadly the Sunamp gives no indication of its state of charge, so there's no way of knowing if it's at, say, 60% at all. It's a significant issue, in my view, as not knowing what the thing is doing is one of the single most frustrating aspects of having one. Mine lives with the cover of the controller off, so at least I can see the status LEDs on the control board (I'm not recommending that anyone do this, BTW). Flow rate is not a worry at all with just a single Sunamp, now that they have increased the pipe size to 22mm and increased the performance of the internal heat exchanger (relative to the original Sunamp PV). They are capable of delivering pretty good flow rates, at least as high as the largest combi boilers that are available, and on a par with an unvented hot water cylinder, so it may well make more sense to just fit a single, larger, unit.

Meat. Eat a huge hunk of ham. See what doesnt happen. Oh, and by the way, eat just a small amount of corn on the cob at the same time. (Used as a transit marker).

It is yes, but pseudomonas can tolerate chlorine to a certain extent, heat or ozone is the only thing that is 100% guaranteed to kill it. It lives in drains and damp soil, so you can imagine what it has to put up with, it coats itself in something called a biofilm which prevents all the things which normally kill bacteria from working. As an aside, it also has the ability to evolve, and has become one of the most resistant bugs to antibiotics. Have a look at this, as pseudomonas isn't the only bacteria with a biofilm: https://www.ncbi.nlm.nih.gov/pubmed/27146505 Careful design and consideration is all thats needed. Having spent the last 18 months reading intensly about this particular bug, i'm probably more aware than others at just how bad it can be, so wanting to put all that knowledge to some use.