Dan F

The values I found and used when I used this calcutor were: Copper: 0.001 - 0.002 10-3 m Hep2o: 0.007 10-3 m

Did you rule out the manifold approach instead of a loop? As for your questions on pressure drop, the best way to understand how what you have proposed will work in practice, IMO, is to model it using your specific scenario including pipe lengths, diameters and type. How long your 22mm loop is will have an impact, as will if its copper or plastic. This tool is fairly easy to use, just ensure you use internal bore diameter, reduce pipe smoothness if using plastic and account for fittings and elevation. Add your bath at 25l/min and a tap further along loop at 8l/min and see what pressure loss is. Specification sheets for grohe taps will tell you how many bar you need at outlet for a given flow rate. https://www.engineeringtoolbox.com/water-supply-system-design-d_2157.html (The tool assumes that the flow rate specified can be achieved from supply)

I've been taking a look at this too: Some people use black rather than browm, but (light) blue is a must, as is yellow/green for earth. This one is interesting: - Loxone use orange/white. - The US (and the old version of the IEC standard) use red/black - New IEC standard is brown/grey - EN 60204-1 recommends dark blue + white (with blue). Most people seem to use a mix of red/black (tri-rated) and orange/white (twisted pair) in practice from what I've seen.

@Hilldes Did you decide on a colour code?

Got it. I'm not a plumber or UVC expert, I did design all the pipe runs based on flow rates and lengths for our house though (in order to avoid a recirculation loop) which is why I was picking up on these elements. 10mm hep2o has a ID of 6.7mm, so what does this mean: - volume of pipe is 458ml, giving you hot water in 2.8 seconds if you run at 10l/min, which is good. - the design flow rate of 10l/min gives you a velocity of 4.7m/s. Plastic pipes are good at bit more than copper (copper is max 2.5m/s), but 4.7m/s is very high even for plastic. (The hep2o spefification charts go up to 3m/s) - the pressure loss over 13m at 10l/min (with no fittings) is 8.5bar, so the 4.7m/s isn't going to happen anyway! That said, you should probably be able to get 4-5l/s, but why wouldn't you go up one size or add a 10mm hot return? (a 10mm hot return on a single outlet is nowhere near as bad as running a larger hot return around the whole house) With 15mm hep2o the hot water wait time would be 7.8s at 10l/min and you could run at 10l/min with velocity of 1.7m/3 and only 0.5bar pressure drop. This seems like a better option unless you want to find something in 12mm and try to hit the sweet spot.

OK, thought I saw you said "I've opted to use 10mm for the kitchen tap as the run is 13m" 6hrs ago.

@joth I realised the other day that the "mySolarEdge" app gives you limited options, but using the "SetApp" app gives you a lot more options. You need to use the "SetApp" route to enable Modbus TCP which allows Loxone to get data from inverter (without the need for a Modbus extension).

Whas the kitchen then; 16mm MLP, 10mm copper or 10mm hep2o?

It's hard to comment without more information. What flow rates are you designing for? Are you planning to use copper, or plastic off of the manifolds? How long are the 15mm runs to the showers? Using a manifold and micro-bore pipes to avoid a hot recirculation loop is a good idea but, in my opinion, to be sure you get it right you really need to look at each run and the veolcity and pressure loss, based on design flow rates, be be sure you are using the correct pipes.

I have temp sensors in each room (part of Loxone light switch) as well as 1-wire temperature probes in the slab in each room. Advantage of the having temperature probes in the slab is they give more direct feedback and can help ensure the floor slab isn't heated too much or is too cold (to avoid condensation). Do you know how you will control UDF and/or if you'll use any home automation of any kind? Depending on this you may want a different type of temperature sensor.

The miniserver and extensions now all come with Wago 243 connectors for 24v too, so I'm going to need to use twisted pair for these unless I buy expensive single-core tri-rated stuff. Does anyone know exactly what the regulations say about when tri-rated cable is/isn't needed?

The standed cables are easier to work with in a cabinet as they are more flexible. What I didn't/don't know is: - How well stranded cables (with or without ferrules) work with the push-in connectors used on the new minisever for 24v/tree/link. - If tri-rated is just required for 230v, 230+24v but not tree/link/DI, or if it's best to use it for everything.

Even if they are within the same cabinet?

Are these tri-rated though? There seems to be a good selection here: https://www.tlc-direct.co.uk/tcl/search?query=Tri-rated&Submit=Search

I haven't ordered them, that's the thing. I just asked electician to supply some. Will let you know once they arrive though.. I'd seen these previsouly, but at 200m per colour, seems a bit excessive: https://www.fscables.com/products/tree-cable-jumper-wire-designed-for-loxone-system.html

I beleive UK regulations mean you need to use "tri-rated" cable. I'm also about to buils my panels, I have agreed that our electrician will supply the Weidmüller terminal blocks and tri-rated cable though, which I'm waiting to arrive. I'm hoping they will supply solid vs. standard cable. Various others on the forum have also built cabinets and may have suppliers they can recommend for this. @Rob99 @joth @jack

Download phone app, then go to "inverter status" or "inverter communication" and it should ask you to scan a QR code. The next step is flicking a switch on inverter so that it broadcasts its own WiFi network which the app connects to.

Same here. It is relevant though because the average person bathes 20% of the time and fills the bath halfway before getting in, and that's what the regs are based on. I don't think BCO's will go round and check this, they they do want the paperwork though. What did your paperwork declare?

I'm all for not wasting water. it's the method used to calculate water efficiency that is arbitrary because it make assumptions about how often you bath and how much you fill the bath, while almost completely ignoring water use for irrigation, car washing, swimming pools and hot tubs etc.

One option is to do as you suggest and use Salus auto-balancing actuators on each loop. You shouldn't need to expliclty turn off the loops next to the window, but rather the actuators will automatically reduce the flow in these loops based on the return temperature. Wunda sell these actuators. The other way of thinking about it though, is that the layout they proposed may do a better job of distributing heat across the whole areas as all loops will continue to circulate water.

Thats another option I didn't think about! Do away with the bath and build a swimming pool instead. (uses lot more water.. but passes regs ? )

Question was tongue in cheek. Just musing over the imaginative, and potentially valid, workarounds for water efficency calcs.

The whole water efficiency thing so abritary though, that it seems rather silly to get a small bath to comply! Yeah, this is another option, but building regs doesn't specify what a "Spa Hot Tub" is. Aside from it having bubbles, it might need to be left full ?

@Rob99 What did you use in the end?

We've gone a ordered one of those fancy stone-resin freestanding baths from Lusso. The only problem is that it has a 350L capacity and because the smart people that came up with the water efficiency calculation in Part G seem think we'll use it regularly and fill it up, and are going to fail Part badly. We could delay the installation of the bath until after BC approval or maybe install the bath but not connect it to the water supply yet, but I think I've come up with a much simpler more creative solution: Assuming this bath has a volume of 35L, the installation of one of these, will bring our average bath volume down from 350L to 193L. If we install two of these, then the average bath volume reduces to 140L. Either way, we'd be under the 125L/day and everyone should be happy, or am I missing something? Has anyone got any experience with baby bath installation? Alternatively. does anyone have any tips on how on how we might be able to convert a bath into a "Spa Hot Tub" (these are are simply exluded)! Would one of these stickers do the trick do you think?