Nickfromwales

Nope, all good. For under the tray or for the remainder of the bathroom flooring? If the latter, green P5, for the former as per @Temp’s reply.

Isn’t that only if it runs through the gen / export meter? I’ve a friend who has added panels and battery storage to a FiT’s install, but that element is 100% unaffected by the addition of batteries as the charge is captured and sent into a 3rd party BMS and goes around the existing and into its own MCB, thus only ‘preventing’ import. Yup. Spot on. You can change failed equipment but needs to be like for like, eg you can’t have a failed 250w module replaced with a 365w etc. You can add a BMS and put the batteries onto the DC side, and put 48kWh without issue. The BMS can be dialled down to zero export, and you can G100 and declare, with the DNO often either then asking for equipment details and usually a witness visit to observe the zero export in operation.

Stiebel Eltron are the Bentley of the HP world, and are Uber-fussy with the installation criteria, ask me how I know!! Not a bad thing, but they are very focussed on correct and immaculate execution wrt to the implementation of their products. A simple and acceptable ‘adaptation’ would meet their criteria; eg the employment of a much larger UVC for one, plus some manipulation of the flow temps of the HRC vs the stored temps of DHW ( and flow temps to it ). The HRC can then be made “invisible” to the HP so as to not upset SE. All in a days work lol. Not exactly If the HRC has no demand and managed losses then there would be no heat energy lost, ergo nothing to then keep triggering as demand aka call for heat, at least no more than acceptable latent losses attributed to the system and its components. A HP is there to provide heat energy, end of. It must do its job, simples. How the install is designed and executed will dictate the efficiencies of the system as a whole. I think it is very narrow-minded of SE to state the above, but that’s if it is designed for a domestic installation. If it is not, and you apply it to an adverse scenario, then expect the fleas to come with the dog.

A man after my own heart. Pulsing the hot return in this scenario would be an epic fail, and using a pipe stat to decide when to pulse would still not yield an acceptable result afaic. Just insulate this run(s) very well and switch on and off via a dusk to dawn sensor for ‘daytime’ use, and then fall back to occupancy switching for nighttime use ( where someone moving at night would trigger a recirc event ). Make sure the hot return pipe is the same size as the delivery pipe, or evacuation times for the delivery ( aka flow ) leg will be hindered by the return pipe size.

Erm, just buy a different pan? There are plenty to choose from!!

I always drill through at a much later stage for the various projects I undertake, PH dwellings and airtight ones alike. It is of absolutely zero detriment to do so if done carefully, and sympathetically. Conduits get fitted through correctly sized holes, executed and sealed according to the dwelling type, plus running slightly downhill to the outside to stave off ingress of moisture ( in the event of my thorough sealing-up ever failing ). Getting from the ground up to the cavity would be an issue, with conduits needing to be surface mounted / exposed or set in place prior to the external 'skirting' arrangements being fitted. The location of your ducts would then command where the electrical device could go, eg where the cable could then rise in said safety zone. Install all of these later, and spend the interim deciding what exactly to put where, exactly.

The product I refer to there is that "no more leaks shower seal" item. Yup. So all of that gets done as one wet application. You'd butter the Wedi with CT1 immediately before dropping the tray in, then apply an excessive amount around the 3 sides, and then you'd tool that into place as per that thread to create the up-stand. My second favourite currency lol.

If you are a growing household then you may eventually struggle with a combi, but there's me ( showers ), the missus ( 1800x800 bath to fill ), and 4 kids ( mix of 2 showers + 1-2 baths ) at ours and I have a combi and am happy with a few cons for the pro of not having to have a cylinder. We're happy to observe a "nowt else running whilst someone's in the shower" policy, and that works just fine for us tbh. I will change that this year, hopefully, by adding a type of thermal store to the cold feed that supplies the combi, eg so it receives a stable input of pre-heated 'cold' water, which will remove my one major niggle with the combi. That is the fluctuation in hot water delivery ( associated with any type of instantaneous water heater, not just a combi ) when the hot or cold does get used elsewhere during a shower. That will be further offset by the installation of a cold mains accumulator ( just a 100L one to cover the <30L of draw-off from the mains from other use eg WC#2 being flushed + hand-wash or the washing machine / dishwasher filling etc ) which will be more than suffice for us then in terms of demand, reliability and stability. If you need a hot return circuit to get instant hot water to outlets reasonably far away from the hot water source, then a cylinder would be preferable as you cannot ( sensibly ) achieve a HRC with a combi. If you have or are having solar PV, then a cylinder is a no-brainer to get as much FOC DHW as you can each summer by feeding excess generation into an immersion. What boiler do you currently have, that your plumber has said can be converted to 'sealed and pressurised'? Is it a modern, condensing boiler? There is, essentially, no need to convert the boiler, unless you want to get rid of both the F&E and the CWS ( small and large ) plastic storage tanks in the attic(?) You do 'need' to change the cylinder to an UVC to get the DHW coming out at cold mains potential, which would then remove the CWS tank to boot. If you do ever want to convert the attic, now would be a good time to get rid of both tanks. How much area of UFH will you install, and will it need to run independently? Will you still have rads upstairs? Gas boilers do not like to run UFH directly, as when the floors are warmed up, the heat load is then quite small to keep them there, so the boiler can short cycle. Type that into the search bar here for LOTS of discussion on that

Hi and welcome. This forum is definitely a great place to get help, advice and support by the bucketful. A very worthy project, and we'll all be glad to help wherever we can. I think the best advice I can give at this time would be to consider a turnkey foundation and frame supplier, with guarantees for quality and standards incorporated in the price. This would take you straight to a weathertight shell, and put you in a position where you may feel more comfortable as PM's with a very fast turnaround time. All depends if you're looking at the journey or the destination

I'll PM you the details.

Following my advice / techniques in the thread I linked by creating a bond / up-stand in one would be ample. No need for that product afaic, but if you’re happier ( feel more confident ) to apply that then there’s no reason not to use it. You can ‘paste’ the 3 sides round of the Wedi with clear CT1 immediately prior to dropping the tray in, and then mask up and top coat with more so as to have a wet-on-wet bead of CT1 all the way around. Don’t worry about getting it a bit mucky, as cheap baby wipes will clean it all off perfectly well. Use loads of them, one or two wipes with each before discarding into a carrier bag as you go. Masking the tray before you start the installation would help. I use 2” PVC electrical tape. Stick the tape just shy of where the tiles will stand out from the walls. Peel off the masking the second you finish applying the top seal of CT1 and have done the clean up with wipes.

Do you have a pic of the item please? Would make life easier offering advice if we could see it

Any runs which are long, almost always get jumped up to a double run with my installations. Particularly habitable / quiet rooms where bathrooms which provoke a boost session are away from, eg so they are not made ‘noisy’ by the boost velocity ( whereas with 1x duct they may well have otherwise become ). Needs fully justifying if that means a lot of rooms which then “require” 2x ducts if that means lots of extra hold through steels / beams etc. Well worth the additional effort and cost I’m bedrooms / snugs / studies etc, plus living rooms. MVHR unit = bigger the better….. ……deffo observing the minimum duty is a good point indeed, but with Brink the knee-jerk 4 speed setting can all be user defined to x percentage per increment, so not had any issues oversizing with Brink tbh.

Avoid step 2, just damp it with a few tubs of a wet sponge before laying onto wet adhesive. +1 There isn’t a need for the backer board, and I’m not a big fan of it tbh. Flexible TA is fine for a 10mm runoff, and I’ve always used Ultra unless the client has had BAL included with their bathroom / tile order. To get the CT1 done, just seal up after the tray is laid, if you don’t have any ‘wiggle room’ to “goop up” first.

It’s not the depth of the ducting that’s the issue hiding stuff in tiny spaces, but more the depth necessary to fit the terminal on that takes the ( adjustable flow rate ) air valve, so as per the pics, if you go that route then you will need to take a multi tool to a regular 100mm vent cover and fix it on DIY style, plus you need to attenuate elsewhere for balance and commission. Nick @ CVC Systems works with us a lot to get these kinds of issues dispatched, so I use them for provisional design mostly, plus supply and fit when I’m too busy to do the jobs myself. You don’t ideally, and Nick ( CVC ) is PH certified so we both strive got the same outcome, taking WAY more than just airflow into account That job pictured above would have lived quite happily with a Brink Flair 325, but I paid extra to go with the 400 so the fan was less laboured, the duct connections were next size up, and the pressure required for the same airflow was significantly reduced. All that added together equalled a very happy client who stated that the MVHR was inaudible in bedrooms at night, and barely noticeable when boosting to deal with showers / cooking etc. This is about a lot more than “what size unit”. It’s “why that size of unit” and understanding the pros cons and caveats so you’re making properly informed decisions. One system is avoid is series ducted, I’m not a fan of that at all,, so I always go with radial as of all the systems I’ve specified or installed have performed exceptionally well ( so if it ain’t broken….. )

Designing 2 such projects atm, so have specified the steel penetrations centres to be at 400mm recurring so the posi joists can drop in retrospectively, manipulated to avoid these locations. The joists will be wiggled about to suit during installation, so best to discuss this with the joist designer as well. Remember that posi joists will be in joist hangers in most instances ( not all ) so you will lose 70mm of each 400mm centre void with the wing of the hangers, so that can mean only 2 ducts per joist void. Can be done with most at 400mm c’s and one or two strategic 600mm ‘service sections’ that has beefier joists allowed either side to compensate. I never spec posis at 600mm centres tbh as most designers will fall to the default deflection allowances and beam count to give the best quote, often leaving deflection factored in at north of 12mm of movement allowed. NO THANKS! 👎. I like a structural floor not a reasonably priced trampoline. Also good to remember that rectangular aka oval ducting is available too, so on one current MBC TF I’m bringing fresh for a bedroom and extract for that en-suite up in a ‘4x2’ stud wall with ‘oval’ ( which is rectangular-ish but what the hell ) to allow those two ducts to rise without boxing in in either of the rooms. Also(!) remember that you can get 225x25mm ducting, which can allow you to hide your MVHR ‘duct’ in a 35mm service batten space. Very handy when you have OCD like me lol. I cannot tolerate boxing in, and many of my clients marvel at the solutions I come up with to get away from that requirement.

https://www.toolden.co.uk/sealants-adhesives/expanding-foams/expanding-foams-professional-diy/illbruck-fm330-pro-foam-air-seal-pack-of-12/?gclid=CjwKCAjw3cSSBhBGEiwAVII0Z2aeaxWlZ2NEq0X_5xwDnHpvOKbieG0Bhvxn9-TJV4ewCeAqFFeXIxoCJYYQAvD_BwE Fast delivery. Trusted supplier. I use these a lot.

Do you still need a recommendation? PM me if so and I will give you their details. Not sure he wants to "go public" but I will ask

A1 reverend. 😎. I’d be priming the surfaces but you don’t want the PVA, so use tile adhesive primer or SBR maybe. Foam will adhere to what is behind, if that’s friable then it’ll be shart.

🤣. Short term memory loss lol.

🙄. How many wet window reveals do you have?

Try one with each and watch the results. The grip on the Illbruck is evil by comparison.

For your house, you may need more lol. Remember to soak everything with a 50/50 PVA/water solution 2 mins before foaming with the 330. Cures quicker and harder when you moisten surfaces first. @pocster “No!”